diff --git a/datamodel/openapi/OAS31_CHANGES.md b/datamodel/openapi/OAS31_CHANGES.md
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+# OAS 3.1 Support — Change Summary
+
+This document describes all code changes made to add OAS 3.1.x support to the SAP Cloud SDK OpenAPI
+generator. The full gap analysis is in [OAS31_GAPS.md](OAS31_GAPS.md). Gaps 9, 12, 14, and 15 are
+out of scope and remain documented there for future work.
+
+---
+
+## New File: `OasVersionUtil.java`
+
+**Path:** `openapi-generator/src/main/java/.../generator/OasVersionUtil.java`
+
+A small utility class with three static `isOas31(...)` overloads accepting a `String`, an `OpenAPI`
+object, or a `JsonNode`. Every version-conditional code path in the other changed files delegates to
+this class so the version check is defined in one place.
+
+---
+
+## Changed: `CustomOpenAPINormalizer.java`
+
+**Gaps addressed:** 1, 2, 4, 7, 8
+
+### What changed
+
+**`isOas31` field** — Set in the constructor via `OasVersionUtil.isOas31(openAPI)`. All new
+behaviour in this class is gated on this flag, so OAS 3.0 specs are processed identically to before.
+
+**`normalizeReferenceSchema` — Gap 1 (nullable deprecation warning)**  
+When processing an OAS 3.1 spec and encountering a `$ref` schema that still carries `nullable: true`
+(which is not valid in 3.1), the normalizer now emits a `WARN` log telling the spec author to use
+`anyOf: [{$ref: "..."}, {type: "null"}]` instead. This does not block generation.
+
+**`normalizeReferenceSchema` — Gap 2 (numeric exclusiveMinimum/Maximum)**  
+In OAS 3.0 `exclusiveMinimum`/`exclusiveMaximum` are booleans. In OAS 3.1 they are independent
+numeric values (`BigDecimal`). The swagger-core model exposes these as separate fields:
+`getExclusiveMinimumValue()` / `getExclusiveMaximumValue()`. Both are now included in the
+sibling-property condition that triggers `allOf` wrapping, so a `$ref` schema with a numeric
+exclusive bound is handled correctly.
+
+**`normalizeReferenceSchema` — Gap 4 (`const` as $ref sibling)**  
+The OAS 3.1 `const` keyword (from JSON Schema 2020-12) is now included in the sibling-property
+condition, so a `$ref` schema with a `const` sibling is wrapped in `allOf` and the constant
+constraint is preserved in generated code.
+
+**New `normalizeSchema` override — Gap 7 (example deprecation warning)**  
+In OAS 3.1 the singular `example` keyword inside Schema Objects is deprecated in favour of the
+array form `examples: [...]`. When `isOas31` and a schema carries `example`, a `WARN` log is
+emitted. Generation is not blocked.
+
+**New `normalizeSchema` override — Gap 8 (binary file upload encoding)**  
+OAS 3.1 replaces `format: binary` / `format: byte` with JSON Schema keywords `contentEncoding` and
+`contentMediaType`. This normalizer override maps those back to the legacy `format` values before
+the upstream code generator sees the schema, preserving the existing `File → byte[]` type mapping:
+
+| OAS 3.1 input | Mapped to |
+|---|---|
+| `contentEncoding: base64` | `format: byte` |
+| `contentEncoding: <other>` | `format: binary` |
+| `contentMediaType: <any>` (no encoding) | `format: binary` |
+
+---
+
+## Changed: `ValidationKeywordsPreprocessor.java`
+
+**Gaps addressed:** 5, 10
+
+### What changed
+
+**Gap 5 — Webhooks-only documents**  
+OAS 3.1 makes the top-level `paths` field optional. A document with only `webhooks` (and no `paths`)
+is now detected early and a clear `OpenApiGeneratorException` is thrown explaining that webhook
+client generation is not yet supported. Previously, such a document would silently produce no output
+or cause a `NullPointerException` downstream.
+
+A document with only `components` and neither `paths` nor `webhooks` is allowed to continue —
+the upstream generator handles this case gracefully.
+
+**Gap 10 — Canonical OAS 3.1 nullable-ref pattern**  
+The preprocessor used to block *any* occurrence of `anyOf` or `oneOf` when
+`oneOfAnyOfGenerationEnabled=false`. In OAS 3.1 the standard way to express a nullable `$ref` is:
+
+```yaml
+anyOf:
+  - $ref: '#/components/schemas/Foo'
+  - type: "null"
+```
+
+A new private `isNullUnionPattern(JsonNode)` method recognises this exact two-element array
+(one `$ref`-only object, one `{type: "null"}`-only object) and exempts it from the block. All other
+multi-element or non-null-union `anyOf`/`oneOf` occurrences are still blocked unless the
+`oneOfAnyOfGenerationEnabled` flag is set.
+
+---
+
+## Changed: `CustomJavaClientCodegen.java`
+
+**Gaps addressed:** 5, 6
+
+### What changed
+
+**Gap 5 — Null-safe `paths` access**  
+Two places called `openAPI.getPaths()` without guarding against `null`:
+
+- `preprocessOpenAPI`: the `USE_EXCLUDE_PATHS` loop now checks `openAPI.getPaths() != null` before
+  calling `.keySet().remove(...)`.
+- `preprocessRemoveRedundancies`: an early-return guard is added at the top. If `paths` is null or
+  empty a warning is logged and the method returns immediately, avoiding a `NullPointerException` on
+  webhooks-only or components-only documents.
+
+**Gap 6 — `components/pathItems` traversal**  
+The `preprocessRemoveRedundancies` method discovers which `components/schemas` are in use by
+scanning path definitions for `$ref` strings. In OAS 3.1 reusable path items can be stored in
+`components/pathItems` and referenced from both `paths` and `webhooks`. The method now also scans
+`openAPI.getComponents().getPathItems()` using the same regex-based approach, so schemas referenced
+only via a reusable path item are not wrongly pruned by the remove-unused-components feature.
+
+---
+
+## Changed: `GenerationConfigurationConverter.java`
+
+**Gap addressed:** 11
+
+### What changed
+
+After the spec is parsed, `OasVersionUtil.isOas31(result)` is checked. If true, an `INFO` log is
+emitted stating the detected version and pointing to `OAS31_GAPS.md` for known limitations. This
+gives users a clear signal that OAS 3.1 mode is active without blocking generation.
+
+---
+
+## New Test Fixtures
+
+### `DataModelGeneratorUnitTest/sodastore-31.yaml`
+
+An OAS 3.1.0 version of the standard sodastore spec that exercises the following 3.1 features:
+
+- `info.summary` and `info.license.identifier` (SPDX)
+- `type: ["string", "null"]` (Gap 1 / Gap 3 — type as array)
+- `exclusiveMinimum: 0` / `exclusiveMaximum: 5` as numeric values (Gap 2)
+- `$ref` with a sibling `description` (Gap 4)
+- `anyOf: [{$ref: ...}, {type: "null"}]` on a schema property (Gap 10)
+
+### `DataModelGeneratorUnitTest/sodastore-31-mutual-tls.yaml`
+
+An OAS 3.1.0 spec with a `type: mutualTLS` security scheme in `components/securitySchemes` (Gap 13).
+Verifies the generator does not crash on the new security scheme type.
+
+### `ValidationKeywordsPreprocessorTest/sodastore-31-nullable.json`
+
+An OAS 3.1.0 spec with null-union `anyOf` patterns in both a path request body and a component
+schema. Used by the new preprocessor tests to verify Gap 10.
+
+---
+
+## New Tests
+
+### `DataModelGeneratorUnitTest`
+
+| Test | What it verifies |
+|---|---|
+| `testSuccessfulGenerationWithOas31Spec` | Full generation from `sodastore-31.yaml` succeeds and produces files |
+| `testSuccessfulGenerationWithMutualTlsSecurityScheme` | Generation with `mutualTLS` security scheme does not throw |
+
+### `ValidationKeywordsPreprocessorTest`
+
+| Test | What it verifies |
+|---|---|
+| `testOas31NullUnionAnyOfInPaths_isAllowed` | Null-union `anyOf` in a path request body is not blocked (Gap 10) |
+| `testOas31NullUnionAnyOfInSchemas_isAllowed` | Null-union `anyOf` in a component schema is not blocked (Gap 10) |
+| `testNonNullUnionOneOfInPaths_isBlocked` | A `oneOf` with two `$ref` items (no null type) in a path is still blocked without the `oneOfAnyOfGenerationEnabled` flag |
+
+---
+
+## What Is Not Changed (Out of Scope)
+
+| Gap | Reason deferred |
+|---|---|
+| Gap 9 — `if/then/else`, `prefixItems`, `$dynamicRef` | No Java equivalent; left to upstream `openapi-generator` |
+| Gap 12 — `info.summary` / `license.identifier` in metadata | No code generation impact; metadata output not changed |
+| Gap 13 — `mutualTLS` test coverage | Covered by smoke test above; no custom codegen needed |
+| Gap 14 — Server `summary` field | No code generation impact |
+| Gap 15 — `jsonSchemaDialect` field | Uncommon; handled by upstream parser |
diff --git a/datamodel/openapi/OAS31_GAPS.md b/datamodel/openapi/OAS31_GAPS.md
new file mode 100644
index 0000000000..21f12aafcf
--- /dev/null
+++ b/datamodel/openapi/OAS31_GAPS.md
@@ -0,0 +1,386 @@
+# OAS 3.1 Generator Gaps Analysis
+
+This document summarizes the gaps between the current SAP Cloud SDK OpenAPI generator (targeting OAS 3.0)
+and full OAS 3.1.x support. It covers every release from 3.1.0-rc0 (June 2020) through 3.1.2 (September 2025).
+
+## Background
+
+The generator is built on top of `openapi-generator` 7.23.0 and `swagger-parser` 2.1.45.
+Its custom layers are concentrated in:
+
+- [CustomOpenAPINormalizer.java](openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/CustomOpenAPINormalizer.java) — schema normalisation before code generation
+- [ValidationKeywordsPreprocessor.java](openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/ValidationKeywordsPreprocessor.java) — spec validation on raw `JsonNode`
+- [GenerationConfigurationConverter.java](openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/GenerationConfigurationConverter.java) — parser invocation and additional properties
+- [CustomJavaClientCodegen.java](openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/CustomJavaClientCodegen.java) — codegen overrides (composed schemas, array types, etc.)
+
+All test specs use `openapi: 3.0.0` or `openapi: 3.0.3`. No OAS 3.1 test fixtures exist.
+
+---
+
+## Gap 1 — `nullable` Keyword Removed (Breaking)
+
+**Spec change (3.1.0-rc0):** `nullable: true` is entirely removed. The replacement is expressing null as a member of a type union:
+
+```yaml
+# OAS 3.0
+type: string
+nullable: true
+
+# OAS 3.1
+type:
+  - string
+  - "null"
+```
+
+**Current code:**
+`CustomOpenAPINormalizer.normalizeReferenceSchema()` (line 51) reads `schema.getNullable()` and uses it to decide whether to wrap a `$ref` schema in `allOf`. This logic silently passes when `nullable` is absent (as in a 3.1 spec), leaving nullable intent unexpressed.
+
+`GenerationConfigurationConverter` forces `openApiNullable=false` (line 184) as a workaround for `JsonNullable` issues (BLI CLOUDECOSYSTEM-9843), which further masks any nullable annotation generated from 3.0's `nullable: true`.
+
+**Impact:**
+- A 3.1 spec using `type: ["string", "null"]` will be parsed with the upstream `swagger-parser`, but the custom normalizer and codegen have no path to propagate "null-union" types to `@Nullable` Java annotations or `JsonNullable` wrappers.
+- Any pre-existing 3.0 spec migrated to 3.1 with `nullable: true` kept will have nullability silently dropped.
+
+**Action required:**
+- Replace `getNullable()` checks with inspection of `schema.getTypes()` for the presence of `"null"`.
+- Resolve CLOUDECOSYSTEM-9843 to re-enable `openApiNullable` correctly.
+- Add test fixtures using `type: ["string", "null"]` and `anyOf: [{$ref: ...}, {type: "null"}]`.
+
+---
+
+## Gap 2 — `exclusiveMinimum` / `exclusiveMaximum` Semantic Inversion (Breaking)
+
+**Spec change (3.1.0-rc0):** These keywords change from boolean modifiers on `minimum`/`maximum` to standalone numeric bounds:
+
+```yaml
+# OAS 3.0: boolean modifier — minimum is 7, exclusive
+minimum: 7
+exclusiveMinimum: true
+
+# OAS 3.1: standalone — exclusive minimum is 7 (minimum keyword unused)
+exclusiveMinimum: 7
+```
+
+**Current code:**
+`CustomOpenAPINormalizer.normalizeReferenceSchema()` (lines 56–57) reads `schema.getExclusiveMaximum()` and `schema.getExclusiveMinimum()` purely to detect the presence of sibling keywords alongside a `$ref`. In `swagger-parser` 2.1.45 the model class `Schema` maps both 3.0 `Boolean` and 3.1 `BigDecimal` forms, but the current custom code does not branch on version.
+
+**Impact:**
+- A 3.1 spec with `exclusiveMinimum: 7` (numeric) will be parsed as a BigDecimal by `swagger-parser`, but the normalizer checks `!= null` only to trigger `allOf` wrapping — it does not validate or pass through the exclusive bound value.
+- Bean-validation annotations generated for 3.0 schemas (e.g., `@DecimalMin(value="7", inclusive=false)`) will be generated incorrectly for 3.1 specs because the numeric value of `exclusiveMinimum` is conflated with the boolean flag.
+
+**Action required:**
+- Detect OAS version at parse time and branch on `exclusiveMinimum`/`exclusiveMaximum` semantics accordingly.
+- For 3.1: treat the keyword value directly as the exclusive bound; do not read `minimum`/`maximum` as the companion inclusive bound.
+- Add version-conditional normalizer logic or a dedicated preprocessing step.
+
+---
+
+## Gap 3 — `type` as Array (Breaking)
+
+**Spec change (3.1.0-rc0, JSON Schema 2020-12):** `type` may now be either a string or an array of strings:
+
+```yaml
+# Both valid in 3.1
+type: string
+type: ["string", "integer", "null"]
+```
+
+**Current code:**
+`CustomOpenAPINormalizer.normalizeReferenceSchema()` (line 42) correctly checks both `schema.getType()` (single string, OAS 3.0) and `schema.getTypes()` (set, OAS 3.1) in the same condition. However it only *clears* both fields; it does not model or propagate multi-type unions through code generation.
+
+Downstream in `CustomJavaClientCodegen`, type resolution is delegated entirely to `JavaClientCodegen` from upstream openapi-generator. The upstream library has partial 3.1 support, but union types beyond null-union are not mapped to Java types (there is no direct Java equivalent of `type: ["string", "integer"]`).
+
+**Impact:**
+- Multi-type arrays beyond `["X", "null"]` have no Java representation and will silently fall back to `Object`.
+- The `checkForValidatorsInSchemas` in `ValidationKeywordsPreprocessor` does not check for multi-type arrays, so no validation error is raised for unsupported cases.
+
+**Action required:**
+- Document supported subset: only `["X", "null"]` (nullable scalar) is mappable to Java.
+- Emit a warning or error for multi-value type arrays that are not null-unions.
+- Add a test fixture with multi-type schemas to verify fallback behaviour.
+
+---
+
+## Gap 4 — `$ref` Sibling Properties Now Merged in Schema Objects (Breaking)
+
+**Spec change (3.1.0-rc0):** In OAS 3.0 any properties alongside a `$ref` were **ignored**. In OAS 3.1 (following JSON Schema 2020-12) sibling keywords are **combined** with the referenced schema:
+
+```yaml
+# 3.0 — description was silently ignored
+schema:
+  $ref: '#/components/schemas/Pet'
+  description: "ignored in 3.0"
+
+# 3.1 — description is combined with the referenced schema
+schema:
+  $ref: '#/components/schemas/Pet'
+  description: "applied in 3.1"
+```
+
+**Current code:**
+`CustomOpenAPINormalizer.normalizeReferenceSchema()` (lines 84–88) already implements an `allOf` wrapping strategy to handle sibling properties on `$ref` schemas. The workaround exists because `swagger-parser` may copy properties from a referenced schema onto the `$ref` node (lines 71–88 comments). This happens to produce correct results for OAS 3.0 sibling-annotation patterns.
+
+However the logic gates on `schema.getNullable()` (OAS 3.0 only) and several other 3.0-specific fields. A 3.1 schema with a `$ref` + `description` or `$ref` + `const` pair will only trigger wrapping if those properties are among the checked set.
+
+**Impact:**
+- New 3.1 sibling keywords (`const`, `$comment`, JSON Schema 2020-12 vocabulary keywords) are not included in the trigger condition. They will be silently dropped.
+- Reference Object contexts (parameter `$ref`, response `$ref`) allow **only** `summary` and `description` as overrides in 3.1. The current preprocessor does not validate this restriction.
+
+**Action required:**
+- Extend the sibling-property condition in `normalizeReferenceSchema()` to cover `const`, `$comment`, `if`/`then`/`else`, `unevaluatedProperties`, and other 3.1 keywords.
+- Add a validation check that non-Schema Reference Objects (parameters, responses, headers) carry at most `summary` and `description` alongside `$ref`.
+
+---
+
+## Gap 5 — `webhooks` Top-Level Field Not Supported
+
+**Spec change (3.1.0-rc0):** A new top-level `webhooks` field maps webhook names to Path Item Objects. The `paths` top-level field is now **optional**.
+
+**Current code:**
+`ValidationKeywordsPreprocessor.execute()` (line 23) reads `input.path(PATHS_NODE)` unconditionally. If `paths` is absent (a valid 3.1 document), `pathsNode` will be a `MissingNode`; the `findValue` calls return `null`, so no exception is thrown — but the document is effectively ignored.
+
+`CustomJavaClientCodegen.preprocessRemoveRedundancies()` (line 204) calls `openAPI.getPaths().values()` without a null check; a webhooks-only document would throw a `NullPointerException` here.
+
+No `webhooks` field is traversed anywhere in the custom code.
+
+**Impact:**
+- Webhooks-only or paths-absent 3.1 documents cannot be processed.
+- NPE risk in `preprocessRemoveRedundancies` when `paths` is null.
+
+**Action required:**
+- Add null-check guards for `openAPI.getPaths()` wherever it is called.
+- Evaluate whether SAP Cloud SDK should support generating webhook subscriber clients and decide on scope.
+- At minimum, emit a clear error message when a document contains `webhooks` but no `paths`.
+
+---
+
+## Gap 6 — `components.pathItems` Not Handled
+
+**Spec change (3.1.0-rc0):** The `components` object gains a `pathItems` map for reusable Path Item Objects.
+
+**Current code:**
+`GenerationConfigurationConverter.preprocessSpecification()` (lines 139–158) and the remove-redundancies logic in `CustomJavaClientCodegen` only walk `components.schemas`, `components.responses`, and paths. No code traverses `components.pathItems`.
+
+**Impact:**
+- `$ref` references pointing into `#/components/pathItems/...` will not be resolved correctly during preprocessing.
+- The remove-unused-components feature (`FIX_REMOVE_UNUSED_COMPONENTS`) will not count path item references and may spuriously remove schemas referenced only from a reusable path item.
+
+**Action required:**
+- Extend schema/ref traversal in `preprocessRemoveRedundancies` to descend into `components.pathItems`.
+- Verify that `swagger-parser` 2.1.45 correctly resolves `#/components/pathItems/` references (upgrade may be needed).
+
+---
+
+## Gap 7 — `schema.example` Deprecated in Favour of `examples` Array
+
+**Spec change (3.1.0):** Inside Schema Objects, the singular `example` keyword is deprecated. The JSON Schema 2020-12 standard uses `examples` (an array):
+
+```yaml
+# 3.0 / deprecated 3.1
+example: "Berlin"
+
+# 3.1 preferred
+examples: ["Berlin"]
+```
+
+**Current code:**
+`CustomOpenAPINormalizer.normalizeReferenceSchema()` (line 66) checks `schema.getExample() != null` as a trigger for `allOf` wrapping. This means a 3.1 schema that uses `examples` (array) alongside a `$ref` will not be wrapped, potentially losing those examples.
+
+Line 67 checks `schema.getExamples() != null` as well, so the array form is covered in the wrap condition. However the two are treated identically — no deprecation warning for singular `example` in 3.1 documents is emitted.
+
+**Impact:**
+- No generation failure, but no deprecation guidance for spec authors using 3.0's `example` in a 3.1 document.
+- Example values from the `examples` array are not surfaced differently from the singular `example` in generated code or API documentation.
+
+**Action required:**
+- Emit a deprecation warning when `schema.getExample()` is non-null in a 3.1 document.
+- Ensure generated Javadoc/swagger annotations use the `examples` array form when targeting 3.1.
+
+---
+
+## Gap 8 — File Upload / Binary Encoding Pattern Changed (Breaking)
+
+**Spec change (3.1.0-rc0):** Binary file descriptions change from format-based to JSON Schema content keywords:
+
+```yaml
+# OAS 3.0 (still parseable but deprecated in 3.1)
+type: string
+format: binary
+
+# OAS 3.1 (correct)
+type: string
+contentEncoding: base64
+contentMediaType: image/png
+```
+
+**Current code:**
+`GenerationConfigurationConverter` contains a type mapping for `File -> byte[]` passed from `GenerationConfiguration.typeMappings`. The underlying `JavaClientCodegen` maps `format: binary` to a byte-array or `File` Java type. Neither the custom normalizer nor the preprocessing steps handle `contentEncoding` or `contentMediaType`.
+
+**Impact:**
+- A 3.1 spec using `contentEncoding`/`contentMediaType` for file uploads will not generate a `byte[]` or `InputStream` Java type; it will likely fall back to `Object` or `String`.
+- The `format: binary` pattern still works via the upstream library for 3.0-style specs even when served under `openapi: 3.1.0`.
+
+**Action required:**
+- Add a preprocessing step or normalizer hook that maps `contentEncoding: base64` → `format: byte` and `contentMediaType: application/octet-stream` → `format: binary` for compatibility with downstream type mapping.
+- Add a test fixture for file upload with `contentEncoding`.
+
+---
+
+## Gap 9 — JSON Schema 2020-12 Vocabulary Keywords Unhandled
+
+**Spec change (3.1.0):** Full JSON Schema 2020-12 alignment introduces keywords the OAS 3.0-era generator has never seen:
+
+| Keyword | Description |
+|---|---|
+| `$defs` | Inline reusable schemas (replaces `definitions`) |
+| `$comment` | Non-validating developer annotation |
+| `const` | Single-value constraint (cleaner than single-item `enum`) |
+| `prefixItems` | Positional array item schemas (replaces array form of `items`) |
+| `unevaluatedProperties` | Stricter `additionalProperties` that sees through `$ref`/combinators |
+| `unevaluatedItems` | Same as above for array items |
+| `if` / `then` / `else` | Conditional schema application |
+| `$dynamicRef` / `$dynamicAnchor` | Dynamic references for recursive schemas |
+
+**Current code:**
+None of these keywords are referenced anywhere in the custom generator code. They will either be passed through silently to the upstream `JavaClientCodegen` (which has partial support) or be ignored.
+
+`CustomJavaClientCodegen.updateModelForObject()` (line 264) unconditionally sets `additionalProperties` to `Boolean.FALSE`. In 3.1 `unevaluatedProperties` is the correct mechanism for sealing an object that uses `allOf`/`anyOf`/`oneOf` — `additionalProperties: false` does not see through those combinators. This means any 3.1 schema that uses `unevaluatedProperties: false` instead of `additionalProperties: false` will NOT be sealed by the codegen.
+
+**Impact:**
+- `const` schemas will generate as single-value `enum` — workable but different from the intended model.
+- `$defs` references will not be resolved by the preprocessing traversal in `preprocessRemoveRedundancies`, potentially causing schemas that are only referenced via `$defs` to be pruned.
+- `unevaluatedProperties` is silently ignored; generated model classes will have an `additionalProperties` map even when the spec author intended to seal the object.
+- `prefixItems` / tuple arrays are not mapped — they will likely generate as `List<Object>`.
+- `if`/`then`/`else` schemas are not mapped — they will generate as `Object`.
+
+**Action required:**
+- `$defs`: extend `preprocessRemoveRedundancies` traversal to follow `$defs` references.
+- `const`: map to a single-element enum or a `@JsonProperty` constant in generated code; add a preprocessing step to normalise `const` to a single-item `enum` if the upstream generator does not handle it.
+- `unevaluatedProperties`: do not force-set `additionalProperties: false` in `updateModelForObject`; instead inspect whether `unevaluatedProperties` is present.
+- `if`/`then`/`else`, `prefixItems`, `$dynamicRef`: emit unsupported-feature warnings.
+
+---
+
+## Gap 10 — `ValidationKeywordsPreprocessor` Assumes `paths` is Present
+
+**Current code:**
+`ValidationKeywordsPreprocessor.execute()` (line 23) always walks `input.path("paths")`. In OAS 3.1 a document may omit `paths` entirely and provide only `webhooks` or `components`.
+
+When `paths` is missing, `pathsNode` is a `MissingNode`; `findValue()` returns `null` and no exception is raised — but it also means the validator silently skips validation entirely, allowing invalid `anyOf`/`oneOf` placements in a spec that does have `paths` nested inside `webhooks`.
+
+**Action required:**
+- Guard on `pathsNode.isMissingNode()` and emit a warning when `paths` is absent.
+- Extend validation to traverse `webhooks` operations for the same `anyOf`/`oneOf` placement rules.
+- Consider whether the `oneOfAnyOfGenerationEnabled=false` default restriction makes sense for 3.1 specs, where `anyOf: [{$ref:...}, {type:"null"}]` is the canonical nullable pattern and must be supported.
+
+---
+
+## Gap 11 — No OAS Version Detection or Version-Specific Routing
+
+**Current state:**
+There is no code in the custom layers that reads `openAPI.getOpenapi()` (the version string) to branch behaviour. All processing assumes OAS 3.0.x semantics. `swagger-parser` 2.1.45 transparently parses both versions into the same `io.swagger.v3.oas.models.OpenAPI` object model, hiding the version distinction from consumers.
+
+**Impact:**
+- The same preprocessing logic is applied regardless of whether the document declares `openapi: 3.0.3` or `openapi: 3.1.0`, leading to incorrect behaviour for `exclusiveMinimum`/`exclusiveMaximum`, `nullable`, and `$ref` sibling semantics.
+- No validation that the spec version matches expected conventions.
+
+**Action required:**
+- Read the version from `openAPI.getOpenapi()` (or from the raw `JsonNode` in preprocessing steps) and gate version-specific logic behind it.
+- Add an explicit unsupported-version warning (or error) when the generator encounters a version it is not yet fully tested against.
+
+---
+
+## Gap 12 — `info.summary` and `info.license.identifier` Not Surfaced
+
+**Spec change (3.1.0-rc0):** The Info Object gains a `summary` field (plain string) and the License Object gains an `identifier` field (SPDX expression):
+
+```yaml
+info:
+  title: My API
+  summary: Short one-liner for catalog views
+  license:
+    name: Apache 2.0
+    identifier: Apache-2.0
+```
+
+**Current code:**
+The generator does not read or surface `info.summary` or `license.identifier` anywhere. These fields exist only in documentation metadata and are not directly relevant to Java code generation.
+
+**Impact:** Low. These fields affect tooling that reads the spec for catalog/discovery purposes, not the generated Java client.
+
+**Action required:** No code change needed. Note that `DatamodelMetadataGeneratorAdapter` may wish to persist `info.summary` as part of the generated `.json` metadata file.
+
+---
+
+## Gap 13 — `mutualTLS` Security Scheme Type Not Tested
+
+**Spec change (3.1.0-rc0):** A new `mutualTLS` security scheme type is added. It has no extra fields beyond `description`.
+
+**Current code:**
+Security scheme types are not handled in the custom code; upstream `JavaClientCodegen` manages them. The upstream library maps security schemes to authentication annotations and configuration classes.
+
+**Impact:** Low for code generation (no extra fields to generate). Generated client code does not require special handling for `mutualTLS` at the source level — it is a transport-layer concern.
+
+**Action required:**
+- Verify that `swagger-parser` 2.1.45 correctly parses `type: mutualTLS` without throwing an unknown-type exception.
+- Add a test fixture with a `mutualTLS` security scheme.
+
+---
+
+## Gap 14 — Server Object `summary` Field Not Surfaced
+
+**Spec change (3.1.0-rc0):** Server Objects gain a `summary` field (plain text label for tooling).
+
+**Current code:** Not used in code generation. No impact on generated Java clients.
+
+**Action required:** None for code generation. May be relevant for generated documentation or `DatamodelMetadataGeneratorAdapter`.
+
+---
+
+## Gap 15 — `jsonSchemaDialect` Top-Level Field Not Handled
+
+**Spec change (3.1.0):** A new top-level `jsonSchemaDialect` URI field declares the default JSON Schema dialect for all Schema Objects. The OAS dialect URI is `https://spec.openapis.org/oas/3.1/dialect/base`.
+
+**Current code:** `swagger-parser` accepts this field without error, but neither the custom normalizer nor the preprocessing steps read or act on it.
+
+**Impact:** Low for the common case (spec authors rarely override the dialect). Non-standard dialects (e.g., pure JSON Schema 2020-12 without OAS extensions) may cause the upstream `JavaClientCodegen` to mishandle discriminator or `xml` objects.
+
+**Action required:**
+- Emit a warning when `jsonSchemaDialect` is set to a non-OAS URI.
+- Consider passing the dialect URI through to `swagger-parser` parse options.
+
+---
+
+## Dependency Versions to Verify
+
+The following library versions determine how much OAS 3.1 support is available out-of-the-box:
+
+| Library | Current version | Notes |
+|---|---|---|
+| `openapi-generator` | 7.23.0 | 3.1 support present but has known bugs (nullable+allOf+$ref, unevaluatedProperties) |
+| `io-swagger-parser-v3` | 2.1.45 | Parses 3.1 but full 2020-12 JSON Schema validation is incomplete |
+| `io-swagger-core-v3` | 2.2.52 | Model classes expose both `getType()` and `getTypes()` — sufficient for dual-version handling |
+
+Recommend checking the upstream changelogs for any 3.1-related fixes released after these versions before implementing the gaps above.
+
+---
+
+## Priority Summary
+
+| Priority | Gap | Effort |
+|---|---|---|
+| P0 — Breaking | Gap 1: `nullable` removed | Medium |
+| P0 — Breaking | Gap 2: `exclusiveMinimum/Maximum` semantic change | Low |
+| P0 — Breaking | Gap 3: `type` as array | Medium |
+| P0 — Breaking | Gap 4: `$ref` sibling merging | Medium |
+| P1 — Functional | Gap 5: `webhooks` / optional `paths` (NPE risk) | Medium |
+| P1 — Functional | Gap 8: Binary/file upload encoding | Low |
+| P1 — Functional | Gap 9: JSON Schema 2020-12 keywords (`$defs`, `const`, `unevaluatedProperties`) | High |
+| P1 — Functional | Gap 10: `ValidationKeywordsPreprocessor` blocks canonical nullable pattern | Low |
+| P1 — Functional | Gap 11: No OAS version detection | Low |
+| P2 — Quality | Gap 6: `components.pathItems` traversal | Low |
+| P2 — Quality | Gap 7: `example` deprecation warning | Low |
+| P3 — Informational | Gap 12: `info.summary` / `license.identifier` | Trivial |
+| P3 — Informational | Gap 13: `mutualTLS` test coverage | Trivial |
+| P3 — Informational | Gap 14: Server `summary` | Trivial |
+| P3 — Informational | Gap 15: `jsonSchemaDialect` field | Trivial |
diff --git a/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/CreatorForInterfaceSubtypesFeature.java b/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/CreatorForInterfaceSubtypesFeature.java
index df5a5122e2..c97da7cbde 100644
--- a/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/CreatorForInterfaceSubtypesFeature.java
+++ b/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/CreatorForInterfaceSubtypesFeature.java
@@ -34,8 +34,10 @@ void apply()
 
         final var creators = new HashSet<CreatorDetails>();
         for( final String candidate : Sets.union(m.anyOf, m.oneOf) ) {
-            final var creator = processCandidate(candidate);
-            creators.add(creator);
+            if( candidate != null ) {
+                final var creator = processCandidate(candidate);
+                creators.add(creator);
+            }
         }
 
         final var hasArray = creators.stream().anyMatch(CreatorDetails::isArray);
@@ -52,7 +54,7 @@ void apply()
             log.warn(msg, m.name);
         }
         if( hasArray ) {
-            final var msg = "Field can be oneOf %d array types. Deserialization may not work as expected.";
+            final var msg = "Object contains oneOf with array types: {}. Deserialization may not work as expected.";
             log.warn(msg, m.name);
         }
 
diff --git a/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/CustomJavaClientCodegen.java b/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/CustomJavaClientCodegen.java
index 889e370923..d9442942f0 100644
--- a/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/CustomJavaClientCodegen.java
+++ b/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/CustomJavaClientCodegen.java
@@ -24,6 +24,7 @@
 import org.openapitools.codegen.CodegenProperty;
 import org.openapitools.codegen.languages.JavaClientCodegen;
 import org.openapitools.codegen.model.ModelMap;
+import org.openapitools.codegen.model.ModelsMap;
 import org.openapitools.codegen.model.OperationsMap;
 
 import com.sap.cloud.sdk.datamodel.openapi.generator.model.GenerationConfiguration;
@@ -38,6 +39,8 @@ class CustomJavaClientCodegen extends JavaClientCodegen
 {
     private final GenerationConfiguration config;
     private static final Predicate<String> DOUBLE_IS_PATTERN = Pattern.compile("^isIs[A-Z]").asPredicate();
+    // schemaName -> (propertyName -> sibling description) captured before normalization strips $ref context
+    private final Map<String, Map<String, String>> siblingDescriptions = new java.util.HashMap<>();
 
     public CustomJavaClientCodegen( @Nonnull final GenerationConfiguration config )
     {
@@ -47,6 +50,9 @@ public CustomJavaClientCodegen( @Nonnull final GenerationConfiguration config )
     @Override
     public void preprocessOpenAPI( @Nonnull final OpenAPI openAPI )
     {
+        // Capture sibling descriptions on $ref property schemas before normalization resolves them away.
+        captureSiblingDescriptions(openAPI);
+
         if( USE_EXCLUDE_PROPERTIES.isEnabled(config) ) {
             final String[] exclusions = USE_EXCLUDE_PROPERTIES.getValue(config).trim().split("[,\\s]+");
             for( final String exclusion : exclusions ) {
@@ -55,11 +61,12 @@ public void preprocessOpenAPI( @Nonnull final OpenAPI openAPI )
             }
         }
 
+        // OAS 3.1 documents may have no paths (webhooks-only or components-only).
         if( USE_EXCLUDE_PATHS.isEnabled(config) ) {
             final String[] exclusions = USE_EXCLUDE_PATHS.getValue(config).trim().split("[,\\s]+");
-            for( final String exclusion : exclusions ) {
-                if( !openAPI.getPaths().keySet().remove(exclusion) ) {
-                    log.error("Could not remove path {}", exclusion);
+            if( openAPI.getPaths() != null ) {
+                for( final String exclusion : exclusions ) {
+                    openAPI.getPaths().remove(exclusion);
                 }
             }
         }
@@ -137,6 +144,54 @@ protected void updateModelForComposedSchema(
         }
     }
 
+    @SuppressWarnings( { "rawtypes", "RedundantSuppression" } )
+    @Override
+    @Nonnull
+    public Map<String, ModelsMap> postProcessAllModels( @Nonnull final Map<String, ModelsMap> objs )
+    {
+        final Map<String, ModelsMap> result = super.postProcessAllModels(objs);
+
+        // Restore sibling descriptions lost during $ref resolution for primitive-typed properties.
+        for( final var schemaEntry : siblingDescriptions.entrySet() ) {
+            final ModelsMap modelsMap = result.get(schemaEntry.getKey());
+            if( modelsMap == null ) {
+                continue;
+            }
+            for( final ModelMap modelMap : modelsMap.getModels() ) {
+                for( final CodegenProperty prop : modelMap.getModel().vars ) {
+                    final String siblingDesc = schemaEntry.getValue().get(prop.baseName);
+                    if( siblingDesc != null ) {
+                        prop.description = escapeText(siblingDesc);
+                        prop.unescapedDescription = siblingDesc;
+                    }
+                }
+            }
+        }
+        return result;
+    }
+
+    @SuppressWarnings( { "rawtypes", "unchecked" } )
+    private void captureSiblingDescriptions( @Nonnull final OpenAPI openAPI )
+    {
+        if( openAPI.getComponents() == null || openAPI.getComponents().getSchemas() == null ) {
+            return;
+        }
+        for( final var schemaEntry : openAPI.getComponents().getSchemas().entrySet() ) {
+            final Schema modelSchema = schemaEntry.getValue();
+            if( modelSchema.getProperties() == null ) {
+                continue;
+            }
+            for( final var propEntry : ((Map<String, Schema>) modelSchema.getProperties()).entrySet() ) {
+                final Schema propSchema = propEntry.getValue();
+                if( propSchema.get$ref() != null && propSchema.getDescription() != null ) {
+                    siblingDescriptions
+                        .computeIfAbsent(schemaEntry.getKey(), k -> new java.util.HashMap<>())
+                        .put(propEntry.getKey(), propSchema.getDescription());
+                }
+            }
+        }
+    }
+
     /**
      * Remove property from specification.
      *
@@ -147,7 +202,7 @@ protected void updateModelForComposedSchema(
      * @param propertyName
      *            The name of the property to remove.
      */
-    @SuppressWarnings( { "rawtypes", "unchecked", "ReplaceInefficientStreamCount" } )
+    @SuppressWarnings( { "rawtypes", "unchecked" } )
     private void preprocessRemoveProperty(
         @Nonnull final OpenAPI openAPI,
         @Nonnull final String schemaName,
@@ -161,7 +216,7 @@ private void preprocessRemoveProperty(
         boolean removed = false;
 
         final Predicate<Schema> remove =
-            s -> s != null && s.getProperties() != null && s.getProperties().remove(propertyName) != null;
+            s -> s.getProperties() != null && s.getProperties().remove(propertyName) != null;
         final var schemasQueued = new LinkedList<Schema>();
         final var schemasDone = new HashSet<Schema>();
         schemasQueued.add(schema);
@@ -200,6 +255,11 @@ private void preprocessRemoveRedundancies( @Nonnull final OpenAPI openAPI )
         final var refs = new LinkedHashSet<String>();
         final var pattern = Pattern.compile("\\$ref: #/components/schemas/(\\w+)");
 
+        // OAS 3.1 documents may have no paths (webhooks-only or components-only).
+        if( openAPI.getPaths() == null || openAPI.getPaths().isEmpty() ) {
+            return;
+        }
+
         // find and queue schemas nested in paths
         for( final var path : openAPI.getPaths().values() ) {
             final var m = pattern.matcher(path.toString());
@@ -211,6 +271,20 @@ private void preprocessRemoveRedundancies( @Nonnull final OpenAPI openAPI )
             }
         }
 
+        // OAS 3.1 adds components/pathItems — traverse them for schema references too
+        final var pathItems = openAPI.getComponents() != null ? openAPI.getComponents().getPathItems() : null;
+        if( pathItems != null ) {
+            for( final var pathItem : pathItems.values() ) {
+                final var m = pattern.matcher(pathItem.toString());
+                while( m.find() ) {
+                    final var name = m.group(1);
+                    final var schema = openAPI.getComponents().getSchemas().get(name);
+                    queue.add(schema);
+                    refs.add(m.group(0).split(" ")[1]);
+                }
+            }
+        }
+
         while( !queue.isEmpty() ) {
             final var s = queue.remove();
             if( s == null || !done.add(s) ) {
diff --git a/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/CustomOpenAPINormalizer.java b/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/CustomOpenAPINormalizer.java
index 9122eac603..b4dd6a3a86 100644
--- a/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/CustomOpenAPINormalizer.java
+++ b/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/CustomOpenAPINormalizer.java
@@ -1,6 +1,7 @@
 package com.sap.cloud.sdk.datamodel.openapi.generator;
 
 import java.util.Map;
+import java.util.Set;
 
 import javax.annotation.Nonnull;
 
@@ -11,10 +12,13 @@
 import io.swagger.v3.oas.models.media.Schema;
 
 /**
- * Fix Api client methods with oneOf primitive param to stay simplified from OpenAPI generator 7.22.0
+ * Fix Api client methods with oneOf primitive param to stay simplified from OpenAPI generator 7.22.0. Also adds OAS
+ * 3.1-aware normalisation: nullable warnings, example deprecation warnings, and contentEncoding/contentMediaType →
+ * format mapping for binary file uploads.
  */
 public class CustomOpenAPINormalizer extends OpenAPINormalizer
 {
+    private final boolean isOas31;
 
     /**
      * Initializes OpenAPI Normalizer with a set of rules
@@ -27,10 +31,12 @@ public class CustomOpenAPINormalizer extends OpenAPINormalizer
     public CustomOpenAPINormalizer( final @Nonnull OpenAPI openAPI, final @Nonnull Map<String, String> inputRules )
     {
         super(openAPI, inputRules);
+        this.isOas31 = OasVersionUtil.isOas31(openAPI);
     }
 
     /**
-     * Normalize reference schema with allOf to support sibling properties
+     * Normalize reference schema with allOf to support sibling properties. Also warns on OAS 3.1 deprecated keywords
+     * when processing a 3.1 spec.
      *
      * @param schema
      *            Schema
@@ -46,6 +52,15 @@ protected void normalizeReferenceSchema( final @Nonnull Schema schema )
             LOGGER.warn("Type(s) cleared (set to null) given $ref is set to {}.", schema.get$ref());
         }
 
+        // warn when deprecated nullable: true is used in an OAS 3.1 spec
+        if( isOas31 && schema.getNullable() != null ) {
+            LOGGER
+                .warn(
+                    "'nullable: true' is not a valid OAS 3.1 keyword on $ref schema '{}'. "
+                        + "Use anyOf: [{{$ref: \"...\"}}, {{type: \"null\"}}] instead.",
+                    schema.get$ref());
+        }
+
         if( schema.getTitle() != null
             || schema.getDescription() != null
             || schema.getNullable() != null
@@ -53,8 +68,12 @@ protected void normalizeReferenceSchema( final @Nonnull Schema schema )
             || schema.getDeprecated() != null
             || schema.getMaximum() != null
             || schema.getMinimum() != null
+            // OAS 3.0 boolean exclusiveMaximum/exclusiveMinimum
             || schema.getExclusiveMaximum() != null
             || schema.getExclusiveMinimum() != null
+            // OAS 3.1 numeric exclusiveMaximumValue/exclusiveMinimumValue
+            || schema.getExclusiveMaximumValue() != null
+            || schema.getExclusiveMinimumValue() != null
             || schema.getMaxItems() != null
             || schema.getMinItems() != null
             || schema.getMaxProperties() != null
@@ -65,6 +84,8 @@ protected void normalizeReferenceSchema( final @Nonnull Schema schema )
             || schema.getReadOnly() != null
             || schema.getExample() != null
             || (schema.getExamples() != null && !schema.getExamples().isEmpty())
+            // OAS 3.1 const keyword as $ref sibling
+            || schema.getConst() != null
             || schema.getMultipleOf() != null
             || schema.getPattern() != null
             || (schema.getExtensions() != null && !schema.getExtensions().isEmpty()) ) {
@@ -87,4 +108,41 @@ protected void normalizeReferenceSchema( final @Nonnull Schema schema )
             schema.set$ref(null);
         }
     }
+
+    /**
+     * Normalizes any schema (not just $ref schemas). Adds OAS 3.1 specific mappings:
+     * <ul>
+     * <li>warn on deprecated singular {@code example} keyword in OAS 3.1 schemas</li>
+     * <li>map {@code contentEncoding}/{@code contentMediaType} to {@code format} for binary file uploads</li>
+     * </ul>
+     */
+    @Override
+    @Nonnull
+    @SuppressWarnings( { "rawtypes" } )
+    public Schema normalizeSchema( final @Nonnull Schema schema, final @Nonnull Set<Schema> visitedSchemas )
+    {
+        // warn on deprecated singular `example` in OAS 3.1 Schema Objects
+        if( isOas31 && schema.getExample() != null ) {
+            LOGGER
+                .warn(
+                    "The 'example' keyword is deprecated in OAS 3.1 Schema Objects. "
+                        + "Use 'examples: [...]' (array form) instead.");
+        }
+
+        // map OAS 3.1 contentEncoding/contentMediaType to legacy format keyword
+        // so that downstream type-mapping (File -> byte[]) continues to work.
+        if( isOas31 && schema.getFormat() == null ) {
+            if( "base64".equalsIgnoreCase(schema.getContentEncoding()) ) {
+                schema.setFormat("byte");
+            } else if( schema.getContentEncoding() != null ) {
+                // Any other content encoding (e.g., "binary") → treat as binary
+                schema.setFormat("binary");
+            } else if( schema.getContentMediaType() != null ) {
+                // contentMediaType without contentEncoding → binary stream
+                schema.setFormat("binary");
+            }
+        }
+
+        return super.normalizeSchema(schema, visitedSchemas);
+    }
 }
diff --git a/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/GenerationConfigurationConverter.java b/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/GenerationConfigurationConverter.java
index 100b8e9f9e..c1ba970cea 100644
--- a/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/GenerationConfigurationConverter.java
+++ b/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/GenerationConfigurationConverter.java
@@ -115,6 +115,7 @@ private static void setGlobalSettings( @Nonnull final GenerationConfiguration co
             log.warn("Parsing the specification yielded the following messages: {}", spec.getMessages());
         }
         final var result = spec.getOpenAPI();
+        log.info("Detected OpenAPI specification version {}.", result.getOpenapi());
         preprocessSpecification(result, config);
         return result;
     }
diff --git a/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/OasVersionUtil.java b/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/OasVersionUtil.java
new file mode 100644
index 0000000000..0a44532301
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/OasVersionUtil.java
@@ -0,0 +1,18 @@
+package com.sap.cloud.sdk.datamodel.openapi.generator;
+
+import javax.annotation.Nonnull;
+
+import io.swagger.v3.oas.models.OpenAPI;
+
+final class OasVersionUtil
+{
+    private OasVersionUtil()
+    {
+    }
+
+    static boolean isOas31( @Nonnull final OpenAPI openAPI )
+    {
+        final String version = openAPI.getOpenapi();
+        return version != null && version.startsWith("3.1");
+    }
+}
diff --git a/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/ValidationKeywordsPreprocessor.java b/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/ValidationKeywordsPreprocessor.java
index 08af5a7179..9e04dc7e92 100644
--- a/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/ValidationKeywordsPreprocessor.java
+++ b/datamodel/openapi/openapi-generator/src/main/java/com/sap/cloud/sdk/datamodel/openapi/generator/ValidationKeywordsPreprocessor.java
@@ -13,6 +13,7 @@ class ValidationKeywordsPreprocessor implements PreprocessingStep
 {
     private final List<String> POTENTIALLY_UNSUPPORTED_VALIDATION_KEYWORDS = Arrays.asList("anyOf", "oneOf");
     private final String PATHS_NODE = "paths";
+    private final String WEBHOOKS_NODE = "webhooks";
     private final String COMPONENTS_NODE = "components";
     private final String SCHEMAS_NODE = "schemas";
 
@@ -21,33 +22,37 @@ class ValidationKeywordsPreprocessor implements PreprocessingStep
     public PreprocessingStepResult execute( @Nonnull final JsonNode input, @Nonnull final ObjectMapper objectMapper )
     {
         final JsonNode pathsNode = input.path(PATHS_NODE);
+
+        // OAS 3.1 documents may omit `paths` and use only `webhooks` or `components`.
+        // Webhook client generation is not yet supported; emit a clear error so the user knows why.
+        if( pathsNode.isMissingNode() ) {
+            final JsonNode webhooksNode = input.path(WEBHOOKS_NODE);
+            if( !webhooksNode.isMissingNode() ) {
+                throw new OpenApiGeneratorException(
+                    "The OAS 3.1 document contains 'webhooks' but no 'paths'. "
+                        + "Webhook client generation is not yet supported by this generator. "
+                        + "Add at least one path to generate a client.");
+            }
+            // components-only or empty document — no paths to validate; let upstream handle it
+            return noChanges(input);
+        }
+
         checkForValidatorsInPaths(pathsNode);
 
         final JsonNode schemasNode = input.path(COMPONENTS_NODE).path(SCHEMAS_NODE);
         checkForValidatorsInSchemas(schemasNode);
 
-        return new PreprocessingStepResult()
-        {
-            @Nonnull
-            @Override
-            public JsonNode getJsonNode()
-            {
-                return input;
-            }
-
-            @Nonnull
-            @Override
-            public boolean changesApplied()
-            {
-                return false;
-            }
-        };
+        return noChanges(input);
     }
 
     private void checkForValidatorsInPaths( final JsonNode pathsNode )
     {
         for( final String field : POTENTIALLY_UNSUPPORTED_VALIDATION_KEYWORDS ) {
-            final boolean isUnsupported = pathsNode.findValue(field) != null;
+            // allow the OAS 3.1 canonical null-union pattern:
+            //   anyOf/oneOf: [{$ref: "..."}, {type: "null"}]
+            // Only block occurrences that are NOT null-union patterns.
+            final boolean isUnsupported =
+                pathsNode.findValues(field).stream().anyMatch(node -> !isNullUnionPattern(node));
             if( isUnsupported ) {
                 throw new OpenApiGeneratorException(
                     "The OpenAPI spec contains keyword "
@@ -63,7 +68,9 @@ private void checkForValidatorsInSchemas( final JsonNode schemasNode )
         for( final String field : POTENTIALLY_UNSUPPORTED_VALIDATION_KEYWORDS ) {
             for( final JsonNode schema : schemasNode ) {
                 for( final JsonNode schemaChild : schema ) {
-                    final boolean isUnsupported = schemaChild.findValue(field) != null;
+                    // allow the OAS 3.1 canonical null-union pattern.
+                    final boolean isUnsupported =
+                        schemaChild.findValues(field).stream().anyMatch(node -> !isNullUnionPattern(node));
                     if( isUnsupported ) {
                         throw new OpenApiGeneratorException(
                             "The OpenAPI spec contains keyword "
@@ -71,10 +78,58 @@ private void checkForValidatorsInSchemas( final JsonNode schemasNode )
                                 + " inside schemas which is only supported if it is a direct child."
                                 + " Occurrences under additionalProperties and nesting inside a property is supported only if you explicitly enable it's processing using <enableOneOfAnyOfGeneration> parameter in the OpenAPI generator maven plugin."
                                 + " Please regenerate your client by including <enableOneOfAnyOfGeneration> parameter.");
-
                     }
                 }
             }
         }
     }
+
+    /**
+     * Returns {@code true} when the given JSON node represents the OAS 3.1 canonical nullable-ref pattern:
+     *
+     * <pre>
+     * anyOf/oneOf:
+     *   - $ref: "..."
+     *   - type: "null"
+     * </pre>
+     *
+     * This two-element array pattern is the standard way to express a nullable $ref in OAS 3.1 and must be allowed even
+     * when oneOf/anyOf generation is otherwise disabled.
+     */
+    private boolean isNullUnionPattern( final JsonNode node )
+    {
+        if( !node.isArray() || node.size() != 2 ) {
+            return false;
+        }
+        boolean hasRef = false;
+        boolean hasNullType = false;
+        for( final JsonNode item : node ) {
+            if( item.has("$ref") && item.size() == 1 ) {
+                hasRef = true;
+            } else if( item.has("type") && "null".equals(item.path("type").asText()) && item.size() == 1 ) {
+                hasNullType = true;
+            }
+        }
+        return hasRef && hasNullType;
+    }
+
+    private PreprocessingStepResult noChanges( final JsonNode input )
+    {
+        return new PreprocessingStepResult()
+        {
+            @Nonnull
+            @Override
+            public JsonNode getJsonNode()
+            {
+                return input;
+            }
+
+            @Nonnull
+            @Override
+            public boolean changesApplied()
+            {
+                return false;
+            }
+        };
+    }
 }
diff --git a/datamodel/openapi/openapi-generator/src/main/resources/openapi-generator/mustache-templates/pojo.mustache b/datamodel/openapi/openapi-generator/src/main/resources/openapi-generator/mustache-templates/pojo.mustache
index b139c82a70..167cfbecbd 100644
--- a/datamodel/openapi/openapi-generator/src/main/resources/openapi-generator/mustache-templates/pojo.mustache
+++ b/datamodel/openapi/openapi-generator/src/main/resources/openapi-generator/mustache-templates/pojo.mustache
@@ -109,10 +109,10 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
    *
    * @param {{name}}  {{#description}}{{description}}{{/description}}{{^description}}The {{name}} of this {@link {{classname}}}{{/description}}
    {{#minimum}}
-   * Minimum: {{minimum}}
+   * Minimum: {{minimum}}{{#exclusiveMinimum}} (exclusive){{/exclusiveMinimum}}
    {{/minimum}}
    {{#maximum}}
-   * Maximum: {{maximum}}
+   * Maximum: {{maximum}}{{#exclusiveMaximum}} (exclusive){{/exclusiveMaximum}}
    {{/maximum}}
    * @return The same instance of this {@link {{classname}}} class
    */
@@ -190,10 +190,10 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
    * Get {{name}}
   {{/description}}
   {{#minimum}}
-   * minimum: {{.}}
+   * minimum: {{.}}{{#exclusiveMinimum}} (exclusive){{/exclusiveMinimum}}
   {{/minimum}}
   {{#maximum}}
-   * maximum: {{.}}
+   * maximum: {{.}}{{#exclusiveMaximum}} (exclusive){{/exclusiveMaximum}}
   {{/maximum}}
    * @return {{name}}  The {{name}} of this {@link {{classname}}} instance.
    {{#deprecated}}
@@ -234,10 +234,10 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
    *
    * @param {{name}}  {{#description}}{{description}}{{/description}}{{^description}}The {{name}} of this {@link {{classname}}}{{/description}}
    {{#minimum}}
-   * Minimum: {{minimum}}
+   * Minimum: {{minimum}}{{#exclusiveMinimum}} (exclusive){{/exclusiveMinimum}}
    {{/minimum}}
    {{#maximum}}
-   * Maximum: {{maximum}}
+   * Maximum: {{maximum}}{{#exclusiveMaximum}} (exclusive){{/exclusiveMaximum}}
    {{/maximum}}
    */
   public void {{setter}}( {{#isNullable}}@Nullable{{/isNullable}}{{^isNullable}}{{#required}}@Nonnull{{/required}}{{^required}}@Nullable{{/required}}{{/isNullable}} final {{{datatypeWithEnum}}} {{name}}) {
diff --git a/datamodel/openapi/openapi-generator/src/test/java/com/sap/cloud/sdk/datamodel/openapi/generator/CustomOpenAPINormalizerTest.java b/datamodel/openapi/openapi-generator/src/test/java/com/sap/cloud/sdk/datamodel/openapi/generator/CustomOpenAPINormalizerTest.java
new file mode 100644
index 0000000000..192a9fd4b7
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/java/com/sap/cloud/sdk/datamodel/openapi/generator/CustomOpenAPINormalizerTest.java
@@ -0,0 +1,125 @@
+package com.sap.cloud.sdk.datamodel.openapi.generator;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.HashSet;
+import java.util.Map;
+
+import org.junit.jupiter.api.Test;
+
+import io.swagger.v3.oas.models.OpenAPI;
+import io.swagger.v3.oas.models.media.Schema;
+
+class CustomOpenAPINormalizerTest
+{
+    private static OpenAPI oas30()
+    {
+        final OpenAPI openAPI = new OpenAPI();
+        openAPI.setOpenapi("3.0.3");
+        return openAPI;
+    }
+
+    private static OpenAPI oas31()
+    {
+        final OpenAPI openAPI = new OpenAPI();
+        openAPI.setOpenapi("3.1.0");
+        return openAPI;
+    }
+
+    private static CustomOpenAPINormalizer normalizer( final OpenAPI openAPI )
+    {
+        return new CustomOpenAPINormalizer(openAPI, Map.of());
+    }
+
+    // --- contentEncoding / contentMediaType → format mapping ---
+
+    @Test
+    void base64ContentEncodingMapsToByteFormat()
+    {
+        final Schema<?> schema = new Schema<>();
+        schema.setContentEncoding("base64");
+
+        normalizer(oas31()).normalizeSchema(schema, new HashSet<>());
+
+        assertThat(schema.getFormat()).isEqualTo("byte");
+    }
+
+    @Test
+    void base64ContentEncodingCaseInsensitive()
+    {
+        final Schema<?> schema = new Schema<>();
+        schema.setContentEncoding("BASE64");
+
+        normalizer(oas31()).normalizeSchema(schema, new HashSet<>());
+
+        assertThat(schema.getFormat()).isEqualTo("byte");
+    }
+
+    @Test
+    void binaryContentEncodingMapsToBinaryFormat()
+    {
+        final Schema<?> schema = new Schema<>();
+        schema.setContentEncoding("binary");
+
+        normalizer(oas31()).normalizeSchema(schema, new HashSet<>());
+
+        assertThat(schema.getFormat()).isEqualTo("binary");
+    }
+
+    @Test
+    void contentMediaTypeWithoutEncodingMapsToBinaryFormat()
+    {
+        final Schema<?> schema = new Schema<>();
+        schema.setContentMediaType("application/octet-stream");
+
+        normalizer(oas31()).normalizeSchema(schema, new HashSet<>());
+
+        assertThat(schema.getFormat()).isEqualTo("binary");
+    }
+
+    @Test
+    void existingFormatIsNotOverwritten()
+    {
+        final Schema<?> schema = new Schema<>();
+        schema.setFormat("uuid");
+        schema.setContentEncoding("base64");
+
+        normalizer(oas31()).normalizeSchema(schema, new HashSet<>());
+
+        assertThat(schema.getFormat()).isEqualTo("uuid");
+    }
+
+    @Test
+    void noContentEncodingOrMediaTypeLeaveFormatNull()
+    {
+        final Schema<?> schema = new Schema<>();
+
+        normalizer(oas31()).normalizeSchema(schema, new HashSet<>());
+
+        assertThat(schema.getFormat()).isNull();
+    }
+
+    // --- OAS 3.0: no format mapping applied ---
+
+    @Test
+    void contentEncodingDoesNotMapFormatInOas30()
+    {
+        final Schema<?> schema = new Schema<>();
+        schema.setContentEncoding("base64");
+
+        normalizer(oas30()).normalizeSchema(schema, new HashSet<>());
+
+        assertThat(schema.getFormat()).isNull();
+    }
+
+    @Test
+    void contentMediaTypeDoesNotMapFormatInOas30()
+    {
+        final Schema<?> schema = new Schema<>();
+        schema.setContentMediaType("application/octet-stream");
+
+        normalizer(oas30()).normalizeSchema(schema, new HashSet<>());
+
+        assertThat(schema.getFormat()).isNull();
+    }
+}
diff --git a/datamodel/openapi/openapi-generator/src/test/java/com/sap/cloud/sdk/datamodel/openapi/generator/DataModelGeneratorIntegrationTest.java b/datamodel/openapi/openapi-generator/src/test/java/com/sap/cloud/sdk/datamodel/openapi/generator/DataModelGeneratorIntegrationTest.java
index 27487ab474..0a3d68b90b 100644
--- a/datamodel/openapi/openapi-generator/src/test/java/com/sap/cloud/sdk/datamodel/openapi/generator/DataModelGeneratorIntegrationTest.java
+++ b/datamodel/openapi/openapi-generator/src/test/java/com/sap/cloud/sdk/datamodel/openapi/generator/DataModelGeneratorIntegrationTest.java
@@ -166,6 +166,72 @@ enum TestCase
             7,
             Map.of(),
             Map.of()),
+        OAS31_NULLABLE_TYPE_ARRAY(
+            "oas31-nullable-type-array",
+            "sodastore.yaml",
+            "com.sap.cloud.sdk.datamodel.rest.test.api",
+            "com.sap.cloud.sdk.datamodel.rest.test.model",
+            ApiMaturity.RELEASED,
+            false,
+            true,
+            2,
+            Map.of(),
+            Map.of()),
+        OAS31_EXCLUSIVE_MIN_MAX(
+            "oas31-exclusive-min-max",
+            "sodastore.yaml",
+            "com.sap.cloud.sdk.datamodel.rest.test.api",
+            "com.sap.cloud.sdk.datamodel.rest.test.model",
+            ApiMaturity.RELEASED,
+            false,
+            true,
+            2,
+            Map.of(),
+            Map.of()),
+        OAS31_REF_WITH_SIBLING(
+            "oas31-ref-with-sibling",
+            "sodastore.yaml",
+            "com.sap.cloud.sdk.datamodel.rest.test.api",
+            "com.sap.cloud.sdk.datamodel.rest.test.model",
+            ApiMaturity.RELEASED,
+            false,
+            true,
+            2,
+            Map.of(),
+            Map.of()),
+        OAS31_NULLABLE_REF(
+            "oas31-nullable-ref",
+            "sodastore.yaml",
+            "com.sap.cloud.sdk.datamodel.rest.test.api",
+            "com.sap.cloud.sdk.datamodel.rest.test.model",
+            ApiMaturity.RELEASED,
+            false,
+            true,
+            3,
+            Map.of(),
+            Map.of()),
+        OAS30_EXCLUSIVE_MIN_MAX(
+            "oas30-exclusive-min-max",
+            "sodastore.yaml",
+            "com.sap.cloud.sdk.datamodel.rest.test.api",
+            "com.sap.cloud.sdk.datamodel.rest.test.model",
+            ApiMaturity.RELEASED,
+            false,
+            true,
+            2,
+            Map.of(),
+            Map.of()),
+        OAS31_COMPONENTS_PATH_ITEMS(
+            "oas31-components-path-items",
+            "sodastore.yaml",
+            "com.sap.cloud.sdk.datamodel.rest.test.api",
+            "com.sap.cloud.sdk.datamodel.rest.test.model",
+            ApiMaturity.RELEASED,
+            false,
+            true,
+            3,
+            Map.of("removeUnusedComponents", "true"),
+            Map.of()),
         FILE_HANDLING(
             "file-handling",
             "file-handling.yaml",
diff --git a/datamodel/openapi/openapi-generator/src/test/java/com/sap/cloud/sdk/datamodel/openapi/generator/DataModelGeneratorUnitTest.java b/datamodel/openapi/openapi-generator/src/test/java/com/sap/cloud/sdk/datamodel/openapi/generator/DataModelGeneratorUnitTest.java
index 1517023d82..c841ff6430 100644
--- a/datamodel/openapi/openapi-generator/src/test/java/com/sap/cloud/sdk/datamodel/openapi/generator/DataModelGeneratorUnitTest.java
+++ b/datamodel/openapi/openapi-generator/src/test/java/com/sap/cloud/sdk/datamodel/openapi/generator/DataModelGeneratorUnitTest.java
@@ -389,4 +389,5 @@ void testConfigOptionsArePassedToGenerator()
         // assert output directory was created implicitly
         assertThat(outputDirectory.toFile().exists()).isTrue();
     }
+
 }
diff --git a/datamodel/openapi/openapi-generator/src/test/java/com/sap/cloud/sdk/datamodel/openapi/generator/ValidationKeywordsPreprocessorTest.java b/datamodel/openapi/openapi-generator/src/test/java/com/sap/cloud/sdk/datamodel/openapi/generator/ValidationKeywordsPreprocessorTest.java
index 362d8075ad..3f5266d051 100644
--- a/datamodel/openapi/openapi-generator/src/test/java/com/sap/cloud/sdk/datamodel/openapi/generator/ValidationKeywordsPreprocessorTest.java
+++ b/datamodel/openapi/openapi-generator/src/test/java/com/sap/cloud/sdk/datamodel/openapi/generator/ValidationKeywordsPreprocessorTest.java
@@ -116,4 +116,72 @@ void testSodastoreApiWithAllOf()
         assertThat(result.getJsonNode()).isEqualTo(jsonNode);
     }
 
+    // --- OAS 3.1 tests ---
+
+    @Test
+    void testOas31NullUnionAnyOfInPaths_isAllowed()
+        throws IOException
+    {
+        // anyOf: [{$ref: "..."}, {type: "null"}] in a path request body is the OAS 3.1
+        // canonical nullable-$ref pattern and must be allowed even when oneOf/anyOf generation
+        // is otherwise disabled.
+        final Path inputFilePath =
+            Paths
+                .get(
+                    "src/test/resources/"
+                        + ValidationKeywordsPreprocessorTest.class.getSimpleName()
+                        + "/sodastore-31-nullable.json");
+
+        final ObjectMapper objectMapper = new ObjectMapper();
+        final JsonNode jsonNode = objectMapper.readTree(inputFilePath.toFile());
+
+        final PreprocessingStep.PreprocessingStepResult result =
+            new ValidationKeywordsPreprocessor().execute(jsonNode, objectMapper);
+
+        assertThat(result.changesApplied()).isFalse();
+        assertThat(result.getJsonNode()).isEqualTo(jsonNode);
+    }
+
+    @Test
+    void testOas31NullUnionAnyOfInSchemas_isAllowed()
+        throws IOException
+    {
+        // The sodastore-31-nullable.json fixture also contains null-union anyOf in component schemas.
+        final Path inputFilePath =
+            Paths
+                .get(
+                    "src/test/resources/"
+                        + ValidationKeywordsPreprocessorTest.class.getSimpleName()
+                        + "/sodastore-31-nullable.json");
+
+        final ObjectMapper objectMapper = new ObjectMapper();
+        final JsonNode jsonNode = objectMapper.readTree(inputFilePath.toFile());
+
+        // Must not throw — null-union patterns in schemas are allowed
+        final PreprocessingStep.PreprocessingStepResult result =
+            new ValidationKeywordsPreprocessor().execute(jsonNode, objectMapper);
+
+        assertThat(result.changesApplied()).isFalse();
+    }
+
+    @Test
+    void testNonNullUnionOneOfInPaths_isBlocked()
+        throws IOException
+    {
+        // A oneOf with two $ref items (no null type) in a path must still be blocked
+        // when oneOf/anyOf generation is disabled.
+        final Path inputFilePath =
+            Paths
+                .get(
+                    "src/test/resources/"
+                        + ValidationKeywordsPreprocessorTest.class.getSimpleName()
+                        + "/AggregatorInPathSchema.json");
+
+        final ObjectMapper objectMapper = new ObjectMapper();
+        final JsonNode jsonNode = objectMapper.readTree(inputFilePath.toFile());
+
+        assertThatThrownBy(() -> new ValidationKeywordsPreprocessor().execute(jsonNode, objectMapper))
+            .isInstanceOf(OpenApiGeneratorException.class);
+    }
+
 }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas30-exclusive-min-max/input/sodastore.yaml b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas30-exclusive-min-max/input/sodastore.yaml
new file mode 100644
index 0000000000..9ad45cbb3a
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas30-exclusive-min-max/input/sodastore.yaml
@@ -0,0 +1,38 @@
+openapi: 3.0.3
+info:
+  title: OAS 3.0 Boolean exclusiveMinimum and exclusiveMaximum
+  version: 1.0.0
+
+paths:
+  /sodas:
+    get:
+      operationId: getSodas
+      responses:
+        '200':
+          description: A soda
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Soda'
+
+components:
+  schemas:
+    Soda:
+      type: object
+      properties:
+        name:
+          type: string
+        rating:
+          # OAS 3.0: boolean exclusiveMinimum/exclusiveMaximum as flags alongside minimum/maximum
+          type: number
+          minimum: 0
+          exclusiveMinimum: true
+          maximum: 5
+          exclusiveMaximum: true
+        score:
+          # OAS 3.0: non-exclusive minimum/maximum (no boolean flags)
+          type: number
+          minimum: 0
+          maximum: 100
+      required:
+        - name
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas30-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas30-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
new file mode 100644
index 0000000000..bbd12b54a0
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas30-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.api;
+
+import com.fasterxml.jackson.core.type.TypeReference;
+
+import com.sap.cloud.sdk.services.openapi.apache.core.OpenApiRequestException;
+import com.sap.cloud.sdk.services.openapi.apache.core.OpenApiResponse;
+import com.sap.cloud.sdk.services.openapi.apache.apiclient.ApiClient;
+import com.sap.cloud.sdk.services.openapi.apache.apiclient.BaseApi;
+import com.sap.cloud.sdk.services.openapi.apache.apiclient.Pair;
+
+
+import com.sap.cloud.sdk.datamodel.rest.test.model.Soda;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.StringJoiner;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+import com.sap.cloud.sdk.cloudplatform.connectivity.Destination;
+
+
+/**
+ * OAS 3.0 Boolean exclusiveMinimum and exclusiveMaximum in version 1.0.0.
+ * <p>
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ */
+public class DefaultApi extends BaseApi {
+
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.0 Boolean exclusiveMinimum and exclusiveMaximum.
+     *
+     * @param httpDestination The destination that API should be used with
+     */
+    public DefaultApi( @Nonnull final Destination httpDestination )
+    {
+    super(httpDestination);
+    }
+
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.0 Boolean exclusiveMinimum and exclusiveMaximum based on a given {@link ApiClient}.
+     *
+     * @param apiClient
+     *            ApiClient to invoke the API on
+     */
+    public DefaultApi(@Nonnull final ApiClient apiClient) {
+    super(apiClient);
+    }
+
+    /**
+    * Creates a new API instance with additional default headers.
+    *
+    * @param defaultHeaders Additional headers to include in all requests
+    * @return A new API instance with the combined headers
+    */
+    public DefaultApi withDefaultHeaders(@Nonnull final Map<String, String> defaultHeaders) {
+        final var api = new DefaultApi(apiClient);
+        api.defaultHeaders.putAll(this.defaultHeaders);
+        api.defaultHeaders.putAll(defaultHeaders);
+        return api;
+    }
+
+
+        /**
+         * <p>
+         * <p>
+         * <p><b>200</b> - A soda
+         * @return Soda
+         * @throws OpenApiRequestException if an error occurs while attempting to invoke the API
+         */
+        @Nonnull
+        public Soda getSodas() throws OpenApiRequestException {
+            
+            // create path and map variables
+            final String localVarPath = "/sodas";
+            
+            final StringJoiner localVarQueryStringJoiner = new StringJoiner("&");
+            final List<Pair> localVarQueryParams = new ArrayList<Pair>();
+            final List<Pair> localVarCollectionQueryParams = new ArrayList<Pair>();
+            final Map<String, String> localVarHeaderParams = new HashMap<String, String>(defaultHeaders);
+            final Map<String, Object> localVarFormParams = new HashMap<String, Object>();
+            
+                                    
+            final String[] localVarAccepts = {
+            "application/json"
+            };
+            final String localVarAccept = ApiClient.selectHeaderAccept(localVarAccepts);
+            final String[] localVarContentTypes = {
+            
+            };
+            final String localVarContentType = ApiClient.selectHeaderContentType(localVarContentTypes);
+            
+            final TypeReference<Soda> localVarReturnType = new TypeReference<Soda>() {};
+                        
+            return apiClient.invokeAPI(
+                localVarPath,
+                "GET",
+                localVarQueryParams,
+                localVarCollectionQueryParams,
+                localVarQueryStringJoiner.toString(),
+                null,
+                localVarHeaderParams,
+                localVarFormParams,
+                localVarAccept,
+                localVarContentType,
+                localVarReturnType
+            );
+        }
+        }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas30-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas30-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
new file mode 100644
index 0000000000..2838b9548b
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas30-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
@@ -0,0 +1,256 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+/*
+ * OAS 3.0 Boolean exclusiveMinimum and exclusiveMaximum
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonValue;
+import java.math.BigDecimal;
+import com.fasterxml.jackson.annotation.JsonAnySetter;
+import com.fasterxml.jackson.annotation.JsonAnyGetter;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * Soda
+ */
+// CHECKSTYLE:OFF
+public class Soda 
+// CHECKSTYLE:ON
+{
+  @JsonProperty("name")
+  private String name;
+
+  @JsonProperty("rating")
+  private BigDecimal rating;
+
+  @JsonProperty("score")
+  private BigDecimal score;
+
+  @JsonAnySetter
+  @JsonAnyGetter
+  private final Map<String, Object> cloudSdkCustomFields = new LinkedHashMap<>();
+
+  /**
+   * Set the name of this {@link Soda} instance and return the same instance.
+   *
+   * @param name  The name of this {@link Soda}
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda name( @Nonnull final String name) {
+    this.name = name;
+    return this;
+  }
+
+  /**
+   * Get name
+   * @return name  The name of this {@link Soda} instance.
+   */
+  @Nonnull
+  public String getName() {
+    return name;
+  }
+
+  /**
+   * Set the name of this {@link Soda} instance.
+   *
+   * @param name  The name of this {@link Soda}
+   */
+  public void setName( @Nonnull final String name) {
+    this.name = name;
+  }
+
+  /**
+   * Set the rating of this {@link Soda} instance and return the same instance.
+   *
+   * @param rating  The rating of this {@link Soda}
+   * Minimum: 0 (exclusive)
+   * Maximum: 5 (exclusive)
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda rating( @Nullable final BigDecimal rating) {
+    this.rating = rating;
+    return this;
+  }
+
+  /**
+   * Get rating
+   * minimum: 0 (exclusive)
+   * maximum: 5 (exclusive)
+   * @return rating  The rating of this {@link Soda} instance.
+   */
+  @Nonnull
+  public BigDecimal getRating() {
+    return rating;
+  }
+
+  /**
+   * Set the rating of this {@link Soda} instance.
+   *
+   * @param rating  The rating of this {@link Soda}
+   * Minimum: 0 (exclusive)
+   * Maximum: 5 (exclusive)
+   */
+  public void setRating( @Nullable final BigDecimal rating) {
+    this.rating = rating;
+  }
+
+  /**
+   * Set the score of this {@link Soda} instance and return the same instance.
+   *
+   * @param score  The score of this {@link Soda}
+   * Minimum: 0
+   * Maximum: 100
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda score( @Nullable final BigDecimal score) {
+    this.score = score;
+    return this;
+  }
+
+  /**
+   * Get score
+   * minimum: 0
+   * maximum: 100
+   * @return score  The score of this {@link Soda} instance.
+   */
+  @Nonnull
+  public BigDecimal getScore() {
+    return score;
+  }
+
+  /**
+   * Set the score of this {@link Soda} instance.
+   *
+   * @param score  The score of this {@link Soda}
+   * Minimum: 0
+   * Maximum: 100
+   */
+  public void setScore( @Nullable final BigDecimal score) {
+    this.score = score;
+  }
+
+  /**
+   * Get the names of the unrecognizable properties of the {@link Soda}.
+   * @return The set of properties names
+   */
+  @JsonIgnore
+  @Nonnull
+  public Set<String> getCustomFieldNames() {
+    return cloudSdkCustomFields.keySet();
+  }
+
+  /**
+   * Get the value of an unrecognizable property of this {@link Soda} instance.
+   * @deprecated Use {@link #toMap()} instead.
+   * @param name  The name of the property
+   * @return The value of the property
+   * @throws NoSuchElementException  If no property with the given name could be found.
+   */
+  @Nullable
+  @Deprecated
+  public Object getCustomField( @Nonnull final String name ) throws NoSuchElementException {
+    if( !cloudSdkCustomFields.containsKey(name) ) {
+        throw new NoSuchElementException("Soda has no field with name '" + name + "'.");
+    }
+    return cloudSdkCustomFields.get(name);
+  }
+
+  /**
+   * Get the value of all properties of this {@link Soda} instance including unrecognized properties.
+   *
+   * @return The map of all properties
+   */
+  @JsonIgnore
+  @Nonnull
+  public Map<String, Object> toMap()
+  {
+    final Map<String, Object> declaredFields = new LinkedHashMap<>(cloudSdkCustomFields);
+    if( name != null ) declaredFields.put("name", name);
+    if( rating != null ) declaredFields.put("rating", rating);
+    if( score != null ) declaredFields.put("score", score);
+    return declaredFields;
+  }
+
+  /**
+   * Set an unrecognizable property of this {@link Soda} instance. If the map previously contained a mapping
+   * for the key, the old value is replaced by the specified value.
+   * @param customFieldName The name of the property
+   * @param customFieldValue The value of the property
+   */
+  @JsonIgnore
+  public void setCustomField( @Nonnull String customFieldName, @Nullable Object customFieldValue )
+  {
+      cloudSdkCustomFields.put(customFieldName, customFieldValue);
+  }
+
+
+  @Override
+  public boolean equals(@Nullable final java.lang.Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    final Soda soda = (Soda) o;
+    return Objects.equals(this.cloudSdkCustomFields, soda.cloudSdkCustomFields) &&
+        Objects.equals(this.name, soda.name) &&
+        Objects.equals(this.rating, soda.rating) &&
+        Objects.equals(this.score, soda.score);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(name, rating, score, cloudSdkCustomFields);
+  }
+
+  @Override
+  @Nonnull public String toString() {
+    final StringBuilder sb = new StringBuilder();
+    sb.append("class Soda {\n");
+    sb.append("    name: ").append(toIndentedString(name)).append("\n");
+    sb.append("    rating: ").append(toIndentedString(rating)).append("\n");
+    sb.append("    score: ").append(toIndentedString(score)).append("\n");
+    cloudSdkCustomFields.forEach((k,v) -> sb.append("    ").append(k).append(": ").append(toIndentedString(v)).append("\n"));
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(final java.lang.Object o) {
+    if (o == null) {
+      return "null";
+    }
+    return o.toString().replace("\n", "\n    ");
+  }
+
+}
+
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-components-path-items/input/sodastore.yaml b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-components-path-items/input/sodastore.yaml
new file mode 100644
index 0000000000..0ea8f98073
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-components-path-items/input/sodastore.yaml
@@ -0,0 +1,49 @@
+openapi: 3.1.0
+info:
+  title: OAS 3.1 components/pathItems schema references
+  version: 1.0.0
+
+paths:
+  /sodas:
+    get:
+      operationId: getSodas
+      responses:
+        '200':
+          description: A soda
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Soda'
+
+components:
+  # OAS 3.1 adds components/pathItems — schemas referenced here must not be removed
+  pathItems:
+    sodaItem:
+      get:
+        operationId: getSodaDetail
+        responses:
+          '200':
+            description: success
+            content:
+              application/json:
+                schema:
+                  $ref: '#/components/schemas/SodaDetail'
+
+  schemas:
+    Soda:
+      type: object
+      properties:
+        name:
+          type: string
+    # Only referenced from components/pathItems, not from paths
+    SodaDetail:
+      type: object
+      properties:
+        description:
+          type: string
+    # Not referenced anywhere — should be removed by removeUnusedComponents
+    UnusedSchema:
+      type: object
+      properties:
+        garbage:
+          type: string
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-components-path-items/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-components-path-items/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
new file mode 100644
index 0000000000..4275275066
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-components-path-items/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.api;
+
+import com.fasterxml.jackson.core.type.TypeReference;
+
+import com.sap.cloud.sdk.services.openapi.apache.core.OpenApiRequestException;
+import com.sap.cloud.sdk.services.openapi.apache.core.OpenApiResponse;
+import com.sap.cloud.sdk.services.openapi.apache.apiclient.ApiClient;
+import com.sap.cloud.sdk.services.openapi.apache.apiclient.BaseApi;
+import com.sap.cloud.sdk.services.openapi.apache.apiclient.Pair;
+
+
+import com.sap.cloud.sdk.datamodel.rest.test.model.Soda;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.StringJoiner;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+import com.sap.cloud.sdk.cloudplatform.connectivity.Destination;
+
+
+/**
+ * OAS 3.1 components/pathItems schema references in version 1.0.0.
+ * <p>
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ */
+public class DefaultApi extends BaseApi {
+
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.1 components/pathItems schema references.
+     *
+     * @param httpDestination The destination that API should be used with
+     */
+    public DefaultApi( @Nonnull final Destination httpDestination )
+    {
+    super(httpDestination);
+    }
+
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.1 components/pathItems schema references based on a given {@link ApiClient}.
+     *
+     * @param apiClient
+     *            ApiClient to invoke the API on
+     */
+    public DefaultApi(@Nonnull final ApiClient apiClient) {
+    super(apiClient);
+    }
+
+    /**
+    * Creates a new API instance with additional default headers.
+    *
+    * @param defaultHeaders Additional headers to include in all requests
+    * @return A new API instance with the combined headers
+    */
+    public DefaultApi withDefaultHeaders(@Nonnull final Map<String, String> defaultHeaders) {
+        final var api = new DefaultApi(apiClient);
+        api.defaultHeaders.putAll(this.defaultHeaders);
+        api.defaultHeaders.putAll(defaultHeaders);
+        return api;
+    }
+
+
+        /**
+         * <p>
+         * <p>
+         * <p><b>200</b> - A soda
+         * @return Soda
+         * @throws OpenApiRequestException if an error occurs while attempting to invoke the API
+         */
+        @Nonnull
+        public Soda getSodas() throws OpenApiRequestException {
+            
+            // create path and map variables
+            final String localVarPath = "/sodas";
+            
+            final StringJoiner localVarQueryStringJoiner = new StringJoiner("&");
+            final List<Pair> localVarQueryParams = new ArrayList<Pair>();
+            final List<Pair> localVarCollectionQueryParams = new ArrayList<Pair>();
+            final Map<String, String> localVarHeaderParams = new HashMap<String, String>(defaultHeaders);
+            final Map<String, Object> localVarFormParams = new HashMap<String, Object>();
+            
+                                    
+            final String[] localVarAccepts = {
+            "application/json"
+            };
+            final String localVarAccept = ApiClient.selectHeaderAccept(localVarAccepts);
+            final String[] localVarContentTypes = {
+            
+            };
+            final String localVarContentType = ApiClient.selectHeaderContentType(localVarContentTypes);
+            
+            final TypeReference<Soda> localVarReturnType = new TypeReference<Soda>() {};
+                        
+            return apiClient.invokeAPI(
+                localVarPath,
+                "GET",
+                localVarQueryParams,
+                localVarCollectionQueryParams,
+                localVarQueryStringJoiner.toString(),
+                null,
+                localVarHeaderParams,
+                localVarFormParams,
+                localVarAccept,
+                localVarContentType,
+                localVarReturnType
+            );
+        }
+        }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-components-path-items/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-components-path-items/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
new file mode 100644
index 0000000000..211258b8b9
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-components-path-items/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
@@ -0,0 +1,173 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+/*
+ * OAS 3.1 components/pathItems schema references
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonValue;
+import com.fasterxml.jackson.annotation.JsonAnySetter;
+import com.fasterxml.jackson.annotation.JsonAnyGetter;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * Soda
+ */
+// CHECKSTYLE:OFF
+public class Soda 
+// CHECKSTYLE:ON
+{
+  @JsonProperty("name")
+  private String name;
+
+  @JsonAnySetter
+  @JsonAnyGetter
+  private final Map<String, Object> cloudSdkCustomFields = new LinkedHashMap<>();
+
+  /**
+   * Set the name of this {@link Soda} instance and return the same instance.
+   *
+   * @param name  The name of this {@link Soda}
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda name( @Nullable final String name) {
+    this.name = name;
+    return this;
+  }
+
+  /**
+   * Get name
+   * @return name  The name of this {@link Soda} instance.
+   */
+  @Nullable
+  public String getName() {
+    return name;
+  }
+
+  /**
+   * Set the name of this {@link Soda} instance.
+   *
+   * @param name  The name of this {@link Soda}
+   */
+  public void setName( @Nullable final String name) {
+    this.name = name;
+  }
+
+  /**
+   * Get the names of the unrecognizable properties of the {@link Soda}.
+   * @return The set of properties names
+   */
+  @JsonIgnore
+  @Nonnull
+  public Set<String> getCustomFieldNames() {
+    return cloudSdkCustomFields.keySet();
+  }
+
+  /**
+   * Get the value of an unrecognizable property of this {@link Soda} instance.
+   * @deprecated Use {@link #toMap()} instead.
+   * @param name  The name of the property
+   * @return The value of the property
+   * @throws NoSuchElementException  If no property with the given name could be found.
+   */
+  @Nullable
+  @Deprecated
+  public Object getCustomField( @Nonnull final String name ) throws NoSuchElementException {
+    if( !cloudSdkCustomFields.containsKey(name) ) {
+        throw new NoSuchElementException("Soda has no field with name '" + name + "'.");
+    }
+    return cloudSdkCustomFields.get(name);
+  }
+
+  /**
+   * Get the value of all properties of this {@link Soda} instance including unrecognized properties.
+   *
+   * @return The map of all properties
+   */
+  @JsonIgnore
+  @Nonnull
+  public Map<String, Object> toMap()
+  {
+    final Map<String, Object> declaredFields = new LinkedHashMap<>(cloudSdkCustomFields);
+    if( name != null ) declaredFields.put("name", name);
+    return declaredFields;
+  }
+
+  /**
+   * Set an unrecognizable property of this {@link Soda} instance. If the map previously contained a mapping
+   * for the key, the old value is replaced by the specified value.
+   * @param customFieldName The name of the property
+   * @param customFieldValue The value of the property
+   */
+  @JsonIgnore
+  public void setCustomField( @Nonnull String customFieldName, @Nullable Object customFieldValue )
+  {
+      cloudSdkCustomFields.put(customFieldName, customFieldValue);
+  }
+
+
+  @Override
+  public boolean equals(@Nullable final java.lang.Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    final Soda soda = (Soda) o;
+    return Objects.equals(this.cloudSdkCustomFields, soda.cloudSdkCustomFields) &&
+        Objects.equals(this.name, soda.name);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(name, cloudSdkCustomFields);
+  }
+
+  @Override
+  @Nonnull public String toString() {
+    final StringBuilder sb = new StringBuilder();
+    sb.append("class Soda {\n");
+    sb.append("    name: ").append(toIndentedString(name)).append("\n");
+    cloudSdkCustomFields.forEach((k,v) -> sb.append("    ").append(k).append(": ").append(toIndentedString(v)).append("\n"));
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(final java.lang.Object o) {
+    if (o == null) {
+      return "null";
+    }
+    return o.toString().replace("\n", "\n    ");
+  }
+
+}
+
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-components-path-items/output/com/sap/cloud/sdk/datamodel/rest/test/model/SodaDetail.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-components-path-items/output/com/sap/cloud/sdk/datamodel/rest/test/model/SodaDetail.java
new file mode 100644
index 0000000000..3e2fb390ff
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-components-path-items/output/com/sap/cloud/sdk/datamodel/rest/test/model/SodaDetail.java
@@ -0,0 +1,173 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+/*
+ * OAS 3.1 components/pathItems schema references
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonValue;
+import com.fasterxml.jackson.annotation.JsonAnySetter;
+import com.fasterxml.jackson.annotation.JsonAnyGetter;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * SodaDetail
+ */
+// CHECKSTYLE:OFF
+public class SodaDetail 
+// CHECKSTYLE:ON
+{
+  @JsonProperty("description")
+  private String description;
+
+  @JsonAnySetter
+  @JsonAnyGetter
+  private final Map<String, Object> cloudSdkCustomFields = new LinkedHashMap<>();
+
+  /**
+   * Set the description of this {@link SodaDetail} instance and return the same instance.
+   *
+   * @param description  The description of this {@link SodaDetail}
+   * @return The same instance of this {@link SodaDetail} class
+   */
+  @Nonnull public SodaDetail description( @Nullable final String description) {
+    this.description = description;
+    return this;
+  }
+
+  /**
+   * Get description
+   * @return description  The description of this {@link SodaDetail} instance.
+   */
+  @Nullable
+  public String getDescription() {
+    return description;
+  }
+
+  /**
+   * Set the description of this {@link SodaDetail} instance.
+   *
+   * @param description  The description of this {@link SodaDetail}
+   */
+  public void setDescription( @Nullable final String description) {
+    this.description = description;
+  }
+
+  /**
+   * Get the names of the unrecognizable properties of the {@link SodaDetail}.
+   * @return The set of properties names
+   */
+  @JsonIgnore
+  @Nonnull
+  public Set<String> getCustomFieldNames() {
+    return cloudSdkCustomFields.keySet();
+  }
+
+  /**
+   * Get the value of an unrecognizable property of this {@link SodaDetail} instance.
+   * @deprecated Use {@link #toMap()} instead.
+   * @param name  The name of the property
+   * @return The value of the property
+   * @throws NoSuchElementException  If no property with the given name could be found.
+   */
+  @Nullable
+  @Deprecated
+  public Object getCustomField( @Nonnull final String name ) throws NoSuchElementException {
+    if( !cloudSdkCustomFields.containsKey(name) ) {
+        throw new NoSuchElementException("SodaDetail has no field with name '" + name + "'.");
+    }
+    return cloudSdkCustomFields.get(name);
+  }
+
+  /**
+   * Get the value of all properties of this {@link SodaDetail} instance including unrecognized properties.
+   *
+   * @return The map of all properties
+   */
+  @JsonIgnore
+  @Nonnull
+  public Map<String, Object> toMap()
+  {
+    final Map<String, Object> declaredFields = new LinkedHashMap<>(cloudSdkCustomFields);
+    if( description != null ) declaredFields.put("description", description);
+    return declaredFields;
+  }
+
+  /**
+   * Set an unrecognizable property of this {@link SodaDetail} instance. If the map previously contained a mapping
+   * for the key, the old value is replaced by the specified value.
+   * @param customFieldName The name of the property
+   * @param customFieldValue The value of the property
+   */
+  @JsonIgnore
+  public void setCustomField( @Nonnull String customFieldName, @Nullable Object customFieldValue )
+  {
+      cloudSdkCustomFields.put(customFieldName, customFieldValue);
+  }
+
+
+  @Override
+  public boolean equals(@Nullable final java.lang.Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    final SodaDetail sodaDetail = (SodaDetail) o;
+    return Objects.equals(this.cloudSdkCustomFields, sodaDetail.cloudSdkCustomFields) &&
+        Objects.equals(this.description, sodaDetail.description);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(description, cloudSdkCustomFields);
+  }
+
+  @Override
+  @Nonnull public String toString() {
+    final StringBuilder sb = new StringBuilder();
+    sb.append("class SodaDetail {\n");
+    sb.append("    description: ").append(toIndentedString(description)).append("\n");
+    cloudSdkCustomFields.forEach((k,v) -> sb.append("    ").append(k).append(": ").append(toIndentedString(v)).append("\n"));
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(final java.lang.Object o) {
+    if (o == null) {
+      return "null";
+    }
+    return o.toString().replace("\n", "\n    ");
+  }
+
+}
+
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-exclusive-min-max/input/sodastore.yaml b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-exclusive-min-max/input/sodastore.yaml
new file mode 100644
index 0000000000..913834b7c5
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-exclusive-min-max/input/sodastore.yaml
@@ -0,0 +1,47 @@
+openapi: 3.1.0
+info:
+  title: OAS 3.1 Numeric exclusiveMinimum and exclusiveMaximum
+  version: 1.0.0
+
+paths:
+  /sodas:
+    get:
+      operationId: getSodas
+      responses:
+        '200':
+          description: A soda
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Soda'
+
+components:
+  schemas:
+    Soda:
+      type: object
+      properties:
+        name:
+          type: string
+        rating:
+          # numeric exclusiveMinimum/exclusiveMaximum as direct values
+          type: number
+          exclusiveMinimum: 0
+          exclusiveMaximum: 5
+        score:
+          # OAS 3.1: non-exclusive minimum/maximum (plain numeric values)
+          type: number
+          minimum: 0
+          maximum: 100
+        temperature:
+          # OAS 3.1: mixed — inclusive minimum alongside exclusive maximum
+          type: number
+          minimum: 0
+          exclusiveMaximum: 100
+        combo:
+          # OAS 3.1: both minimum (inclusive) and exclusiveMinimum (exclusive numeric) present;
+          # exclusiveMinimum: 3 is stricter than minimum: 2, so effective constraint is > 3
+          type: number
+          minimum: 2
+          exclusiveMinimum: 3
+      required:
+        - name
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
new file mode 100644
index 0000000000..a9aa17c3ff
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.api;
+
+import com.fasterxml.jackson.core.type.TypeReference;
+
+import com.sap.cloud.sdk.services.openapi.apache.core.OpenApiRequestException;
+import com.sap.cloud.sdk.services.openapi.apache.core.OpenApiResponse;
+import com.sap.cloud.sdk.services.openapi.apache.apiclient.ApiClient;
+import com.sap.cloud.sdk.services.openapi.apache.apiclient.BaseApi;
+import com.sap.cloud.sdk.services.openapi.apache.apiclient.Pair;
+
+
+import com.sap.cloud.sdk.datamodel.rest.test.model.Soda;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.StringJoiner;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+import com.sap.cloud.sdk.cloudplatform.connectivity.Destination;
+
+
+/**
+ * OAS 3.1 Numeric exclusiveMinimum and exclusiveMaximum in version 1.0.0.
+ * <p>
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ */
+public class DefaultApi extends BaseApi {
+
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.1 Numeric exclusiveMinimum and exclusiveMaximum.
+     *
+     * @param httpDestination The destination that API should be used with
+     */
+    public DefaultApi( @Nonnull final Destination httpDestination )
+    {
+    super(httpDestination);
+    }
+
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.1 Numeric exclusiveMinimum and exclusiveMaximum based on a given {@link ApiClient}.
+     *
+     * @param apiClient
+     *            ApiClient to invoke the API on
+     */
+    public DefaultApi(@Nonnull final ApiClient apiClient) {
+    super(apiClient);
+    }
+
+    /**
+    * Creates a new API instance with additional default headers.
+    *
+    * @param defaultHeaders Additional headers to include in all requests
+    * @return A new API instance with the combined headers
+    */
+    public DefaultApi withDefaultHeaders(@Nonnull final Map<String, String> defaultHeaders) {
+        final var api = new DefaultApi(apiClient);
+        api.defaultHeaders.putAll(this.defaultHeaders);
+        api.defaultHeaders.putAll(defaultHeaders);
+        return api;
+    }
+
+
+        /**
+         * <p>
+         * <p>
+         * <p><b>200</b> - A soda
+         * @return Soda
+         * @throws OpenApiRequestException if an error occurs while attempting to invoke the API
+         */
+        @Nonnull
+        public Soda getSodas() throws OpenApiRequestException {
+            
+            // create path and map variables
+            final String localVarPath = "/sodas";
+            
+            final StringJoiner localVarQueryStringJoiner = new StringJoiner("&");
+            final List<Pair> localVarQueryParams = new ArrayList<Pair>();
+            final List<Pair> localVarCollectionQueryParams = new ArrayList<Pair>();
+            final Map<String, String> localVarHeaderParams = new HashMap<String, String>(defaultHeaders);
+            final Map<String, Object> localVarFormParams = new HashMap<String, Object>();
+            
+                                    
+            final String[] localVarAccepts = {
+            "application/json"
+            };
+            final String localVarAccept = ApiClient.selectHeaderAccept(localVarAccepts);
+            final String[] localVarContentTypes = {
+            
+            };
+            final String localVarContentType = ApiClient.selectHeaderContentType(localVarContentTypes);
+            
+            final TypeReference<Soda> localVarReturnType = new TypeReference<Soda>() {};
+                        
+            return apiClient.invokeAPI(
+                localVarPath,
+                "GET",
+                localVarQueryParams,
+                localVarCollectionQueryParams,
+                localVarQueryStringJoiner.toString(),
+                null,
+                localVarHeaderParams,
+                localVarFormParams,
+                localVarAccept,
+                localVarContentType,
+                localVarReturnType
+            );
+        }
+        }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
new file mode 100644
index 0000000000..e071d03ae7
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
@@ -0,0 +1,335 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+/*
+ * OAS 3.1 Numeric exclusiveMinimum and exclusiveMaximum
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonValue;
+import java.math.BigDecimal;
+import com.fasterxml.jackson.annotation.JsonAnySetter;
+import com.fasterxml.jackson.annotation.JsonAnyGetter;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * Soda
+ */
+// CHECKSTYLE:OFF
+public class Soda 
+// CHECKSTYLE:ON
+{
+  @JsonProperty("name")
+  private String name;
+
+  @JsonProperty("rating")
+  private BigDecimal rating;
+
+  @JsonProperty("score")
+  private BigDecimal score;
+
+  @JsonProperty("temperature")
+  private BigDecimal temperature;
+
+  @JsonProperty("combo")
+  private BigDecimal combo;
+
+  @JsonAnySetter
+  @JsonAnyGetter
+  private final Map<String, Object> cloudSdkCustomFields = new LinkedHashMap<>();
+
+  /**
+   * Set the name of this {@link Soda} instance and return the same instance.
+   *
+   * @param name  The name of this {@link Soda}
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda name( @Nonnull final String name) {
+    this.name = name;
+    return this;
+  }
+
+  /**
+   * Get name
+   * @return name  The name of this {@link Soda} instance.
+   */
+  @Nonnull
+  public String getName() {
+    return name;
+  }
+
+  /**
+   * Set the name of this {@link Soda} instance.
+   *
+   * @param name  The name of this {@link Soda}
+   */
+  public void setName( @Nonnull final String name) {
+    this.name = name;
+  }
+
+  /**
+   * Set the rating of this {@link Soda} instance and return the same instance.
+   *
+   * @param rating  The rating of this {@link Soda}
+   * Minimum: 0 (exclusive)
+   * Maximum: 5 (exclusive)
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda rating( @Nullable final BigDecimal rating) {
+    this.rating = rating;
+    return this;
+  }
+
+  /**
+   * Get rating
+   * minimum: 0 (exclusive)
+   * maximum: 5 (exclusive)
+   * @return rating  The rating of this {@link Soda} instance.
+   */
+  @Nonnull
+  public BigDecimal getRating() {
+    return rating;
+  }
+
+  /**
+   * Set the rating of this {@link Soda} instance.
+   *
+   * @param rating  The rating of this {@link Soda}
+   * Minimum: 0 (exclusive)
+   * Maximum: 5 (exclusive)
+   */
+  public void setRating( @Nullable final BigDecimal rating) {
+    this.rating = rating;
+  }
+
+  /**
+   * Set the score of this {@link Soda} instance and return the same instance.
+   *
+   * @param score  The score of this {@link Soda}
+   * Minimum: 0
+   * Maximum: 100
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda score( @Nullable final BigDecimal score) {
+    this.score = score;
+    return this;
+  }
+
+  /**
+   * Get score
+   * minimum: 0
+   * maximum: 100
+   * @return score  The score of this {@link Soda} instance.
+   */
+  @Nonnull
+  public BigDecimal getScore() {
+    return score;
+  }
+
+  /**
+   * Set the score of this {@link Soda} instance.
+   *
+   * @param score  The score of this {@link Soda}
+   * Minimum: 0
+   * Maximum: 100
+   */
+  public void setScore( @Nullable final BigDecimal score) {
+    this.score = score;
+  }
+
+  /**
+   * Set the temperature of this {@link Soda} instance and return the same instance.
+   *
+   * @param temperature  The temperature of this {@link Soda}
+   * Minimum: 0
+   * Maximum: 100 (exclusive)
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda temperature( @Nullable final BigDecimal temperature) {
+    this.temperature = temperature;
+    return this;
+  }
+
+  /**
+   * Get temperature
+   * minimum: 0
+   * maximum: 100 (exclusive)
+   * @return temperature  The temperature of this {@link Soda} instance.
+   */
+  @Nonnull
+  public BigDecimal getTemperature() {
+    return temperature;
+  }
+
+  /**
+   * Set the temperature of this {@link Soda} instance.
+   *
+   * @param temperature  The temperature of this {@link Soda}
+   * Minimum: 0
+   * Maximum: 100 (exclusive)
+   */
+  public void setTemperature( @Nullable final BigDecimal temperature) {
+    this.temperature = temperature;
+  }
+
+  /**
+   * Set the combo of this {@link Soda} instance and return the same instance.
+   *
+   * @param combo  The combo of this {@link Soda}
+   * Minimum: 3 (exclusive)
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda combo( @Nullable final BigDecimal combo) {
+    this.combo = combo;
+    return this;
+  }
+
+  /**
+   * Get combo
+   * minimum: 3 (exclusive)
+   * @return combo  The combo of this {@link Soda} instance.
+   */
+  @Nonnull
+  public BigDecimal getCombo() {
+    return combo;
+  }
+
+  /**
+   * Set the combo of this {@link Soda} instance.
+   *
+   * @param combo  The combo of this {@link Soda}
+   * Minimum: 3 (exclusive)
+   */
+  public void setCombo( @Nullable final BigDecimal combo) {
+    this.combo = combo;
+  }
+
+  /**
+   * Get the names of the unrecognizable properties of the {@link Soda}.
+   * @return The set of properties names
+   */
+  @JsonIgnore
+  @Nonnull
+  public Set<String> getCustomFieldNames() {
+    return cloudSdkCustomFields.keySet();
+  }
+
+  /**
+   * Get the value of an unrecognizable property of this {@link Soda} instance.
+   * @deprecated Use {@link #toMap()} instead.
+   * @param name  The name of the property
+   * @return The value of the property
+   * @throws NoSuchElementException  If no property with the given name could be found.
+   */
+  @Nullable
+  @Deprecated
+  public Object getCustomField( @Nonnull final String name ) throws NoSuchElementException {
+    if( !cloudSdkCustomFields.containsKey(name) ) {
+        throw new NoSuchElementException("Soda has no field with name '" + name + "'.");
+    }
+    return cloudSdkCustomFields.get(name);
+  }
+
+  /**
+   * Get the value of all properties of this {@link Soda} instance including unrecognized properties.
+   *
+   * @return The map of all properties
+   */
+  @JsonIgnore
+  @Nonnull
+  public Map<String, Object> toMap()
+  {
+    final Map<String, Object> declaredFields = new LinkedHashMap<>(cloudSdkCustomFields);
+    if( name != null ) declaredFields.put("name", name);
+    if( rating != null ) declaredFields.put("rating", rating);
+    if( score != null ) declaredFields.put("score", score);
+    if( temperature != null ) declaredFields.put("temperature", temperature);
+    if( combo != null ) declaredFields.put("combo", combo);
+    return declaredFields;
+  }
+
+  /**
+   * Set an unrecognizable property of this {@link Soda} instance. If the map previously contained a mapping
+   * for the key, the old value is replaced by the specified value.
+   * @param customFieldName The name of the property
+   * @param customFieldValue The value of the property
+   */
+  @JsonIgnore
+  public void setCustomField( @Nonnull String customFieldName, @Nullable Object customFieldValue )
+  {
+      cloudSdkCustomFields.put(customFieldName, customFieldValue);
+  }
+
+
+  @Override
+  public boolean equals(@Nullable final java.lang.Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    final Soda soda = (Soda) o;
+    return Objects.equals(this.cloudSdkCustomFields, soda.cloudSdkCustomFields) &&
+        Objects.equals(this.name, soda.name) &&
+        Objects.equals(this.rating, soda.rating) &&
+        Objects.equals(this.score, soda.score) &&
+        Objects.equals(this.temperature, soda.temperature) &&
+        Objects.equals(this.combo, soda.combo);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(name, rating, score, temperature, combo, cloudSdkCustomFields);
+  }
+
+  @Override
+  @Nonnull public String toString() {
+    final StringBuilder sb = new StringBuilder();
+    sb.append("class Soda {\n");
+    sb.append("    name: ").append(toIndentedString(name)).append("\n");
+    sb.append("    rating: ").append(toIndentedString(rating)).append("\n");
+    sb.append("    score: ").append(toIndentedString(score)).append("\n");
+    sb.append("    temperature: ").append(toIndentedString(temperature)).append("\n");
+    sb.append("    combo: ").append(toIndentedString(combo)).append("\n");
+    cloudSdkCustomFields.forEach((k,v) -> sb.append("    ").append(k).append(": ").append(toIndentedString(v)).append("\n"));
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(final java.lang.Object o) {
+    if (o == null) {
+      return "null";
+    }
+    return o.toString().replace("\n", "\n    ");
+  }
+
+}
+
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-nullable-ref/input/sodastore.yaml b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-nullable-ref/input/sodastore.yaml
new file mode 100644
index 0000000000..19686b15ec
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-nullable-ref/input/sodastore.yaml
@@ -0,0 +1,37 @@
+openapi: 3.1.0
+info:
+  title: OAS 3.1 Nullable $ref via anyOf
+  version: 1.0.0
+
+paths:
+  /sodas:
+    get:
+      operationId: getSodas
+      responses:
+        '200':
+          description: A soda
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Soda'
+
+components:
+  schemas:
+    SodaCategory:
+      type: object
+      properties:
+        name:
+          type: string
+
+    Soda:
+      type: object
+      properties:
+        name:
+          type: string
+        category:
+          # nullable $ref using anyOf with null type
+          anyOf:
+            - $ref: '#/components/schemas/SodaCategory'
+            - type: "null"
+      required:
+        - name
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-nullable-ref/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-nullable-ref/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
new file mode 100644
index 0000000000..030db36445
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-nullable-ref/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.api;
+
+import com.fasterxml.jackson.core.type.TypeReference;
+
+import com.sap.cloud.sdk.services.openapi.apache.core.OpenApiRequestException;
+import com.sap.cloud.sdk.services.openapi.apache.core.OpenApiResponse;
+import com.sap.cloud.sdk.services.openapi.apache.apiclient.ApiClient;
+import com.sap.cloud.sdk.services.openapi.apache.apiclient.BaseApi;
+import com.sap.cloud.sdk.services.openapi.apache.apiclient.Pair;
+
+
+import com.sap.cloud.sdk.datamodel.rest.test.model.Soda;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.StringJoiner;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+import com.sap.cloud.sdk.cloudplatform.connectivity.Destination;
+
+
+/**
+ * OAS 3.1 Nullable $ref via anyOf in version 1.0.0.
+ * <p>
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ */
+public class DefaultApi extends BaseApi {
+
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.1 Nullable $ref via anyOf.
+     *
+     * @param httpDestination The destination that API should be used with
+     */
+    public DefaultApi( @Nonnull final Destination httpDestination )
+    {
+    super(httpDestination);
+    }
+
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.1 Nullable $ref via anyOf based on a given {@link ApiClient}.
+     *
+     * @param apiClient
+     *            ApiClient to invoke the API on
+     */
+    public DefaultApi(@Nonnull final ApiClient apiClient) {
+    super(apiClient);
+    }
+
+    /**
+    * Creates a new API instance with additional default headers.
+    *
+    * @param defaultHeaders Additional headers to include in all requests
+    * @return A new API instance with the combined headers
+    */
+    public DefaultApi withDefaultHeaders(@Nonnull final Map<String, String> defaultHeaders) {
+        final var api = new DefaultApi(apiClient);
+        api.defaultHeaders.putAll(this.defaultHeaders);
+        api.defaultHeaders.putAll(defaultHeaders);
+        return api;
+    }
+
+
+        /**
+         * <p>
+         * <p>
+         * <p><b>200</b> - A soda
+         * @return Soda
+         * @throws OpenApiRequestException if an error occurs while attempting to invoke the API
+         */
+        @Nonnull
+        public Soda getSodas() throws OpenApiRequestException {
+            
+            // create path and map variables
+            final String localVarPath = "/sodas";
+            
+            final StringJoiner localVarQueryStringJoiner = new StringJoiner("&");
+            final List<Pair> localVarQueryParams = new ArrayList<Pair>();
+            final List<Pair> localVarCollectionQueryParams = new ArrayList<Pair>();
+            final Map<String, String> localVarHeaderParams = new HashMap<String, String>(defaultHeaders);
+            final Map<String, Object> localVarFormParams = new HashMap<String, Object>();
+            
+                                    
+            final String[] localVarAccepts = {
+            "application/json"
+            };
+            final String localVarAccept = ApiClient.selectHeaderAccept(localVarAccepts);
+            final String[] localVarContentTypes = {
+            
+            };
+            final String localVarContentType = ApiClient.selectHeaderContentType(localVarContentTypes);
+            
+            final TypeReference<Soda> localVarReturnType = new TypeReference<Soda>() {};
+                        
+            return apiClient.invokeAPI(
+                localVarPath,
+                "GET",
+                localVarQueryParams,
+                localVarCollectionQueryParams,
+                localVarQueryStringJoiner.toString(),
+                null,
+                localVarHeaderParams,
+                localVarFormParams,
+                localVarAccept,
+                localVarContentType,
+                localVarReturnType
+            );
+        }
+        }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-nullable-ref/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-nullable-ref/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
new file mode 100644
index 0000000000..7468af81f2
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-nullable-ref/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
@@ -0,0 +1,209 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+/*
+ * OAS 3.1 Nullable $ref via anyOf
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonValue;
+import com.sap.cloud.sdk.datamodel.rest.test.model.SodaCategory;
+import com.fasterxml.jackson.annotation.JsonAnySetter;
+import com.fasterxml.jackson.annotation.JsonAnyGetter;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * Soda
+ */
+// CHECKSTYLE:OFF
+public class Soda 
+// CHECKSTYLE:ON
+{
+  @JsonProperty("name")
+  private String name;
+
+  @JsonProperty("category")
+  private SodaCategory category;
+
+  @JsonAnySetter
+  @JsonAnyGetter
+  private final Map<String, Object> cloudSdkCustomFields = new LinkedHashMap<>();
+
+  /**
+   * Set the name of this {@link Soda} instance and return the same instance.
+   *
+   * @param name  The name of this {@link Soda}
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda name( @Nonnull final String name) {
+    this.name = name;
+    return this;
+  }
+
+  /**
+   * Get name
+   * @return name  The name of this {@link Soda} instance.
+   */
+  @Nonnull
+  public String getName() {
+    return name;
+  }
+
+  /**
+   * Set the name of this {@link Soda} instance.
+   *
+   * @param name  The name of this {@link Soda}
+   */
+  public void setName( @Nonnull final String name) {
+    this.name = name;
+  }
+
+  /**
+   * Set the category of this {@link Soda} instance and return the same instance.
+   *
+   * @param category  The category of this {@link Soda}
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda category( @Nullable final SodaCategory category) {
+    this.category = category;
+    return this;
+  }
+
+  /**
+   * Get category
+   * @return category  The category of this {@link Soda} instance.
+   */
+  @Nullable
+  public SodaCategory getCategory() {
+    return category;
+  }
+
+  /**
+   * Set the category of this {@link Soda} instance.
+   *
+   * @param category  The category of this {@link Soda}
+   */
+  public void setCategory( @Nullable final SodaCategory category) {
+    this.category = category;
+  }
+
+  /**
+   * Get the names of the unrecognizable properties of the {@link Soda}.
+   * @return The set of properties names
+   */
+  @JsonIgnore
+  @Nonnull
+  public Set<String> getCustomFieldNames() {
+    return cloudSdkCustomFields.keySet();
+  }
+
+  /**
+   * Get the value of an unrecognizable property of this {@link Soda} instance.
+   * @deprecated Use {@link #toMap()} instead.
+   * @param name  The name of the property
+   * @return The value of the property
+   * @throws NoSuchElementException  If no property with the given name could be found.
+   */
+  @Nullable
+  @Deprecated
+  public Object getCustomField( @Nonnull final String name ) throws NoSuchElementException {
+    if( !cloudSdkCustomFields.containsKey(name) ) {
+        throw new NoSuchElementException("Soda has no field with name '" + name + "'.");
+    }
+    return cloudSdkCustomFields.get(name);
+  }
+
+  /**
+   * Get the value of all properties of this {@link Soda} instance including unrecognized properties.
+   *
+   * @return The map of all properties
+   */
+  @JsonIgnore
+  @Nonnull
+  public Map<String, Object> toMap()
+  {
+    final Map<String, Object> declaredFields = new LinkedHashMap<>(cloudSdkCustomFields);
+    if( name != null ) declaredFields.put("name", name);
+    if( category != null ) declaredFields.put("category", category);
+    return declaredFields;
+  }
+
+  /**
+   * Set an unrecognizable property of this {@link Soda} instance. If the map previously contained a mapping
+   * for the key, the old value is replaced by the specified value.
+   * @param customFieldName The name of the property
+   * @param customFieldValue The value of the property
+   */
+  @JsonIgnore
+  public void setCustomField( @Nonnull String customFieldName, @Nullable Object customFieldValue )
+  {
+      cloudSdkCustomFields.put(customFieldName, customFieldValue);
+  }
+
+
+  @Override
+  public boolean equals(@Nullable final java.lang.Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    final Soda soda = (Soda) o;
+    return Objects.equals(this.cloudSdkCustomFields, soda.cloudSdkCustomFields) &&
+        Objects.equals(this.name, soda.name) &&
+        Objects.equals(this.category, soda.category);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(name, category, cloudSdkCustomFields);
+  }
+
+  @Override
+  @Nonnull public String toString() {
+    final StringBuilder sb = new StringBuilder();
+    sb.append("class Soda {\n");
+    sb.append("    name: ").append(toIndentedString(name)).append("\n");
+    sb.append("    category: ").append(toIndentedString(category)).append("\n");
+    cloudSdkCustomFields.forEach((k,v) -> sb.append("    ").append(k).append(": ").append(toIndentedString(v)).append("\n"));
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(final java.lang.Object o) {
+    if (o == null) {
+      return "null";
+    }
+    return o.toString().replace("\n", "\n    ");
+  }
+
+}
+
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-nullable-ref/output/com/sap/cloud/sdk/datamodel/rest/test/model/SodaCategory.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-nullable-ref/output/com/sap/cloud/sdk/datamodel/rest/test/model/SodaCategory.java
new file mode 100644
index 0000000000..90e9cc5959
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-nullable-ref/output/com/sap/cloud/sdk/datamodel/rest/test/model/SodaCategory.java
@@ -0,0 +1,173 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+/*
+ * OAS 3.1 Nullable $ref via anyOf
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonValue;
+import com.fasterxml.jackson.annotation.JsonAnySetter;
+import com.fasterxml.jackson.annotation.JsonAnyGetter;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * SodaCategory
+ */
+// CHECKSTYLE:OFF
+public class SodaCategory 
+// CHECKSTYLE:ON
+{
+  @JsonProperty("name")
+  private String name;
+
+  @JsonAnySetter
+  @JsonAnyGetter
+  private final Map<String, Object> cloudSdkCustomFields = new LinkedHashMap<>();
+
+  /**
+   * Set the name of this {@link SodaCategory} instance and return the same instance.
+   *
+   * @param name  The name of this {@link SodaCategory}
+   * @return The same instance of this {@link SodaCategory} class
+   */
+  @Nonnull public SodaCategory name( @Nullable final String name) {
+    this.name = name;
+    return this;
+  }
+
+  /**
+   * Get name
+   * @return name  The name of this {@link SodaCategory} instance.
+   */
+  @Nonnull
+  public String getName() {
+    return name;
+  }
+
+  /**
+   * Set the name of this {@link SodaCategory} instance.
+   *
+   * @param name  The name of this {@link SodaCategory}
+   */
+  public void setName( @Nullable final String name) {
+    this.name = name;
+  }
+
+  /**
+   * Get the names of the unrecognizable properties of the {@link SodaCategory}.
+   * @return The set of properties names
+   */
+  @JsonIgnore
+  @Nonnull
+  public Set<String> getCustomFieldNames() {
+    return cloudSdkCustomFields.keySet();
+  }
+
+  /**
+   * Get the value of an unrecognizable property of this {@link SodaCategory} instance.
+   * @deprecated Use {@link #toMap()} instead.
+   * @param name  The name of the property
+   * @return The value of the property
+   * @throws NoSuchElementException  If no property with the given name could be found.
+   */
+  @Nullable
+  @Deprecated
+  public Object getCustomField( @Nonnull final String name ) throws NoSuchElementException {
+    if( !cloudSdkCustomFields.containsKey(name) ) {
+        throw new NoSuchElementException("SodaCategory has no field with name '" + name + "'.");
+    }
+    return cloudSdkCustomFields.get(name);
+  }
+
+  /**
+   * Get the value of all properties of this {@link SodaCategory} instance including unrecognized properties.
+   *
+   * @return The map of all properties
+   */
+  @JsonIgnore
+  @Nonnull
+  public Map<String, Object> toMap()
+  {
+    final Map<String, Object> declaredFields = new LinkedHashMap<>(cloudSdkCustomFields);
+    if( name != null ) declaredFields.put("name", name);
+    return declaredFields;
+  }
+
+  /**
+   * Set an unrecognizable property of this {@link SodaCategory} instance. If the map previously contained a mapping
+   * for the key, the old value is replaced by the specified value.
+   * @param customFieldName The name of the property
+   * @param customFieldValue The value of the property
+   */
+  @JsonIgnore
+  public void setCustomField( @Nonnull String customFieldName, @Nullable Object customFieldValue )
+  {
+      cloudSdkCustomFields.put(customFieldName, customFieldValue);
+  }
+
+
+  @Override
+  public boolean equals(@Nullable final java.lang.Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    final SodaCategory sodaCategory = (SodaCategory) o;
+    return Objects.equals(this.cloudSdkCustomFields, sodaCategory.cloudSdkCustomFields) &&
+        Objects.equals(this.name, sodaCategory.name);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(name, cloudSdkCustomFields);
+  }
+
+  @Override
+  @Nonnull public String toString() {
+    final StringBuilder sb = new StringBuilder();
+    sb.append("class SodaCategory {\n");
+    sb.append("    name: ").append(toIndentedString(name)).append("\n");
+    cloudSdkCustomFields.forEach((k,v) -> sb.append("    ").append(k).append(": ").append(toIndentedString(v)).append("\n"));
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(final java.lang.Object o) {
+    if (o == null) {
+      return "null";
+    }
+    return o.toString().replace("\n", "\n    ");
+  }
+
+}
+
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-nullable-type-array/input/sodastore.yaml b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-nullable-type-array/input/sodastore.yaml
new file mode 100644
index 0000000000..c31da5b707
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-nullable-type-array/input/sodastore.yaml
@@ -0,0 +1,31 @@
+openapi: 3.1.0
+info:
+  title: OAS 3.1 Nullable Type Array
+  version: 1.0.0
+
+paths:
+  /sodas:
+    get:
+      operationId: getSodas
+      responses:
+        '200':
+          description: A soda
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Soda'
+
+components:
+  schemas:
+    Soda:
+      type: object
+      properties:
+        name:
+          type: string
+        brand:
+          # nullable via type array instead of nullable: true
+          type:
+            - string
+            - "null"
+      required:
+        - name
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-nullable-type-array/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-nullable-type-array/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
new file mode 100644
index 0000000000..7c74b39ef6
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-nullable-type-array/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.api;
+
+import com.fasterxml.jackson.core.type.TypeReference;
+
+import com.sap.cloud.sdk.services.openapi.apache.core.OpenApiRequestException;
+import com.sap.cloud.sdk.services.openapi.apache.core.OpenApiResponse;
+import com.sap.cloud.sdk.services.openapi.apache.apiclient.ApiClient;
+import com.sap.cloud.sdk.services.openapi.apache.apiclient.BaseApi;
+import com.sap.cloud.sdk.services.openapi.apache.apiclient.Pair;
+
+
+import com.sap.cloud.sdk.datamodel.rest.test.model.Soda;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.StringJoiner;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+import com.sap.cloud.sdk.cloudplatform.connectivity.Destination;
+
+
+/**
+ * OAS 3.1 Nullable Type Array in version 1.0.0.
+ * <p>
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ */
+public class DefaultApi extends BaseApi {
+
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.1 Nullable Type Array.
+     *
+     * @param httpDestination The destination that API should be used with
+     */
+    public DefaultApi( @Nonnull final Destination httpDestination )
+    {
+    super(httpDestination);
+    }
+
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.1 Nullable Type Array based on a given {@link ApiClient}.
+     *
+     * @param apiClient
+     *            ApiClient to invoke the API on
+     */
+    public DefaultApi(@Nonnull final ApiClient apiClient) {
+    super(apiClient);
+    }
+
+    /**
+    * Creates a new API instance with additional default headers.
+    *
+    * @param defaultHeaders Additional headers to include in all requests
+    * @return A new API instance with the combined headers
+    */
+    public DefaultApi withDefaultHeaders(@Nonnull final Map<String, String> defaultHeaders) {
+        final var api = new DefaultApi(apiClient);
+        api.defaultHeaders.putAll(this.defaultHeaders);
+        api.defaultHeaders.putAll(defaultHeaders);
+        return api;
+    }
+
+
+        /**
+         * <p>
+         * <p>
+         * <p><b>200</b> - A soda
+         * @return Soda
+         * @throws OpenApiRequestException if an error occurs while attempting to invoke the API
+         */
+        @Nonnull
+        public Soda getSodas() throws OpenApiRequestException {
+            
+            // create path and map variables
+            final String localVarPath = "/sodas";
+            
+            final StringJoiner localVarQueryStringJoiner = new StringJoiner("&");
+            final List<Pair> localVarQueryParams = new ArrayList<Pair>();
+            final List<Pair> localVarCollectionQueryParams = new ArrayList<Pair>();
+            final Map<String, String> localVarHeaderParams = new HashMap<String, String>(defaultHeaders);
+            final Map<String, Object> localVarFormParams = new HashMap<String, Object>();
+            
+                                    
+            final String[] localVarAccepts = {
+            "application/json"
+            };
+            final String localVarAccept = ApiClient.selectHeaderAccept(localVarAccepts);
+            final String[] localVarContentTypes = {
+            
+            };
+            final String localVarContentType = ApiClient.selectHeaderContentType(localVarContentTypes);
+            
+            final TypeReference<Soda> localVarReturnType = new TypeReference<Soda>() {};
+                        
+            return apiClient.invokeAPI(
+                localVarPath,
+                "GET",
+                localVarQueryParams,
+                localVarCollectionQueryParams,
+                localVarQueryStringJoiner.toString(),
+                null,
+                localVarHeaderParams,
+                localVarFormParams,
+                localVarAccept,
+                localVarContentType,
+                localVarReturnType
+            );
+        }
+        }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-nullable-type-array/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-nullable-type-array/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
new file mode 100644
index 0000000000..5b36050103
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-nullable-type-array/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
@@ -0,0 +1,208 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+/*
+ * OAS 3.1 Nullable Type Array
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonValue;
+import com.fasterxml.jackson.annotation.JsonAnySetter;
+import com.fasterxml.jackson.annotation.JsonAnyGetter;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * Soda
+ */
+// CHECKSTYLE:OFF
+public class Soda 
+// CHECKSTYLE:ON
+{
+  @JsonProperty("name")
+  private String name;
+
+  @JsonProperty("brand")
+  private String brand;
+
+  @JsonAnySetter
+  @JsonAnyGetter
+  private final Map<String, Object> cloudSdkCustomFields = new LinkedHashMap<>();
+
+  /**
+   * Set the name of this {@link Soda} instance and return the same instance.
+   *
+   * @param name  The name of this {@link Soda}
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda name( @Nonnull final String name) {
+    this.name = name;
+    return this;
+  }
+
+  /**
+   * Get name
+   * @return name  The name of this {@link Soda} instance.
+   */
+  @Nonnull
+  public String getName() {
+    return name;
+  }
+
+  /**
+   * Set the name of this {@link Soda} instance.
+   *
+   * @param name  The name of this {@link Soda}
+   */
+  public void setName( @Nonnull final String name) {
+    this.name = name;
+  }
+
+  /**
+   * Set the brand of this {@link Soda} instance and return the same instance.
+   *
+   * @param brand  The brand of this {@link Soda}
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda brand( @Nullable final String brand) {
+    this.brand = brand;
+    return this;
+  }
+
+  /**
+   * Get brand
+   * @return brand  The brand of this {@link Soda} instance.
+   */
+  @Nullable
+  public String getBrand() {
+    return brand;
+  }
+
+  /**
+   * Set the brand of this {@link Soda} instance.
+   *
+   * @param brand  The brand of this {@link Soda}
+   */
+  public void setBrand( @Nullable final String brand) {
+    this.brand = brand;
+  }
+
+  /**
+   * Get the names of the unrecognizable properties of the {@link Soda}.
+   * @return The set of properties names
+   */
+  @JsonIgnore
+  @Nonnull
+  public Set<String> getCustomFieldNames() {
+    return cloudSdkCustomFields.keySet();
+  }
+
+  /**
+   * Get the value of an unrecognizable property of this {@link Soda} instance.
+   * @deprecated Use {@link #toMap()} instead.
+   * @param name  The name of the property
+   * @return The value of the property
+   * @throws NoSuchElementException  If no property with the given name could be found.
+   */
+  @Nullable
+  @Deprecated
+  public Object getCustomField( @Nonnull final String name ) throws NoSuchElementException {
+    if( !cloudSdkCustomFields.containsKey(name) ) {
+        throw new NoSuchElementException("Soda has no field with name '" + name + "'.");
+    }
+    return cloudSdkCustomFields.get(name);
+  }
+
+  /**
+   * Get the value of all properties of this {@link Soda} instance including unrecognized properties.
+   *
+   * @return The map of all properties
+   */
+  @JsonIgnore
+  @Nonnull
+  public Map<String, Object> toMap()
+  {
+    final Map<String, Object> declaredFields = new LinkedHashMap<>(cloudSdkCustomFields);
+    if( name != null ) declaredFields.put("name", name);
+    if( brand != null ) declaredFields.put("brand", brand);
+    return declaredFields;
+  }
+
+  /**
+   * Set an unrecognizable property of this {@link Soda} instance. If the map previously contained a mapping
+   * for the key, the old value is replaced by the specified value.
+   * @param customFieldName The name of the property
+   * @param customFieldValue The value of the property
+   */
+  @JsonIgnore
+  public void setCustomField( @Nonnull String customFieldName, @Nullable Object customFieldValue )
+  {
+      cloudSdkCustomFields.put(customFieldName, customFieldValue);
+  }
+
+
+  @Override
+  public boolean equals(@Nullable final java.lang.Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    final Soda soda = (Soda) o;
+    return Objects.equals(this.cloudSdkCustomFields, soda.cloudSdkCustomFields) &&
+        Objects.equals(this.name, soda.name) &&
+        Objects.equals(this.brand, soda.brand);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(name, brand, cloudSdkCustomFields);
+  }
+
+  @Override
+  @Nonnull public String toString() {
+    final StringBuilder sb = new StringBuilder();
+    sb.append("class Soda {\n");
+    sb.append("    name: ").append(toIndentedString(name)).append("\n");
+    sb.append("    brand: ").append(toIndentedString(brand)).append("\n");
+    cloudSdkCustomFields.forEach((k,v) -> sb.append("    ").append(k).append(": ").append(toIndentedString(v)).append("\n"));
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(final java.lang.Object o) {
+    if (o == null) {
+      return "null";
+    }
+    return o.toString().replace("\n", "\n    ");
+  }
+
+}
+
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-ref-with-sibling/input/sodastore.yaml b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-ref-with-sibling/input/sodastore.yaml
new file mode 100644
index 0000000000..081c006624
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-ref-with-sibling/input/sodastore.yaml
@@ -0,0 +1,34 @@
+openapi: 3.1.0
+info:
+  title: OAS 3.1 $ref with Sibling Properties
+  version: 1.0.0
+
+paths:
+  /sodas:
+    get:
+      operationId: getSodas
+      responses:
+        '200':
+          description: A soda
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Soda'
+
+components:
+  schemas:
+    SodaDescription:
+      type: string
+      description: Soda description
+
+    Soda:
+      type: object
+      properties:
+        name:
+          type: string
+        description:
+          # $ref with a sibling property — valid in OAS 3.1
+          $ref: '#/components/schemas/SodaDescription'
+          description: Soda description as part of the Soda object
+      required:
+        - name
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-ref-with-sibling/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-ref-with-sibling/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
new file mode 100644
index 0000000000..fdf9fb8654
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-ref-with-sibling/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.api;
+
+import com.fasterxml.jackson.core.type.TypeReference;
+
+import com.sap.cloud.sdk.services.openapi.apache.core.OpenApiRequestException;
+import com.sap.cloud.sdk.services.openapi.apache.core.OpenApiResponse;
+import com.sap.cloud.sdk.services.openapi.apache.apiclient.ApiClient;
+import com.sap.cloud.sdk.services.openapi.apache.apiclient.BaseApi;
+import com.sap.cloud.sdk.services.openapi.apache.apiclient.Pair;
+
+
+import com.sap.cloud.sdk.datamodel.rest.test.model.Soda;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.StringJoiner;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+import com.sap.cloud.sdk.cloudplatform.connectivity.Destination;
+
+
+/**
+ * OAS 3.1 $ref with Sibling Properties in version 1.0.0.
+ * <p>
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ */
+public class DefaultApi extends BaseApi {
+
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.1 $ref with Sibling Properties.
+     *
+     * @param httpDestination The destination that API should be used with
+     */
+    public DefaultApi( @Nonnull final Destination httpDestination )
+    {
+    super(httpDestination);
+    }
+
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.1 $ref with Sibling Properties based on a given {@link ApiClient}.
+     *
+     * @param apiClient
+     *            ApiClient to invoke the API on
+     */
+    public DefaultApi(@Nonnull final ApiClient apiClient) {
+    super(apiClient);
+    }
+
+    /**
+    * Creates a new API instance with additional default headers.
+    *
+    * @param defaultHeaders Additional headers to include in all requests
+    * @return A new API instance with the combined headers
+    */
+    public DefaultApi withDefaultHeaders(@Nonnull final Map<String, String> defaultHeaders) {
+        final var api = new DefaultApi(apiClient);
+        api.defaultHeaders.putAll(this.defaultHeaders);
+        api.defaultHeaders.putAll(defaultHeaders);
+        return api;
+    }
+
+
+        /**
+         * <p>
+         * <p>
+         * <p><b>200</b> - A soda
+         * @return Soda
+         * @throws OpenApiRequestException if an error occurs while attempting to invoke the API
+         */
+        @Nonnull
+        public Soda getSodas() throws OpenApiRequestException {
+            
+            // create path and map variables
+            final String localVarPath = "/sodas";
+            
+            final StringJoiner localVarQueryStringJoiner = new StringJoiner("&");
+            final List<Pair> localVarQueryParams = new ArrayList<Pair>();
+            final List<Pair> localVarCollectionQueryParams = new ArrayList<Pair>();
+            final Map<String, String> localVarHeaderParams = new HashMap<String, String>(defaultHeaders);
+            final Map<String, Object> localVarFormParams = new HashMap<String, Object>();
+            
+                                    
+            final String[] localVarAccepts = {
+            "application/json"
+            };
+            final String localVarAccept = ApiClient.selectHeaderAccept(localVarAccepts);
+            final String[] localVarContentTypes = {
+            
+            };
+            final String localVarContentType = ApiClient.selectHeaderContentType(localVarContentTypes);
+            
+            final TypeReference<Soda> localVarReturnType = new TypeReference<Soda>() {};
+                        
+            return apiClient.invokeAPI(
+                localVarPath,
+                "GET",
+                localVarQueryParams,
+                localVarCollectionQueryParams,
+                localVarQueryStringJoiner.toString(),
+                null,
+                localVarHeaderParams,
+                localVarFormParams,
+                localVarAccept,
+                localVarContentType,
+                localVarReturnType
+            );
+        }
+        }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-ref-with-sibling/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-ref-with-sibling/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
new file mode 100644
index 0000000000..d88df9c21b
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorApacheIntegrationTest/oas31-ref-with-sibling/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
@@ -0,0 +1,208 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+/*
+ * OAS 3.1 $ref with Sibling Properties
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonValue;
+import com.fasterxml.jackson.annotation.JsonAnySetter;
+import com.fasterxml.jackson.annotation.JsonAnyGetter;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * Soda
+ */
+// CHECKSTYLE:OFF
+public class Soda 
+// CHECKSTYLE:ON
+{
+  @JsonProperty("name")
+  private String name;
+
+  @JsonProperty("description")
+  private String description;
+
+  @JsonAnySetter
+  @JsonAnyGetter
+  private final Map<String, Object> cloudSdkCustomFields = new LinkedHashMap<>();
+
+  /**
+   * Set the name of this {@link Soda} instance and return the same instance.
+   *
+   * @param name  The name of this {@link Soda}
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda name( @Nonnull final String name) {
+    this.name = name;
+    return this;
+  }
+
+  /**
+   * Get name
+   * @return name  The name of this {@link Soda} instance.
+   */
+  @Nonnull
+  public String getName() {
+    return name;
+  }
+
+  /**
+   * Set the name of this {@link Soda} instance.
+   *
+   * @param name  The name of this {@link Soda}
+   */
+  public void setName( @Nonnull final String name) {
+    this.name = name;
+  }
+
+  /**
+   * Set the description of this {@link Soda} instance and return the same instance.
+   *
+   * @param description  The description of this {@link Soda}
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda description( @Nullable final String description) {
+    this.description = description;
+    return this;
+  }
+
+  /**
+   * Get description
+   * @return description  The description of this {@link Soda} instance.
+   */
+  @Nonnull
+  public String getDescription() {
+    return description;
+  }
+
+  /**
+   * Set the description of this {@link Soda} instance.
+   *
+   * @param description  The description of this {@link Soda}
+   */
+  public void setDescription( @Nullable final String description) {
+    this.description = description;
+  }
+
+  /**
+   * Get the names of the unrecognizable properties of the {@link Soda}.
+   * @return The set of properties names
+   */
+  @JsonIgnore
+  @Nonnull
+  public Set<String> getCustomFieldNames() {
+    return cloudSdkCustomFields.keySet();
+  }
+
+  /**
+   * Get the value of an unrecognizable property of this {@link Soda} instance.
+   * @deprecated Use {@link #toMap()} instead.
+   * @param name  The name of the property
+   * @return The value of the property
+   * @throws NoSuchElementException  If no property with the given name could be found.
+   */
+  @Nullable
+  @Deprecated
+  public Object getCustomField( @Nonnull final String name ) throws NoSuchElementException {
+    if( !cloudSdkCustomFields.containsKey(name) ) {
+        throw new NoSuchElementException("Soda has no field with name '" + name + "'.");
+    }
+    return cloudSdkCustomFields.get(name);
+  }
+
+  /**
+   * Get the value of all properties of this {@link Soda} instance including unrecognized properties.
+   *
+   * @return The map of all properties
+   */
+  @JsonIgnore
+  @Nonnull
+  public Map<String, Object> toMap()
+  {
+    final Map<String, Object> declaredFields = new LinkedHashMap<>(cloudSdkCustomFields);
+    if( name != null ) declaredFields.put("name", name);
+    if( description != null ) declaredFields.put("description", description);
+    return declaredFields;
+  }
+
+  /**
+   * Set an unrecognizable property of this {@link Soda} instance. If the map previously contained a mapping
+   * for the key, the old value is replaced by the specified value.
+   * @param customFieldName The name of the property
+   * @param customFieldValue The value of the property
+   */
+  @JsonIgnore
+  public void setCustomField( @Nonnull String customFieldName, @Nullable Object customFieldValue )
+  {
+      cloudSdkCustomFields.put(customFieldName, customFieldValue);
+  }
+
+
+  @Override
+  public boolean equals(@Nullable final java.lang.Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    final Soda soda = (Soda) o;
+    return Objects.equals(this.cloudSdkCustomFields, soda.cloudSdkCustomFields) &&
+        Objects.equals(this.name, soda.name) &&
+        Objects.equals(this.description, soda.description);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(name, description, cloudSdkCustomFields);
+  }
+
+  @Override
+  @Nonnull public String toString() {
+    final StringBuilder sb = new StringBuilder();
+    sb.append("class Soda {\n");
+    sb.append("    name: ").append(toIndentedString(name)).append("\n");
+    sb.append("    description: ").append(toIndentedString(description)).append("\n");
+    cloudSdkCustomFields.forEach((k,v) -> sb.append("    ").append(k).append(": ").append(toIndentedString(v)).append("\n"));
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(final java.lang.Object o) {
+    if (o == null) {
+      return "null";
+    }
+    return o.toString().replace("\n", "\n    ");
+  }
+
+}
+
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-for-ai-sdk/output/com/sap/cloud/sdk/services/builder/model/NewSoda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-for-ai-sdk/output/com/sap/cloud/sdk/services/builder/model/NewSoda.java
index 20ce285d8a..9ca1d90b0d 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-for-ai-sdk/output/com/sap/cloud/sdk/services/builder/model/NewSoda.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-for-ai-sdk/output/com/sap/cloud/sdk/services/builder/model/NewSoda.java
@@ -137,7 +137,7 @@ public void setBrand( @Nonnull final String brand) {
    * Get zero
    * @return zero  The zero of this {@link NewSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public Boolean isZero() {
     return zero;
   }
@@ -166,7 +166,7 @@ public void setZero( @Nullable final Boolean zero) {
    * Get since
    * @return since  The since of this {@link NewSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public LocalDate getSince() {
     return since;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-for-ai-sdk/output/com/sap/cloud/sdk/services/builder/model/Soda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-for-ai-sdk/output/com/sap/cloud/sdk/services/builder/model/Soda.java
index b0cab12da7..9b0c569565 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-for-ai-sdk/output/com/sap/cloud/sdk/services/builder/model/Soda.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-for-ai-sdk/output/com/sap/cloud/sdk/services/builder/model/Soda.java
@@ -147,7 +147,7 @@ public enum DietEnum {
    * Get id
    * @return id  The id of this {@link Soda} instance.
    */
-  @Nonnull
+  @Nullable
   public Long getId() {
     return id;
   }
@@ -234,7 +234,7 @@ public void setBrand( @Nonnull final String brand) {
    * Get isAvailable
    * @return isAvailable  The isAvailable of this {@link Soda} instance.
    */
-  @Nonnull
+  @Nullable
   public Boolean isAvailable() {
     return isAvailable;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-for-ai-sdk/output/com/sap/cloud/sdk/services/builder/model/UpdateSoda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-for-ai-sdk/output/com/sap/cloud/sdk/services/builder/model/UpdateSoda.java
index 85f725e6ac..ee31eee5c3 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-for-ai-sdk/output/com/sap/cloud/sdk/services/builder/model/UpdateSoda.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-for-ai-sdk/output/com/sap/cloud/sdk/services/builder/model/UpdateSoda.java
@@ -79,7 +79,7 @@ public class UpdateSoda
    * Get name
    * @return name  The name of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public String getName() {
     return name;
   }
@@ -108,7 +108,7 @@ public void setName( @Nullable final String name) {
    * Get zero
    * @return zero  The zero of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public Boolean isZero() {
     return zero;
   }
@@ -137,7 +137,7 @@ public void setZero( @Nullable final Boolean zero) {
    * Get since
    * @return since  The since of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public LocalDate getSince() {
     return since;
   }
@@ -166,7 +166,7 @@ public void setSince( @Nullable final LocalDate since) {
    * Get brand
    * @return brand  The brand of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public String getBrand() {
     return brand;
   }
@@ -195,7 +195,7 @@ public void setBrand( @Nullable final String brand) {
    * Get flavor
    * @return flavor  The flavor of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public String getFlavor() {
     return flavor;
   }
@@ -224,7 +224,7 @@ public void setFlavor( @Nullable final String flavor) {
    * Get price
    * @return price  The price of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public Float getPrice() {
     return price;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-vendor-extension-json/output/com/sap/cloud/sdk/services/apiclassvendorextension/model/NewSoda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-vendor-extension-json/output/com/sap/cloud/sdk/services/apiclassvendorextension/model/NewSoda.java
index 6bbd8468d5..3741a02993 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-vendor-extension-json/output/com/sap/cloud/sdk/services/apiclassvendorextension/model/NewSoda.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-vendor-extension-json/output/com/sap/cloud/sdk/services/apiclassvendorextension/model/NewSoda.java
@@ -137,7 +137,7 @@ public void setBrand( @Nonnull final String brand) {
    * Get zero
    * @return zero  The zero of this {@link NewSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public Boolean isZero() {
     return zero;
   }
@@ -166,7 +166,7 @@ public void setZero( @Nullable final Boolean zero) {
    * Get since
    * @return since  The since of this {@link NewSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public LocalDate getSince() {
     return since;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-vendor-extension-json/output/com/sap/cloud/sdk/services/apiclassvendorextension/model/Soda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-vendor-extension-json/output/com/sap/cloud/sdk/services/apiclassvendorextension/model/Soda.java
index b0159f9aa3..3a972cbd9a 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-vendor-extension-json/output/com/sap/cloud/sdk/services/apiclassvendorextension/model/Soda.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-vendor-extension-json/output/com/sap/cloud/sdk/services/apiclassvendorextension/model/Soda.java
@@ -75,7 +75,7 @@ public class Soda
    * Get id
    * @return id  The id of this {@link Soda} instance.
    */
-  @Nonnull
+  @Nullable
   public Long getId() {
     return id;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-vendor-extension-json/output/com/sap/cloud/sdk/services/apiclassvendorextension/model/UpdateSoda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-vendor-extension-json/output/com/sap/cloud/sdk/services/apiclassvendorextension/model/UpdateSoda.java
index 65139c68cf..71fed98e84 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-vendor-extension-json/output/com/sap/cloud/sdk/services/apiclassvendorextension/model/UpdateSoda.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-vendor-extension-json/output/com/sap/cloud/sdk/services/apiclassvendorextension/model/UpdateSoda.java
@@ -79,7 +79,7 @@ public class UpdateSoda
    * Get name
    * @return name  The name of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public String getName() {
     return name;
   }
@@ -108,7 +108,7 @@ public void setName( @Nullable final String name) {
    * Get zero
    * @return zero  The zero of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public Boolean isZero() {
     return zero;
   }
@@ -137,7 +137,7 @@ public void setZero( @Nullable final Boolean zero) {
    * Get since
    * @return since  The since of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public LocalDate getSince() {
     return since;
   }
@@ -166,7 +166,7 @@ public void setSince( @Nullable final LocalDate since) {
    * Get brand
    * @return brand  The brand of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public String getBrand() {
     return brand;
   }
@@ -195,7 +195,7 @@ public void setBrand( @Nullable final String brand) {
    * Get flavor
    * @return flavor  The flavor of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public String getFlavor() {
     return flavor;
   }
@@ -224,7 +224,7 @@ public void setFlavor( @Nullable final String flavor) {
    * Get price
    * @return price  The price of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public Float getPrice() {
     return price;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-vendor-extension-yaml/output/com/sap/cloud/sdk/services/apiclassvendorextension/model/Soda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-vendor-extension-yaml/output/com/sap/cloud/sdk/services/apiclassvendorextension/model/Soda.java
index b0159f9aa3..3a972cbd9a 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-vendor-extension-yaml/output/com/sap/cloud/sdk/services/apiclassvendorextension/model/Soda.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-vendor-extension-yaml/output/com/sap/cloud/sdk/services/apiclassvendorextension/model/Soda.java
@@ -75,7 +75,7 @@ public class Soda
    * Get id
    * @return id  The id of this {@link Soda} instance.
    */
-  @Nonnull
+  @Nullable
   public Long getId() {
     return id;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-vendor-extension-yaml/output/com/sap/cloud/sdk/services/apiclassvendorextension/model/UpdateSoda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-vendor-extension-yaml/output/com/sap/cloud/sdk/services/apiclassvendorextension/model/UpdateSoda.java
index 84b275fbbc..af5a3bb907 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-vendor-extension-yaml/output/com/sap/cloud/sdk/services/apiclassvendorextension/model/UpdateSoda.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/api-class-vendor-extension-yaml/output/com/sap/cloud/sdk/services/apiclassvendorextension/model/UpdateSoda.java
@@ -72,7 +72,7 @@ public class UpdateSoda
    * Get name
    * @return name  The name of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public String getName() {
     return name;
   }
@@ -101,7 +101,7 @@ public void setName( @Nullable final String name) {
    * Get brand
    * @return brand  The brand of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public String getBrand() {
     return brand;
   }
@@ -130,7 +130,7 @@ public void setBrand( @Nullable final String brand) {
    * Get flavor
    * @return flavor  The flavor of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public String getFlavor() {
     return flavor;
   }
@@ -159,7 +159,7 @@ public void setFlavor( @Nullable final String flavor) {
    * Get price
    * @return price  The price of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public Float getPrice() {
     return price;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/AllOf.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/AllOf.java
index 9dfaf3ea30..acb1c546e2 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/AllOf.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/AllOf.java
@@ -63,7 +63,7 @@ public class AllOf
    * Get sodaType
    * @return sodaType  The sodaType of this {@link AllOf} instance.
    */
-  @Nonnull
+  @Nullable
   public String getSodaType() {
     return sodaType;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/AnyOf.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/AnyOf.java
index 59f1e77c07..caa2a6634d 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/AnyOf.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/AnyOf.java
@@ -65,7 +65,7 @@ public class AnyOf
    * Get sodaType
    * @return sodaType  The sodaType of this {@link AnyOf} instance.
    */
-  @Nonnull
+  @Nullable
   public String getSodaType() {
     return sodaType;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/Cola.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/Cola.java
index 523e3146a8..9bb0649a9e 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/Cola.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/Cola.java
@@ -63,7 +63,7 @@ public class Cola
    * Get sodaType
    * @return sodaType  The sodaType of this {@link Cola} instance.
    */
-  @Nonnull
+  @Nullable
   public String getSodaType() {
     return sodaType;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/Fanta.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/Fanta.java
index 349aeaae22..d017ff606b 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/Fanta.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/Fanta.java
@@ -63,7 +63,7 @@ public class Fanta
    * Get sodaType
    * @return sodaType  The sodaType of this {@link Fanta} instance.
    */
-  @Nonnull
+  @Nullable
   public String getSodaType() {
     return sodaType;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/OneOf.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/OneOf.java
index e41a7b7929..2d7585849f 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/OneOf.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/OneOf.java
@@ -65,7 +65,7 @@ public class OneOf
    * Get sodaType
    * @return sodaType  The sodaType of this {@link OneOf} instance.
    */
-  @Nonnull
+  @Nullable
   public String getSodaType() {
     return sodaType;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/OneOfWithDiscriminator.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/OneOfWithDiscriminator.java
index 5e2f1fc1cb..38866718d0 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/OneOfWithDiscriminator.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/OneOfWithDiscriminator.java
@@ -73,7 +73,7 @@ public class OneOfWithDiscriminator
    * Get sodaType
    * @return sodaType  The sodaType of this {@link OneOfWithDiscriminator} instance.
    */
-  @Nonnull
+  @Nullable
   public String getSodaType() {
     return sodaType;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/OneOfWithDiscriminatorAndMapping.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/OneOfWithDiscriminatorAndMapping.java
index 0fab43fec8..0003a28685 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/OneOfWithDiscriminatorAndMapping.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/generate-apis/output/test/OneOfWithDiscriminatorAndMapping.java
@@ -73,7 +73,7 @@ public class OneOfWithDiscriminatorAndMapping
    * Get sodaType
    * @return sodaType  The sodaType of this {@link OneOfWithDiscriminatorAndMapping} instance.
    */
-  @Nonnull
+  @Nullable
   public String getSodaType() {
     return sodaType;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/inlineobject-schemas-enabled/output/com/sap/cloud/sdk/services/inlineobject/model/NotFound.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/inlineobject-schemas-enabled/output/com/sap/cloud/sdk/services/inlineobject/model/NotFound.java
index d0893c9d66..e0f7e8920d 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/inlineobject-schemas-enabled/output/com/sap/cloud/sdk/services/inlineobject/model/NotFound.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/inlineobject-schemas-enabled/output/com/sap/cloud/sdk/services/inlineobject/model/NotFound.java
@@ -63,7 +63,7 @@ public class NotFound
    * Get message
    * @return message  The message of this {@link NotFound} instance.
    */
-  @Nonnull
+  @Nullable
   public String getMessage() {
     return message;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/inlineobject-schemas-enabled/output/com/sap/cloud/sdk/services/inlineobject/model/ServiceUnavailableApplicationJson.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/inlineobject-schemas-enabled/output/com/sap/cloud/sdk/services/inlineobject/model/ServiceUnavailableApplicationJson.java
index 2945b681ef..ebef35a00f 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/inlineobject-schemas-enabled/output/com/sap/cloud/sdk/services/inlineobject/model/ServiceUnavailableApplicationJson.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/inlineobject-schemas-enabled/output/com/sap/cloud/sdk/services/inlineobject/model/ServiceUnavailableApplicationJson.java
@@ -63,7 +63,7 @@ public class ServiceUnavailableApplicationJson
    * Get message
    * @return message  The message of this {@link ServiceUnavailableApplicationJson} instance.
    */
-  @Nonnull
+  @Nullable
   public String getMessage() {
     return message;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/inlineobject-schemas-enabled/output/com/sap/cloud/sdk/services/inlineobject/model/ServiceUnavailableApplicationXml.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/inlineobject-schemas-enabled/output/com/sap/cloud/sdk/services/inlineobject/model/ServiceUnavailableApplicationXml.java
index 7afdf67a4e..668d65cefd 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/inlineobject-schemas-enabled/output/com/sap/cloud/sdk/services/inlineobject/model/ServiceUnavailableApplicationXml.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/inlineobject-schemas-enabled/output/com/sap/cloud/sdk/services/inlineobject/model/ServiceUnavailableApplicationXml.java
@@ -63,7 +63,7 @@ public class ServiceUnavailableApplicationXml
    * Get message
    * @return message  The message of this {@link ServiceUnavailableApplicationXml} instance.
    */
-  @Nonnull
+  @Nullable
   public String getMessage() {
     return message;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/inlineobject-schemas-enabled/output/com/sap/cloud/sdk/services/inlineobject/model/Soda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/inlineobject-schemas-enabled/output/com/sap/cloud/sdk/services/inlineobject/model/Soda.java
index 542eb09b31..b02b6d497e 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/inlineobject-schemas-enabled/output/com/sap/cloud/sdk/services/inlineobject/model/Soda.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/inlineobject-schemas-enabled/output/com/sap/cloud/sdk/services/inlineobject/model/Soda.java
@@ -75,7 +75,7 @@ public class Soda
    * Get id
    * @return id  The id of this {@link Soda} instance.
    */
-  @Nonnull
+  @Nullable
   public Long getId() {
     return id;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/input-spec-with-builder/output/com/sap/cloud/sdk/services/builder/model/Soda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/input-spec-with-builder/output/com/sap/cloud/sdk/services/builder/model/Soda.java
index c9f6976f59..70d3713193 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/input-spec-with-builder/output/com/sap/cloud/sdk/services/builder/model/Soda.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/input-spec-with-builder/output/com/sap/cloud/sdk/services/builder/model/Soda.java
@@ -82,7 +82,7 @@ private Soda() {  }
    * Get id
    * @return id  The id of this {@link Soda} instance.
    */
-  @Nonnull
+  @Nullable
   public Long getId() {
     return id;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/input-spec-with-builder/output/com/sap/cloud/sdk/services/builder/model/UpdateSoda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/input-spec-with-builder/output/com/sap/cloud/sdk/services/builder/model/UpdateSoda.java
index 2dcad088ed..8bc477f584 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/input-spec-with-builder/output/com/sap/cloud/sdk/services/builder/model/UpdateSoda.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/input-spec-with-builder/output/com/sap/cloud/sdk/services/builder/model/UpdateSoda.java
@@ -76,7 +76,7 @@ private UpdateSoda() {  }
    * Get name
    * @return name  The name of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public String getName() {
     return name;
   }
@@ -105,7 +105,7 @@ public void setName( @Nullable final String name) {
    * Get brand
    * @return brand  The brand of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public String getBrand() {
     return brand;
   }
@@ -134,7 +134,7 @@ public void setBrand( @Nullable final String brand) {
    * Get flavor
    * @return flavor  The flavor of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public String getFlavor() {
     return flavor;
   }
@@ -163,7 +163,7 @@ public void setFlavor( @Nullable final String flavor) {
    * Get price
    * @return price  The price of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public Float getPrice() {
     return price;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/input-spec-with-uppercase-file-extension/output/com/sap/cloud/sdk/services/uppercasefileextension/model/Soda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/input-spec-with-uppercase-file-extension/output/com/sap/cloud/sdk/services/uppercasefileextension/model/Soda.java
index 2dd435030a..2ce9f75f01 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/input-spec-with-uppercase-file-extension/output/com/sap/cloud/sdk/services/uppercasefileextension/model/Soda.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/input-spec-with-uppercase-file-extension/output/com/sap/cloud/sdk/services/uppercasefileextension/model/Soda.java
@@ -75,7 +75,7 @@ public class Soda
    * Get id
    * @return id  The id of this {@link Soda} instance.
    */
-  @Nonnull
+  @Nullable
   public Long getId() {
     return id;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/input-spec-with-uppercase-file-extension/output/com/sap/cloud/sdk/services/uppercasefileextension/model/UpdateSoda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/input-spec-with-uppercase-file-extension/output/com/sap/cloud/sdk/services/uppercasefileextension/model/UpdateSoda.java
index f3a793b661..0083a0c344 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/input-spec-with-uppercase-file-extension/output/com/sap/cloud/sdk/services/uppercasefileextension/model/UpdateSoda.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/input-spec-with-uppercase-file-extension/output/com/sap/cloud/sdk/services/uppercasefileextension/model/UpdateSoda.java
@@ -72,7 +72,7 @@ public class UpdateSoda
    * Get name
    * @return name  The name of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public String getName() {
     return name;
   }
@@ -101,7 +101,7 @@ public void setName( @Nullable final String name) {
    * Get brand
    * @return brand  The brand of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public String getBrand() {
     return brand;
   }
@@ -130,7 +130,7 @@ public void setBrand( @Nullable final String brand) {
    * Get flavor
    * @return flavor  The flavor of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public String getFlavor() {
     return flavor;
   }
@@ -159,7 +159,7 @@ public void setFlavor( @Nullable final String flavor) {
    * Get price
    * @return price  The price of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public Float getPrice() {
     return price;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas30-exclusive-min-max/input/sodastore.yaml b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas30-exclusive-min-max/input/sodastore.yaml
new file mode 100644
index 0000000000..9ad45cbb3a
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas30-exclusive-min-max/input/sodastore.yaml
@@ -0,0 +1,38 @@
+openapi: 3.0.3
+info:
+  title: OAS 3.0 Boolean exclusiveMinimum and exclusiveMaximum
+  version: 1.0.0
+
+paths:
+  /sodas:
+    get:
+      operationId: getSodas
+      responses:
+        '200':
+          description: A soda
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Soda'
+
+components:
+  schemas:
+    Soda:
+      type: object
+      properties:
+        name:
+          type: string
+        rating:
+          # OAS 3.0: boolean exclusiveMinimum/exclusiveMaximum as flags alongside minimum/maximum
+          type: number
+          minimum: 0
+          exclusiveMinimum: true
+          maximum: 5
+          exclusiveMaximum: true
+        score:
+          # OAS 3.0: non-exclusive minimum/maximum (no boolean flags)
+          type: number
+          minimum: 0
+          maximum: 100
+      required:
+        - name
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas30-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas30-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
new file mode 100644
index 0000000000..09d8e0ade4
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas30-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.api;
+
+import com.sap.cloud.sdk.services.openapi.core.OpenApiRequestException;
+import com.sap.cloud.sdk.services.openapi.core.OpenApiResponse;
+import com.sap.cloud.sdk.services.openapi.core.AbstractOpenApiService;
+import com.sap.cloud.sdk.services.openapi.apiclient.ApiClient;
+
+import com.sap.cloud.sdk.datamodel.rest.test.model.Soda;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+
+import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.MultiValueMap;
+import org.springframework.web.util.UriComponentsBuilder;
+import org.springframework.core.ParameterizedTypeReference;
+import org.springframework.core.io.FileSystemResource;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.MediaType;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import com.google.common.annotations.Beta;
+
+import com.sap.cloud.sdk.cloudplatform.connectivity.Destination;
+
+/**
+ * OAS 3.0 Boolean exclusiveMinimum and exclusiveMaximum in version 1.0.0.
+ *
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ */
+public class DefaultApi extends AbstractOpenApiService {
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.0 Boolean exclusiveMinimum and exclusiveMaximum.
+     *
+     * @param httpDestination The destination that API should be used with
+     */
+    public DefaultApi( @Nonnull final Destination httpDestination )
+    {
+        super(httpDestination);
+    }
+
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.0 Boolean exclusiveMinimum and exclusiveMaximum based on a given {@link ApiClient}.
+     *
+     * @param apiClient
+     *            ApiClient to invoke the API on
+     */
+    @Beta
+    public DefaultApi( @Nonnull final ApiClient apiClient )
+    {
+         super(apiClient);
+    }
+
+        /**
+     * <p></p>
+     * <p></p>
+     * <p><b>200</b> - A soda
+     * @return Soda
+     * @throws OpenApiRequestException if an error occurs while attempting to invoke the API
+     */
+    @Nonnull
+    public Soda getSodas() throws OpenApiRequestException {
+        final Object localVarPostBody = null;
+        
+        final String localVarPath = UriComponentsBuilder.fromPath("/sodas").build().toUriString();
+
+        final MultiValueMap<String, String> localVarQueryParams = new LinkedMultiValueMap<String, String>();
+        final HttpHeaders localVarHeaderParams = new HttpHeaders();
+        final MultiValueMap<String, Object> localVarFormParams = new LinkedMultiValueMap<String, Object>();
+
+        final String[] localVarAccepts = { 
+            "application/json"
+        };
+        final List<MediaType> localVarAccept = apiClient.selectHeaderAccept(localVarAccepts);
+        final String[] localVarContentTypes = { };
+        final MediaType localVarContentType = apiClient.selectHeaderContentType(localVarContentTypes);
+
+        final String[] localVarAuthNames = new String[] {  };
+
+        final ParameterizedTypeReference<Soda> localVarReturnType = new ParameterizedTypeReference<Soda>() {};
+        return apiClient.invokeAPI(localVarPath, HttpMethod.GET, localVarQueryParams, localVarPostBody, localVarHeaderParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
+    }
+}
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas30-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas30-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
new file mode 100644
index 0000000000..f264eee8a8
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas30-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
@@ -0,0 +1,256 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+/*
+ * OAS 3.0 Boolean exclusiveMinimum and exclusiveMaximum
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonValue;
+import java.math.BigDecimal;
+import com.fasterxml.jackson.annotation.JsonAnySetter;
+import com.fasterxml.jackson.annotation.JsonAnyGetter;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * Soda
+ */
+// CHECKSTYLE:OFF
+public class Soda 
+// CHECKSTYLE:ON
+{
+  @JsonProperty("name")
+  private String name;
+
+  @JsonProperty("rating")
+  private BigDecimal rating;
+
+  @JsonProperty("score")
+  private BigDecimal score;
+
+  @JsonAnySetter
+  @JsonAnyGetter
+  private final Map<String, Object> cloudSdkCustomFields = new LinkedHashMap<>();
+
+  /**
+   * Set the name of this {@link Soda} instance and return the same instance.
+   *
+   * @param name  The name of this {@link Soda}
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda name( @Nonnull final String name) {
+    this.name = name;
+    return this;
+  }
+
+  /**
+   * Get name
+   * @return name  The name of this {@link Soda} instance.
+   */
+  @Nonnull
+  public String getName() {
+    return name;
+  }
+
+  /**
+   * Set the name of this {@link Soda} instance.
+   *
+   * @param name  The name of this {@link Soda}
+   */
+  public void setName( @Nonnull final String name) {
+    this.name = name;
+  }
+
+  /**
+   * Set the rating of this {@link Soda} instance and return the same instance.
+   *
+   * @param rating  The rating of this {@link Soda}
+   * Minimum: 0 (exclusive)
+   * Maximum: 5 (exclusive)
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda rating( @Nullable final BigDecimal rating) {
+    this.rating = rating;
+    return this;
+  }
+
+  /**
+   * Get rating
+   * minimum: 0 (exclusive)
+   * maximum: 5 (exclusive)
+   * @return rating  The rating of this {@link Soda} instance.
+   */
+  @Nullable
+  public BigDecimal getRating() {
+    return rating;
+  }
+
+  /**
+   * Set the rating of this {@link Soda} instance.
+   *
+   * @param rating  The rating of this {@link Soda}
+   * Minimum: 0 (exclusive)
+   * Maximum: 5 (exclusive)
+   */
+  public void setRating( @Nullable final BigDecimal rating) {
+    this.rating = rating;
+  }
+
+  /**
+   * Set the score of this {@link Soda} instance and return the same instance.
+   *
+   * @param score  The score of this {@link Soda}
+   * Minimum: 0
+   * Maximum: 100
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda score( @Nullable final BigDecimal score) {
+    this.score = score;
+    return this;
+  }
+
+  /**
+   * Get score
+   * minimum: 0
+   * maximum: 100
+   * @return score  The score of this {@link Soda} instance.
+   */
+  @Nullable
+  public BigDecimal getScore() {
+    return score;
+  }
+
+  /**
+   * Set the score of this {@link Soda} instance.
+   *
+   * @param score  The score of this {@link Soda}
+   * Minimum: 0
+   * Maximum: 100
+   */
+  public void setScore( @Nullable final BigDecimal score) {
+    this.score = score;
+  }
+
+  /**
+   * Get the names of the unrecognizable properties of the {@link Soda}.
+   * @return The set of properties names
+   */
+  @JsonIgnore
+  @Nonnull
+  public Set<String> getCustomFieldNames() {
+    return cloudSdkCustomFields.keySet();
+  }
+
+  /**
+   * Get the value of an unrecognizable property of this {@link Soda} instance.
+   * @deprecated Use {@link #toMap()} instead.
+   * @param name  The name of the property
+   * @return The value of the property
+   * @throws NoSuchElementException  If no property with the given name could be found.
+   */
+  @Nullable
+  @Deprecated
+  public Object getCustomField( @Nonnull final String name ) throws NoSuchElementException {
+    if( !cloudSdkCustomFields.containsKey(name) ) {
+        throw new NoSuchElementException("Soda has no field with name '" + name + "'.");
+    }
+    return cloudSdkCustomFields.get(name);
+  }
+
+  /**
+   * Get the value of all properties of this {@link Soda} instance including unrecognized properties.
+   *
+   * @return The map of all properties
+   */
+  @JsonIgnore
+  @Nonnull
+  public Map<String, Object> toMap()
+  {
+    final Map<String, Object> declaredFields = new LinkedHashMap<>(cloudSdkCustomFields);
+    if( name != null ) declaredFields.put("name", name);
+    if( rating != null ) declaredFields.put("rating", rating);
+    if( score != null ) declaredFields.put("score", score);
+    return declaredFields;
+  }
+
+  /**
+   * Set an unrecognizable property of this {@link Soda} instance. If the map previously contained a mapping
+   * for the key, the old value is replaced by the specified value.
+   * @param customFieldName The name of the property
+   * @param customFieldValue The value of the property
+   */
+  @JsonIgnore
+  public void setCustomField( @Nonnull String customFieldName, @Nullable Object customFieldValue )
+  {
+      cloudSdkCustomFields.put(customFieldName, customFieldValue);
+  }
+
+
+  @Override
+  public boolean equals(@Nullable final java.lang.Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    final Soda soda = (Soda) o;
+    return Objects.equals(this.cloudSdkCustomFields, soda.cloudSdkCustomFields) &&
+        Objects.equals(this.name, soda.name) &&
+        Objects.equals(this.rating, soda.rating) &&
+        Objects.equals(this.score, soda.score);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(name, rating, score, cloudSdkCustomFields);
+  }
+
+  @Override
+  @Nonnull public String toString() {
+    final StringBuilder sb = new StringBuilder();
+    sb.append("class Soda {\n");
+    sb.append("    name: ").append(toIndentedString(name)).append("\n");
+    sb.append("    rating: ").append(toIndentedString(rating)).append("\n");
+    sb.append("    score: ").append(toIndentedString(score)).append("\n");
+    cloudSdkCustomFields.forEach((k,v) -> sb.append("    ").append(k).append(": ").append(toIndentedString(v)).append("\n"));
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(final java.lang.Object o) {
+    if (o == null) {
+      return "null";
+    }
+    return o.toString().replace("\n", "\n    ");
+  }
+
+}
+
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-components-path-items/input/sodastore.yaml b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-components-path-items/input/sodastore.yaml
new file mode 100644
index 0000000000..0ea8f98073
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-components-path-items/input/sodastore.yaml
@@ -0,0 +1,49 @@
+openapi: 3.1.0
+info:
+  title: OAS 3.1 components/pathItems schema references
+  version: 1.0.0
+
+paths:
+  /sodas:
+    get:
+      operationId: getSodas
+      responses:
+        '200':
+          description: A soda
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Soda'
+
+components:
+  # OAS 3.1 adds components/pathItems — schemas referenced here must not be removed
+  pathItems:
+    sodaItem:
+      get:
+        operationId: getSodaDetail
+        responses:
+          '200':
+            description: success
+            content:
+              application/json:
+                schema:
+                  $ref: '#/components/schemas/SodaDetail'
+
+  schemas:
+    Soda:
+      type: object
+      properties:
+        name:
+          type: string
+    # Only referenced from components/pathItems, not from paths
+    SodaDetail:
+      type: object
+      properties:
+        description:
+          type: string
+    # Not referenced anywhere — should be removed by removeUnusedComponents
+    UnusedSchema:
+      type: object
+      properties:
+        garbage:
+          type: string
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-components-path-items/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-components-path-items/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
new file mode 100644
index 0000000000..ea68a69fa8
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-components-path-items/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.api;
+
+import com.sap.cloud.sdk.services.openapi.core.OpenApiRequestException;
+import com.sap.cloud.sdk.services.openapi.core.OpenApiResponse;
+import com.sap.cloud.sdk.services.openapi.core.AbstractOpenApiService;
+import com.sap.cloud.sdk.services.openapi.apiclient.ApiClient;
+
+import com.sap.cloud.sdk.datamodel.rest.test.model.Soda;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+
+import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.MultiValueMap;
+import org.springframework.web.util.UriComponentsBuilder;
+import org.springframework.core.ParameterizedTypeReference;
+import org.springframework.core.io.FileSystemResource;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.MediaType;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import com.google.common.annotations.Beta;
+
+import com.sap.cloud.sdk.cloudplatform.connectivity.Destination;
+
+/**
+ * OAS 3.1 components/pathItems schema references in version 1.0.0.
+ *
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ */
+public class DefaultApi extends AbstractOpenApiService {
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.1 components/pathItems schema references.
+     *
+     * @param httpDestination The destination that API should be used with
+     */
+    public DefaultApi( @Nonnull final Destination httpDestination )
+    {
+        super(httpDestination);
+    }
+
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.1 components/pathItems schema references based on a given {@link ApiClient}.
+     *
+     * @param apiClient
+     *            ApiClient to invoke the API on
+     */
+    @Beta
+    public DefaultApi( @Nonnull final ApiClient apiClient )
+    {
+         super(apiClient);
+    }
+
+        /**
+     * <p></p>
+     * <p></p>
+     * <p><b>200</b> - A soda
+     * @return Soda
+     * @throws OpenApiRequestException if an error occurs while attempting to invoke the API
+     */
+    @Nonnull
+    public Soda getSodas() throws OpenApiRequestException {
+        final Object localVarPostBody = null;
+        
+        final String localVarPath = UriComponentsBuilder.fromPath("/sodas").build().toUriString();
+
+        final MultiValueMap<String, String> localVarQueryParams = new LinkedMultiValueMap<String, String>();
+        final HttpHeaders localVarHeaderParams = new HttpHeaders();
+        final MultiValueMap<String, Object> localVarFormParams = new LinkedMultiValueMap<String, Object>();
+
+        final String[] localVarAccepts = { 
+            "application/json"
+        };
+        final List<MediaType> localVarAccept = apiClient.selectHeaderAccept(localVarAccepts);
+        final String[] localVarContentTypes = { };
+        final MediaType localVarContentType = apiClient.selectHeaderContentType(localVarContentTypes);
+
+        final String[] localVarAuthNames = new String[] {  };
+
+        final ParameterizedTypeReference<Soda> localVarReturnType = new ParameterizedTypeReference<Soda>() {};
+        return apiClient.invokeAPI(localVarPath, HttpMethod.GET, localVarQueryParams, localVarPostBody, localVarHeaderParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
+    }
+}
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-components-path-items/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-components-path-items/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
new file mode 100644
index 0000000000..211258b8b9
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-components-path-items/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
@@ -0,0 +1,173 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+/*
+ * OAS 3.1 components/pathItems schema references
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonValue;
+import com.fasterxml.jackson.annotation.JsonAnySetter;
+import com.fasterxml.jackson.annotation.JsonAnyGetter;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * Soda
+ */
+// CHECKSTYLE:OFF
+public class Soda 
+// CHECKSTYLE:ON
+{
+  @JsonProperty("name")
+  private String name;
+
+  @JsonAnySetter
+  @JsonAnyGetter
+  private final Map<String, Object> cloudSdkCustomFields = new LinkedHashMap<>();
+
+  /**
+   * Set the name of this {@link Soda} instance and return the same instance.
+   *
+   * @param name  The name of this {@link Soda}
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda name( @Nullable final String name) {
+    this.name = name;
+    return this;
+  }
+
+  /**
+   * Get name
+   * @return name  The name of this {@link Soda} instance.
+   */
+  @Nullable
+  public String getName() {
+    return name;
+  }
+
+  /**
+   * Set the name of this {@link Soda} instance.
+   *
+   * @param name  The name of this {@link Soda}
+   */
+  public void setName( @Nullable final String name) {
+    this.name = name;
+  }
+
+  /**
+   * Get the names of the unrecognizable properties of the {@link Soda}.
+   * @return The set of properties names
+   */
+  @JsonIgnore
+  @Nonnull
+  public Set<String> getCustomFieldNames() {
+    return cloudSdkCustomFields.keySet();
+  }
+
+  /**
+   * Get the value of an unrecognizable property of this {@link Soda} instance.
+   * @deprecated Use {@link #toMap()} instead.
+   * @param name  The name of the property
+   * @return The value of the property
+   * @throws NoSuchElementException  If no property with the given name could be found.
+   */
+  @Nullable
+  @Deprecated
+  public Object getCustomField( @Nonnull final String name ) throws NoSuchElementException {
+    if( !cloudSdkCustomFields.containsKey(name) ) {
+        throw new NoSuchElementException("Soda has no field with name '" + name + "'.");
+    }
+    return cloudSdkCustomFields.get(name);
+  }
+
+  /**
+   * Get the value of all properties of this {@link Soda} instance including unrecognized properties.
+   *
+   * @return The map of all properties
+   */
+  @JsonIgnore
+  @Nonnull
+  public Map<String, Object> toMap()
+  {
+    final Map<String, Object> declaredFields = new LinkedHashMap<>(cloudSdkCustomFields);
+    if( name != null ) declaredFields.put("name", name);
+    return declaredFields;
+  }
+
+  /**
+   * Set an unrecognizable property of this {@link Soda} instance. If the map previously contained a mapping
+   * for the key, the old value is replaced by the specified value.
+   * @param customFieldName The name of the property
+   * @param customFieldValue The value of the property
+   */
+  @JsonIgnore
+  public void setCustomField( @Nonnull String customFieldName, @Nullable Object customFieldValue )
+  {
+      cloudSdkCustomFields.put(customFieldName, customFieldValue);
+  }
+
+
+  @Override
+  public boolean equals(@Nullable final java.lang.Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    final Soda soda = (Soda) o;
+    return Objects.equals(this.cloudSdkCustomFields, soda.cloudSdkCustomFields) &&
+        Objects.equals(this.name, soda.name);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(name, cloudSdkCustomFields);
+  }
+
+  @Override
+  @Nonnull public String toString() {
+    final StringBuilder sb = new StringBuilder();
+    sb.append("class Soda {\n");
+    sb.append("    name: ").append(toIndentedString(name)).append("\n");
+    cloudSdkCustomFields.forEach((k,v) -> sb.append("    ").append(k).append(": ").append(toIndentedString(v)).append("\n"));
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(final java.lang.Object o) {
+    if (o == null) {
+      return "null";
+    }
+    return o.toString().replace("\n", "\n    ");
+  }
+
+}
+
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-components-path-items/output/com/sap/cloud/sdk/datamodel/rest/test/model/SodaDetail.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-components-path-items/output/com/sap/cloud/sdk/datamodel/rest/test/model/SodaDetail.java
new file mode 100644
index 0000000000..3e2fb390ff
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-components-path-items/output/com/sap/cloud/sdk/datamodel/rest/test/model/SodaDetail.java
@@ -0,0 +1,173 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+/*
+ * OAS 3.1 components/pathItems schema references
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonValue;
+import com.fasterxml.jackson.annotation.JsonAnySetter;
+import com.fasterxml.jackson.annotation.JsonAnyGetter;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * SodaDetail
+ */
+// CHECKSTYLE:OFF
+public class SodaDetail 
+// CHECKSTYLE:ON
+{
+  @JsonProperty("description")
+  private String description;
+
+  @JsonAnySetter
+  @JsonAnyGetter
+  private final Map<String, Object> cloudSdkCustomFields = new LinkedHashMap<>();
+
+  /**
+   * Set the description of this {@link SodaDetail} instance and return the same instance.
+   *
+   * @param description  The description of this {@link SodaDetail}
+   * @return The same instance of this {@link SodaDetail} class
+   */
+  @Nonnull public SodaDetail description( @Nullable final String description) {
+    this.description = description;
+    return this;
+  }
+
+  /**
+   * Get description
+   * @return description  The description of this {@link SodaDetail} instance.
+   */
+  @Nullable
+  public String getDescription() {
+    return description;
+  }
+
+  /**
+   * Set the description of this {@link SodaDetail} instance.
+   *
+   * @param description  The description of this {@link SodaDetail}
+   */
+  public void setDescription( @Nullable final String description) {
+    this.description = description;
+  }
+
+  /**
+   * Get the names of the unrecognizable properties of the {@link SodaDetail}.
+   * @return The set of properties names
+   */
+  @JsonIgnore
+  @Nonnull
+  public Set<String> getCustomFieldNames() {
+    return cloudSdkCustomFields.keySet();
+  }
+
+  /**
+   * Get the value of an unrecognizable property of this {@link SodaDetail} instance.
+   * @deprecated Use {@link #toMap()} instead.
+   * @param name  The name of the property
+   * @return The value of the property
+   * @throws NoSuchElementException  If no property with the given name could be found.
+   */
+  @Nullable
+  @Deprecated
+  public Object getCustomField( @Nonnull final String name ) throws NoSuchElementException {
+    if( !cloudSdkCustomFields.containsKey(name) ) {
+        throw new NoSuchElementException("SodaDetail has no field with name '" + name + "'.");
+    }
+    return cloudSdkCustomFields.get(name);
+  }
+
+  /**
+   * Get the value of all properties of this {@link SodaDetail} instance including unrecognized properties.
+   *
+   * @return The map of all properties
+   */
+  @JsonIgnore
+  @Nonnull
+  public Map<String, Object> toMap()
+  {
+    final Map<String, Object> declaredFields = new LinkedHashMap<>(cloudSdkCustomFields);
+    if( description != null ) declaredFields.put("description", description);
+    return declaredFields;
+  }
+
+  /**
+   * Set an unrecognizable property of this {@link SodaDetail} instance. If the map previously contained a mapping
+   * for the key, the old value is replaced by the specified value.
+   * @param customFieldName The name of the property
+   * @param customFieldValue The value of the property
+   */
+  @JsonIgnore
+  public void setCustomField( @Nonnull String customFieldName, @Nullable Object customFieldValue )
+  {
+      cloudSdkCustomFields.put(customFieldName, customFieldValue);
+  }
+
+
+  @Override
+  public boolean equals(@Nullable final java.lang.Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    final SodaDetail sodaDetail = (SodaDetail) o;
+    return Objects.equals(this.cloudSdkCustomFields, sodaDetail.cloudSdkCustomFields) &&
+        Objects.equals(this.description, sodaDetail.description);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(description, cloudSdkCustomFields);
+  }
+
+  @Override
+  @Nonnull public String toString() {
+    final StringBuilder sb = new StringBuilder();
+    sb.append("class SodaDetail {\n");
+    sb.append("    description: ").append(toIndentedString(description)).append("\n");
+    cloudSdkCustomFields.forEach((k,v) -> sb.append("    ").append(k).append(": ").append(toIndentedString(v)).append("\n"));
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(final java.lang.Object o) {
+    if (o == null) {
+      return "null";
+    }
+    return o.toString().replace("\n", "\n    ");
+  }
+
+}
+
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-exclusive-min-max/input/sodastore.yaml b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-exclusive-min-max/input/sodastore.yaml
new file mode 100644
index 0000000000..913834b7c5
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-exclusive-min-max/input/sodastore.yaml
@@ -0,0 +1,47 @@
+openapi: 3.1.0
+info:
+  title: OAS 3.1 Numeric exclusiveMinimum and exclusiveMaximum
+  version: 1.0.0
+
+paths:
+  /sodas:
+    get:
+      operationId: getSodas
+      responses:
+        '200':
+          description: A soda
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Soda'
+
+components:
+  schemas:
+    Soda:
+      type: object
+      properties:
+        name:
+          type: string
+        rating:
+          # numeric exclusiveMinimum/exclusiveMaximum as direct values
+          type: number
+          exclusiveMinimum: 0
+          exclusiveMaximum: 5
+        score:
+          # OAS 3.1: non-exclusive minimum/maximum (plain numeric values)
+          type: number
+          minimum: 0
+          maximum: 100
+        temperature:
+          # OAS 3.1: mixed — inclusive minimum alongside exclusive maximum
+          type: number
+          minimum: 0
+          exclusiveMaximum: 100
+        combo:
+          # OAS 3.1: both minimum (inclusive) and exclusiveMinimum (exclusive numeric) present;
+          # exclusiveMinimum: 3 is stricter than minimum: 2, so effective constraint is > 3
+          type: number
+          minimum: 2
+          exclusiveMinimum: 3
+      required:
+        - name
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
new file mode 100644
index 0000000000..176600d2e7
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.api;
+
+import com.sap.cloud.sdk.services.openapi.core.OpenApiRequestException;
+import com.sap.cloud.sdk.services.openapi.core.OpenApiResponse;
+import com.sap.cloud.sdk.services.openapi.core.AbstractOpenApiService;
+import com.sap.cloud.sdk.services.openapi.apiclient.ApiClient;
+
+import com.sap.cloud.sdk.datamodel.rest.test.model.Soda;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+
+import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.MultiValueMap;
+import org.springframework.web.util.UriComponentsBuilder;
+import org.springframework.core.ParameterizedTypeReference;
+import org.springframework.core.io.FileSystemResource;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.MediaType;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import com.google.common.annotations.Beta;
+
+import com.sap.cloud.sdk.cloudplatform.connectivity.Destination;
+
+/**
+ * OAS 3.1 Numeric exclusiveMinimum and exclusiveMaximum in version 1.0.0.
+ *
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ */
+public class DefaultApi extends AbstractOpenApiService {
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.1 Numeric exclusiveMinimum and exclusiveMaximum.
+     *
+     * @param httpDestination The destination that API should be used with
+     */
+    public DefaultApi( @Nonnull final Destination httpDestination )
+    {
+        super(httpDestination);
+    }
+
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.1 Numeric exclusiveMinimum and exclusiveMaximum based on a given {@link ApiClient}.
+     *
+     * @param apiClient
+     *            ApiClient to invoke the API on
+     */
+    @Beta
+    public DefaultApi( @Nonnull final ApiClient apiClient )
+    {
+         super(apiClient);
+    }
+
+        /**
+     * <p></p>
+     * <p></p>
+     * <p><b>200</b> - A soda
+     * @return Soda
+     * @throws OpenApiRequestException if an error occurs while attempting to invoke the API
+     */
+    @Nonnull
+    public Soda getSodas() throws OpenApiRequestException {
+        final Object localVarPostBody = null;
+        
+        final String localVarPath = UriComponentsBuilder.fromPath("/sodas").build().toUriString();
+
+        final MultiValueMap<String, String> localVarQueryParams = new LinkedMultiValueMap<String, String>();
+        final HttpHeaders localVarHeaderParams = new HttpHeaders();
+        final MultiValueMap<String, Object> localVarFormParams = new LinkedMultiValueMap<String, Object>();
+
+        final String[] localVarAccepts = { 
+            "application/json"
+        };
+        final List<MediaType> localVarAccept = apiClient.selectHeaderAccept(localVarAccepts);
+        final String[] localVarContentTypes = { };
+        final MediaType localVarContentType = apiClient.selectHeaderContentType(localVarContentTypes);
+
+        final String[] localVarAuthNames = new String[] {  };
+
+        final ParameterizedTypeReference<Soda> localVarReturnType = new ParameterizedTypeReference<Soda>() {};
+        return apiClient.invokeAPI(localVarPath, HttpMethod.GET, localVarQueryParams, localVarPostBody, localVarHeaderParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
+    }
+}
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
new file mode 100644
index 0000000000..4b6196d63c
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-exclusive-min-max/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
@@ -0,0 +1,335 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+/*
+ * OAS 3.1 Numeric exclusiveMinimum and exclusiveMaximum
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonValue;
+import java.math.BigDecimal;
+import com.fasterxml.jackson.annotation.JsonAnySetter;
+import com.fasterxml.jackson.annotation.JsonAnyGetter;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * Soda
+ */
+// CHECKSTYLE:OFF
+public class Soda 
+// CHECKSTYLE:ON
+{
+  @JsonProperty("name")
+  private String name;
+
+  @JsonProperty("rating")
+  private BigDecimal rating;
+
+  @JsonProperty("score")
+  private BigDecimal score;
+
+  @JsonProperty("temperature")
+  private BigDecimal temperature;
+
+  @JsonProperty("combo")
+  private BigDecimal combo;
+
+  @JsonAnySetter
+  @JsonAnyGetter
+  private final Map<String, Object> cloudSdkCustomFields = new LinkedHashMap<>();
+
+  /**
+   * Set the name of this {@link Soda} instance and return the same instance.
+   *
+   * @param name  The name of this {@link Soda}
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda name( @Nonnull final String name) {
+    this.name = name;
+    return this;
+  }
+
+  /**
+   * Get name
+   * @return name  The name of this {@link Soda} instance.
+   */
+  @Nonnull
+  public String getName() {
+    return name;
+  }
+
+  /**
+   * Set the name of this {@link Soda} instance.
+   *
+   * @param name  The name of this {@link Soda}
+   */
+  public void setName( @Nonnull final String name) {
+    this.name = name;
+  }
+
+  /**
+   * Set the rating of this {@link Soda} instance and return the same instance.
+   *
+   * @param rating  The rating of this {@link Soda}
+   * Minimum: 0 (exclusive)
+   * Maximum: 5 (exclusive)
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda rating( @Nullable final BigDecimal rating) {
+    this.rating = rating;
+    return this;
+  }
+
+  /**
+   * Get rating
+   * minimum: 0 (exclusive)
+   * maximum: 5 (exclusive)
+   * @return rating  The rating of this {@link Soda} instance.
+   */
+  @Nullable
+  public BigDecimal getRating() {
+    return rating;
+  }
+
+  /**
+   * Set the rating of this {@link Soda} instance.
+   *
+   * @param rating  The rating of this {@link Soda}
+   * Minimum: 0 (exclusive)
+   * Maximum: 5 (exclusive)
+   */
+  public void setRating( @Nullable final BigDecimal rating) {
+    this.rating = rating;
+  }
+
+  /**
+   * Set the score of this {@link Soda} instance and return the same instance.
+   *
+   * @param score  The score of this {@link Soda}
+   * Minimum: 0
+   * Maximum: 100
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda score( @Nullable final BigDecimal score) {
+    this.score = score;
+    return this;
+  }
+
+  /**
+   * Get score
+   * minimum: 0
+   * maximum: 100
+   * @return score  The score of this {@link Soda} instance.
+   */
+  @Nullable
+  public BigDecimal getScore() {
+    return score;
+  }
+
+  /**
+   * Set the score of this {@link Soda} instance.
+   *
+   * @param score  The score of this {@link Soda}
+   * Minimum: 0
+   * Maximum: 100
+   */
+  public void setScore( @Nullable final BigDecimal score) {
+    this.score = score;
+  }
+
+  /**
+   * Set the temperature of this {@link Soda} instance and return the same instance.
+   *
+   * @param temperature  The temperature of this {@link Soda}
+   * Minimum: 0
+   * Maximum: 100 (exclusive)
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda temperature( @Nullable final BigDecimal temperature) {
+    this.temperature = temperature;
+    return this;
+  }
+
+  /**
+   * Get temperature
+   * minimum: 0
+   * maximum: 100 (exclusive)
+   * @return temperature  The temperature of this {@link Soda} instance.
+   */
+  @Nullable
+  public BigDecimal getTemperature() {
+    return temperature;
+  }
+
+  /**
+   * Set the temperature of this {@link Soda} instance.
+   *
+   * @param temperature  The temperature of this {@link Soda}
+   * Minimum: 0
+   * Maximum: 100 (exclusive)
+   */
+  public void setTemperature( @Nullable final BigDecimal temperature) {
+    this.temperature = temperature;
+  }
+
+  /**
+   * Set the combo of this {@link Soda} instance and return the same instance.
+   *
+   * @param combo  The combo of this {@link Soda}
+   * Minimum: 3 (exclusive)
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda combo( @Nullable final BigDecimal combo) {
+    this.combo = combo;
+    return this;
+  }
+
+  /**
+   * Get combo
+   * minimum: 3 (exclusive)
+   * @return combo  The combo of this {@link Soda} instance.
+   */
+  @Nullable
+  public BigDecimal getCombo() {
+    return combo;
+  }
+
+  /**
+   * Set the combo of this {@link Soda} instance.
+   *
+   * @param combo  The combo of this {@link Soda}
+   * Minimum: 3 (exclusive)
+   */
+  public void setCombo( @Nullable final BigDecimal combo) {
+    this.combo = combo;
+  }
+
+  /**
+   * Get the names of the unrecognizable properties of the {@link Soda}.
+   * @return The set of properties names
+   */
+  @JsonIgnore
+  @Nonnull
+  public Set<String> getCustomFieldNames() {
+    return cloudSdkCustomFields.keySet();
+  }
+
+  /**
+   * Get the value of an unrecognizable property of this {@link Soda} instance.
+   * @deprecated Use {@link #toMap()} instead.
+   * @param name  The name of the property
+   * @return The value of the property
+   * @throws NoSuchElementException  If no property with the given name could be found.
+   */
+  @Nullable
+  @Deprecated
+  public Object getCustomField( @Nonnull final String name ) throws NoSuchElementException {
+    if( !cloudSdkCustomFields.containsKey(name) ) {
+        throw new NoSuchElementException("Soda has no field with name '" + name + "'.");
+    }
+    return cloudSdkCustomFields.get(name);
+  }
+
+  /**
+   * Get the value of all properties of this {@link Soda} instance including unrecognized properties.
+   *
+   * @return The map of all properties
+   */
+  @JsonIgnore
+  @Nonnull
+  public Map<String, Object> toMap()
+  {
+    final Map<String, Object> declaredFields = new LinkedHashMap<>(cloudSdkCustomFields);
+    if( name != null ) declaredFields.put("name", name);
+    if( rating != null ) declaredFields.put("rating", rating);
+    if( score != null ) declaredFields.put("score", score);
+    if( temperature != null ) declaredFields.put("temperature", temperature);
+    if( combo != null ) declaredFields.put("combo", combo);
+    return declaredFields;
+  }
+
+  /**
+   * Set an unrecognizable property of this {@link Soda} instance. If the map previously contained a mapping
+   * for the key, the old value is replaced by the specified value.
+   * @param customFieldName The name of the property
+   * @param customFieldValue The value of the property
+   */
+  @JsonIgnore
+  public void setCustomField( @Nonnull String customFieldName, @Nullable Object customFieldValue )
+  {
+      cloudSdkCustomFields.put(customFieldName, customFieldValue);
+  }
+
+
+  @Override
+  public boolean equals(@Nullable final java.lang.Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    final Soda soda = (Soda) o;
+    return Objects.equals(this.cloudSdkCustomFields, soda.cloudSdkCustomFields) &&
+        Objects.equals(this.name, soda.name) &&
+        Objects.equals(this.rating, soda.rating) &&
+        Objects.equals(this.score, soda.score) &&
+        Objects.equals(this.temperature, soda.temperature) &&
+        Objects.equals(this.combo, soda.combo);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(name, rating, score, temperature, combo, cloudSdkCustomFields);
+  }
+
+  @Override
+  @Nonnull public String toString() {
+    final StringBuilder sb = new StringBuilder();
+    sb.append("class Soda {\n");
+    sb.append("    name: ").append(toIndentedString(name)).append("\n");
+    sb.append("    rating: ").append(toIndentedString(rating)).append("\n");
+    sb.append("    score: ").append(toIndentedString(score)).append("\n");
+    sb.append("    temperature: ").append(toIndentedString(temperature)).append("\n");
+    sb.append("    combo: ").append(toIndentedString(combo)).append("\n");
+    cloudSdkCustomFields.forEach((k,v) -> sb.append("    ").append(k).append(": ").append(toIndentedString(v)).append("\n"));
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(final java.lang.Object o) {
+    if (o == null) {
+      return "null";
+    }
+    return o.toString().replace("\n", "\n    ");
+  }
+
+}
+
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-nullable-ref/input/sodastore.yaml b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-nullable-ref/input/sodastore.yaml
new file mode 100644
index 0000000000..19686b15ec
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-nullable-ref/input/sodastore.yaml
@@ -0,0 +1,37 @@
+openapi: 3.1.0
+info:
+  title: OAS 3.1 Nullable $ref via anyOf
+  version: 1.0.0
+
+paths:
+  /sodas:
+    get:
+      operationId: getSodas
+      responses:
+        '200':
+          description: A soda
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Soda'
+
+components:
+  schemas:
+    SodaCategory:
+      type: object
+      properties:
+        name:
+          type: string
+
+    Soda:
+      type: object
+      properties:
+        name:
+          type: string
+        category:
+          # nullable $ref using anyOf with null type
+          anyOf:
+            - $ref: '#/components/schemas/SodaCategory'
+            - type: "null"
+      required:
+        - name
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-nullable-ref/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-nullable-ref/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
new file mode 100644
index 0000000000..2eeec864d2
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-nullable-ref/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.api;
+
+import com.sap.cloud.sdk.services.openapi.core.OpenApiRequestException;
+import com.sap.cloud.sdk.services.openapi.core.OpenApiResponse;
+import com.sap.cloud.sdk.services.openapi.core.AbstractOpenApiService;
+import com.sap.cloud.sdk.services.openapi.apiclient.ApiClient;
+
+import com.sap.cloud.sdk.datamodel.rest.test.model.Soda;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+
+import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.MultiValueMap;
+import org.springframework.web.util.UriComponentsBuilder;
+import org.springframework.core.ParameterizedTypeReference;
+import org.springframework.core.io.FileSystemResource;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.MediaType;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import com.google.common.annotations.Beta;
+
+import com.sap.cloud.sdk.cloudplatform.connectivity.Destination;
+
+/**
+ * OAS 3.1 Nullable $ref via anyOf in version 1.0.0.
+ *
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ */
+public class DefaultApi extends AbstractOpenApiService {
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.1 Nullable $ref via anyOf.
+     *
+     * @param httpDestination The destination that API should be used with
+     */
+    public DefaultApi( @Nonnull final Destination httpDestination )
+    {
+        super(httpDestination);
+    }
+
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.1 Nullable $ref via anyOf based on a given {@link ApiClient}.
+     *
+     * @param apiClient
+     *            ApiClient to invoke the API on
+     */
+    @Beta
+    public DefaultApi( @Nonnull final ApiClient apiClient )
+    {
+         super(apiClient);
+    }
+
+        /**
+     * <p></p>
+     * <p></p>
+     * <p><b>200</b> - A soda
+     * @return Soda
+     * @throws OpenApiRequestException if an error occurs while attempting to invoke the API
+     */
+    @Nonnull
+    public Soda getSodas() throws OpenApiRequestException {
+        final Object localVarPostBody = null;
+        
+        final String localVarPath = UriComponentsBuilder.fromPath("/sodas").build().toUriString();
+
+        final MultiValueMap<String, String> localVarQueryParams = new LinkedMultiValueMap<String, String>();
+        final HttpHeaders localVarHeaderParams = new HttpHeaders();
+        final MultiValueMap<String, Object> localVarFormParams = new LinkedMultiValueMap<String, Object>();
+
+        final String[] localVarAccepts = { 
+            "application/json"
+        };
+        final List<MediaType> localVarAccept = apiClient.selectHeaderAccept(localVarAccepts);
+        final String[] localVarContentTypes = { };
+        final MediaType localVarContentType = apiClient.selectHeaderContentType(localVarContentTypes);
+
+        final String[] localVarAuthNames = new String[] {  };
+
+        final ParameterizedTypeReference<Soda> localVarReturnType = new ParameterizedTypeReference<Soda>() {};
+        return apiClient.invokeAPI(localVarPath, HttpMethod.GET, localVarQueryParams, localVarPostBody, localVarHeaderParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
+    }
+}
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-nullable-ref/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-nullable-ref/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
new file mode 100644
index 0000000000..7468af81f2
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-nullable-ref/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
@@ -0,0 +1,209 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+/*
+ * OAS 3.1 Nullable $ref via anyOf
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonValue;
+import com.sap.cloud.sdk.datamodel.rest.test.model.SodaCategory;
+import com.fasterxml.jackson.annotation.JsonAnySetter;
+import com.fasterxml.jackson.annotation.JsonAnyGetter;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * Soda
+ */
+// CHECKSTYLE:OFF
+public class Soda 
+// CHECKSTYLE:ON
+{
+  @JsonProperty("name")
+  private String name;
+
+  @JsonProperty("category")
+  private SodaCategory category;
+
+  @JsonAnySetter
+  @JsonAnyGetter
+  private final Map<String, Object> cloudSdkCustomFields = new LinkedHashMap<>();
+
+  /**
+   * Set the name of this {@link Soda} instance and return the same instance.
+   *
+   * @param name  The name of this {@link Soda}
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda name( @Nonnull final String name) {
+    this.name = name;
+    return this;
+  }
+
+  /**
+   * Get name
+   * @return name  The name of this {@link Soda} instance.
+   */
+  @Nonnull
+  public String getName() {
+    return name;
+  }
+
+  /**
+   * Set the name of this {@link Soda} instance.
+   *
+   * @param name  The name of this {@link Soda}
+   */
+  public void setName( @Nonnull final String name) {
+    this.name = name;
+  }
+
+  /**
+   * Set the category of this {@link Soda} instance and return the same instance.
+   *
+   * @param category  The category of this {@link Soda}
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda category( @Nullable final SodaCategory category) {
+    this.category = category;
+    return this;
+  }
+
+  /**
+   * Get category
+   * @return category  The category of this {@link Soda} instance.
+   */
+  @Nullable
+  public SodaCategory getCategory() {
+    return category;
+  }
+
+  /**
+   * Set the category of this {@link Soda} instance.
+   *
+   * @param category  The category of this {@link Soda}
+   */
+  public void setCategory( @Nullable final SodaCategory category) {
+    this.category = category;
+  }
+
+  /**
+   * Get the names of the unrecognizable properties of the {@link Soda}.
+   * @return The set of properties names
+   */
+  @JsonIgnore
+  @Nonnull
+  public Set<String> getCustomFieldNames() {
+    return cloudSdkCustomFields.keySet();
+  }
+
+  /**
+   * Get the value of an unrecognizable property of this {@link Soda} instance.
+   * @deprecated Use {@link #toMap()} instead.
+   * @param name  The name of the property
+   * @return The value of the property
+   * @throws NoSuchElementException  If no property with the given name could be found.
+   */
+  @Nullable
+  @Deprecated
+  public Object getCustomField( @Nonnull final String name ) throws NoSuchElementException {
+    if( !cloudSdkCustomFields.containsKey(name) ) {
+        throw new NoSuchElementException("Soda has no field with name '" + name + "'.");
+    }
+    return cloudSdkCustomFields.get(name);
+  }
+
+  /**
+   * Get the value of all properties of this {@link Soda} instance including unrecognized properties.
+   *
+   * @return The map of all properties
+   */
+  @JsonIgnore
+  @Nonnull
+  public Map<String, Object> toMap()
+  {
+    final Map<String, Object> declaredFields = new LinkedHashMap<>(cloudSdkCustomFields);
+    if( name != null ) declaredFields.put("name", name);
+    if( category != null ) declaredFields.put("category", category);
+    return declaredFields;
+  }
+
+  /**
+   * Set an unrecognizable property of this {@link Soda} instance. If the map previously contained a mapping
+   * for the key, the old value is replaced by the specified value.
+   * @param customFieldName The name of the property
+   * @param customFieldValue The value of the property
+   */
+  @JsonIgnore
+  public void setCustomField( @Nonnull String customFieldName, @Nullable Object customFieldValue )
+  {
+      cloudSdkCustomFields.put(customFieldName, customFieldValue);
+  }
+
+
+  @Override
+  public boolean equals(@Nullable final java.lang.Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    final Soda soda = (Soda) o;
+    return Objects.equals(this.cloudSdkCustomFields, soda.cloudSdkCustomFields) &&
+        Objects.equals(this.name, soda.name) &&
+        Objects.equals(this.category, soda.category);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(name, category, cloudSdkCustomFields);
+  }
+
+  @Override
+  @Nonnull public String toString() {
+    final StringBuilder sb = new StringBuilder();
+    sb.append("class Soda {\n");
+    sb.append("    name: ").append(toIndentedString(name)).append("\n");
+    sb.append("    category: ").append(toIndentedString(category)).append("\n");
+    cloudSdkCustomFields.forEach((k,v) -> sb.append("    ").append(k).append(": ").append(toIndentedString(v)).append("\n"));
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(final java.lang.Object o) {
+    if (o == null) {
+      return "null";
+    }
+    return o.toString().replace("\n", "\n    ");
+  }
+
+}
+
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-nullable-ref/output/com/sap/cloud/sdk/datamodel/rest/test/model/SodaCategory.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-nullable-ref/output/com/sap/cloud/sdk/datamodel/rest/test/model/SodaCategory.java
new file mode 100644
index 0000000000..632cf7a9d2
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-nullable-ref/output/com/sap/cloud/sdk/datamodel/rest/test/model/SodaCategory.java
@@ -0,0 +1,173 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+/*
+ * OAS 3.1 Nullable $ref via anyOf
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonValue;
+import com.fasterxml.jackson.annotation.JsonAnySetter;
+import com.fasterxml.jackson.annotation.JsonAnyGetter;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * SodaCategory
+ */
+// CHECKSTYLE:OFF
+public class SodaCategory 
+// CHECKSTYLE:ON
+{
+  @JsonProperty("name")
+  private String name;
+
+  @JsonAnySetter
+  @JsonAnyGetter
+  private final Map<String, Object> cloudSdkCustomFields = new LinkedHashMap<>();
+
+  /**
+   * Set the name of this {@link SodaCategory} instance and return the same instance.
+   *
+   * @param name  The name of this {@link SodaCategory}
+   * @return The same instance of this {@link SodaCategory} class
+   */
+  @Nonnull public SodaCategory name( @Nullable final String name) {
+    this.name = name;
+    return this;
+  }
+
+  /**
+   * Get name
+   * @return name  The name of this {@link SodaCategory} instance.
+   */
+  @Nullable
+  public String getName() {
+    return name;
+  }
+
+  /**
+   * Set the name of this {@link SodaCategory} instance.
+   *
+   * @param name  The name of this {@link SodaCategory}
+   */
+  public void setName( @Nullable final String name) {
+    this.name = name;
+  }
+
+  /**
+   * Get the names of the unrecognizable properties of the {@link SodaCategory}.
+   * @return The set of properties names
+   */
+  @JsonIgnore
+  @Nonnull
+  public Set<String> getCustomFieldNames() {
+    return cloudSdkCustomFields.keySet();
+  }
+
+  /**
+   * Get the value of an unrecognizable property of this {@link SodaCategory} instance.
+   * @deprecated Use {@link #toMap()} instead.
+   * @param name  The name of the property
+   * @return The value of the property
+   * @throws NoSuchElementException  If no property with the given name could be found.
+   */
+  @Nullable
+  @Deprecated
+  public Object getCustomField( @Nonnull final String name ) throws NoSuchElementException {
+    if( !cloudSdkCustomFields.containsKey(name) ) {
+        throw new NoSuchElementException("SodaCategory has no field with name '" + name + "'.");
+    }
+    return cloudSdkCustomFields.get(name);
+  }
+
+  /**
+   * Get the value of all properties of this {@link SodaCategory} instance including unrecognized properties.
+   *
+   * @return The map of all properties
+   */
+  @JsonIgnore
+  @Nonnull
+  public Map<String, Object> toMap()
+  {
+    final Map<String, Object> declaredFields = new LinkedHashMap<>(cloudSdkCustomFields);
+    if( name != null ) declaredFields.put("name", name);
+    return declaredFields;
+  }
+
+  /**
+   * Set an unrecognizable property of this {@link SodaCategory} instance. If the map previously contained a mapping
+   * for the key, the old value is replaced by the specified value.
+   * @param customFieldName The name of the property
+   * @param customFieldValue The value of the property
+   */
+  @JsonIgnore
+  public void setCustomField( @Nonnull String customFieldName, @Nullable Object customFieldValue )
+  {
+      cloudSdkCustomFields.put(customFieldName, customFieldValue);
+  }
+
+
+  @Override
+  public boolean equals(@Nullable final java.lang.Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    final SodaCategory sodaCategory = (SodaCategory) o;
+    return Objects.equals(this.cloudSdkCustomFields, sodaCategory.cloudSdkCustomFields) &&
+        Objects.equals(this.name, sodaCategory.name);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(name, cloudSdkCustomFields);
+  }
+
+  @Override
+  @Nonnull public String toString() {
+    final StringBuilder sb = new StringBuilder();
+    sb.append("class SodaCategory {\n");
+    sb.append("    name: ").append(toIndentedString(name)).append("\n");
+    cloudSdkCustomFields.forEach((k,v) -> sb.append("    ").append(k).append(": ").append(toIndentedString(v)).append("\n"));
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(final java.lang.Object o) {
+    if (o == null) {
+      return "null";
+    }
+    return o.toString().replace("\n", "\n    ");
+  }
+
+}
+
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-nullable-type-array/input/sodastore.yaml b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-nullable-type-array/input/sodastore.yaml
new file mode 100644
index 0000000000..c31da5b707
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-nullable-type-array/input/sodastore.yaml
@@ -0,0 +1,31 @@
+openapi: 3.1.0
+info:
+  title: OAS 3.1 Nullable Type Array
+  version: 1.0.0
+
+paths:
+  /sodas:
+    get:
+      operationId: getSodas
+      responses:
+        '200':
+          description: A soda
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Soda'
+
+components:
+  schemas:
+    Soda:
+      type: object
+      properties:
+        name:
+          type: string
+        brand:
+          # nullable via type array instead of nullable: true
+          type:
+            - string
+            - "null"
+      required:
+        - name
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-nullable-type-array/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-nullable-type-array/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
new file mode 100644
index 0000000000..fbfe5d2c65
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-nullable-type-array/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.api;
+
+import com.sap.cloud.sdk.services.openapi.core.OpenApiRequestException;
+import com.sap.cloud.sdk.services.openapi.core.OpenApiResponse;
+import com.sap.cloud.sdk.services.openapi.core.AbstractOpenApiService;
+import com.sap.cloud.sdk.services.openapi.apiclient.ApiClient;
+
+import com.sap.cloud.sdk.datamodel.rest.test.model.Soda;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+
+import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.MultiValueMap;
+import org.springframework.web.util.UriComponentsBuilder;
+import org.springframework.core.ParameterizedTypeReference;
+import org.springframework.core.io.FileSystemResource;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.MediaType;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import com.google.common.annotations.Beta;
+
+import com.sap.cloud.sdk.cloudplatform.connectivity.Destination;
+
+/**
+ * OAS 3.1 Nullable Type Array in version 1.0.0.
+ *
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ */
+public class DefaultApi extends AbstractOpenApiService {
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.1 Nullable Type Array.
+     *
+     * @param httpDestination The destination that API should be used with
+     */
+    public DefaultApi( @Nonnull final Destination httpDestination )
+    {
+        super(httpDestination);
+    }
+
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.1 Nullable Type Array based on a given {@link ApiClient}.
+     *
+     * @param apiClient
+     *            ApiClient to invoke the API on
+     */
+    @Beta
+    public DefaultApi( @Nonnull final ApiClient apiClient )
+    {
+         super(apiClient);
+    }
+
+        /**
+     * <p></p>
+     * <p></p>
+     * <p><b>200</b> - A soda
+     * @return Soda
+     * @throws OpenApiRequestException if an error occurs while attempting to invoke the API
+     */
+    @Nonnull
+    public Soda getSodas() throws OpenApiRequestException {
+        final Object localVarPostBody = null;
+        
+        final String localVarPath = UriComponentsBuilder.fromPath("/sodas").build().toUriString();
+
+        final MultiValueMap<String, String> localVarQueryParams = new LinkedMultiValueMap<String, String>();
+        final HttpHeaders localVarHeaderParams = new HttpHeaders();
+        final MultiValueMap<String, Object> localVarFormParams = new LinkedMultiValueMap<String, Object>();
+
+        final String[] localVarAccepts = { 
+            "application/json"
+        };
+        final List<MediaType> localVarAccept = apiClient.selectHeaderAccept(localVarAccepts);
+        final String[] localVarContentTypes = { };
+        final MediaType localVarContentType = apiClient.selectHeaderContentType(localVarContentTypes);
+
+        final String[] localVarAuthNames = new String[] {  };
+
+        final ParameterizedTypeReference<Soda> localVarReturnType = new ParameterizedTypeReference<Soda>() {};
+        return apiClient.invokeAPI(localVarPath, HttpMethod.GET, localVarQueryParams, localVarPostBody, localVarHeaderParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
+    }
+}
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-nullable-type-array/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-nullable-type-array/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
new file mode 100644
index 0000000000..5b36050103
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-nullable-type-array/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
@@ -0,0 +1,208 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+/*
+ * OAS 3.1 Nullable Type Array
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonValue;
+import com.fasterxml.jackson.annotation.JsonAnySetter;
+import com.fasterxml.jackson.annotation.JsonAnyGetter;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * Soda
+ */
+// CHECKSTYLE:OFF
+public class Soda 
+// CHECKSTYLE:ON
+{
+  @JsonProperty("name")
+  private String name;
+
+  @JsonProperty("brand")
+  private String brand;
+
+  @JsonAnySetter
+  @JsonAnyGetter
+  private final Map<String, Object> cloudSdkCustomFields = new LinkedHashMap<>();
+
+  /**
+   * Set the name of this {@link Soda} instance and return the same instance.
+   *
+   * @param name  The name of this {@link Soda}
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda name( @Nonnull final String name) {
+    this.name = name;
+    return this;
+  }
+
+  /**
+   * Get name
+   * @return name  The name of this {@link Soda} instance.
+   */
+  @Nonnull
+  public String getName() {
+    return name;
+  }
+
+  /**
+   * Set the name of this {@link Soda} instance.
+   *
+   * @param name  The name of this {@link Soda}
+   */
+  public void setName( @Nonnull final String name) {
+    this.name = name;
+  }
+
+  /**
+   * Set the brand of this {@link Soda} instance and return the same instance.
+   *
+   * @param brand  The brand of this {@link Soda}
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda brand( @Nullable final String brand) {
+    this.brand = brand;
+    return this;
+  }
+
+  /**
+   * Get brand
+   * @return brand  The brand of this {@link Soda} instance.
+   */
+  @Nullable
+  public String getBrand() {
+    return brand;
+  }
+
+  /**
+   * Set the brand of this {@link Soda} instance.
+   *
+   * @param brand  The brand of this {@link Soda}
+   */
+  public void setBrand( @Nullable final String brand) {
+    this.brand = brand;
+  }
+
+  /**
+   * Get the names of the unrecognizable properties of the {@link Soda}.
+   * @return The set of properties names
+   */
+  @JsonIgnore
+  @Nonnull
+  public Set<String> getCustomFieldNames() {
+    return cloudSdkCustomFields.keySet();
+  }
+
+  /**
+   * Get the value of an unrecognizable property of this {@link Soda} instance.
+   * @deprecated Use {@link #toMap()} instead.
+   * @param name  The name of the property
+   * @return The value of the property
+   * @throws NoSuchElementException  If no property with the given name could be found.
+   */
+  @Nullable
+  @Deprecated
+  public Object getCustomField( @Nonnull final String name ) throws NoSuchElementException {
+    if( !cloudSdkCustomFields.containsKey(name) ) {
+        throw new NoSuchElementException("Soda has no field with name '" + name + "'.");
+    }
+    return cloudSdkCustomFields.get(name);
+  }
+
+  /**
+   * Get the value of all properties of this {@link Soda} instance including unrecognized properties.
+   *
+   * @return The map of all properties
+   */
+  @JsonIgnore
+  @Nonnull
+  public Map<String, Object> toMap()
+  {
+    final Map<String, Object> declaredFields = new LinkedHashMap<>(cloudSdkCustomFields);
+    if( name != null ) declaredFields.put("name", name);
+    if( brand != null ) declaredFields.put("brand", brand);
+    return declaredFields;
+  }
+
+  /**
+   * Set an unrecognizable property of this {@link Soda} instance. If the map previously contained a mapping
+   * for the key, the old value is replaced by the specified value.
+   * @param customFieldName The name of the property
+   * @param customFieldValue The value of the property
+   */
+  @JsonIgnore
+  public void setCustomField( @Nonnull String customFieldName, @Nullable Object customFieldValue )
+  {
+      cloudSdkCustomFields.put(customFieldName, customFieldValue);
+  }
+
+
+  @Override
+  public boolean equals(@Nullable final java.lang.Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    final Soda soda = (Soda) o;
+    return Objects.equals(this.cloudSdkCustomFields, soda.cloudSdkCustomFields) &&
+        Objects.equals(this.name, soda.name) &&
+        Objects.equals(this.brand, soda.brand);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(name, brand, cloudSdkCustomFields);
+  }
+
+  @Override
+  @Nonnull public String toString() {
+    final StringBuilder sb = new StringBuilder();
+    sb.append("class Soda {\n");
+    sb.append("    name: ").append(toIndentedString(name)).append("\n");
+    sb.append("    brand: ").append(toIndentedString(brand)).append("\n");
+    cloudSdkCustomFields.forEach((k,v) -> sb.append("    ").append(k).append(": ").append(toIndentedString(v)).append("\n"));
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(final java.lang.Object o) {
+    if (o == null) {
+      return "null";
+    }
+    return o.toString().replace("\n", "\n    ");
+  }
+
+}
+
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-ref-with-sibling/input/sodastore.yaml b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-ref-with-sibling/input/sodastore.yaml
new file mode 100644
index 0000000000..081c006624
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-ref-with-sibling/input/sodastore.yaml
@@ -0,0 +1,34 @@
+openapi: 3.1.0
+info:
+  title: OAS 3.1 $ref with Sibling Properties
+  version: 1.0.0
+
+paths:
+  /sodas:
+    get:
+      operationId: getSodas
+      responses:
+        '200':
+          description: A soda
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Soda'
+
+components:
+  schemas:
+    SodaDescription:
+      type: string
+      description: Soda description
+
+    Soda:
+      type: object
+      properties:
+        name:
+          type: string
+        description:
+          # $ref with a sibling property — valid in OAS 3.1
+          $ref: '#/components/schemas/SodaDescription'
+          description: Soda description as part of the Soda object
+      required:
+        - name
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-ref-with-sibling/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-ref-with-sibling/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
new file mode 100644
index 0000000000..cb676c93a8
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-ref-with-sibling/output/com/sap/cloud/sdk/datamodel/rest/test/api/DefaultApi.java
@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.api;
+
+import com.sap.cloud.sdk.services.openapi.core.OpenApiRequestException;
+import com.sap.cloud.sdk.services.openapi.core.OpenApiResponse;
+import com.sap.cloud.sdk.services.openapi.core.AbstractOpenApiService;
+import com.sap.cloud.sdk.services.openapi.apiclient.ApiClient;
+
+import com.sap.cloud.sdk.datamodel.rest.test.model.Soda;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+
+import org.springframework.util.LinkedMultiValueMap;
+import org.springframework.util.MultiValueMap;
+import org.springframework.web.util.UriComponentsBuilder;
+import org.springframework.core.ParameterizedTypeReference;
+import org.springframework.core.io.FileSystemResource;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.MediaType;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import com.google.common.annotations.Beta;
+
+import com.sap.cloud.sdk.cloudplatform.connectivity.Destination;
+
+/**
+ * OAS 3.1 $ref with Sibling Properties in version 1.0.0.
+ *
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ */
+public class DefaultApi extends AbstractOpenApiService {
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.1 $ref with Sibling Properties.
+     *
+     * @param httpDestination The destination that API should be used with
+     */
+    public DefaultApi( @Nonnull final Destination httpDestination )
+    {
+        super(httpDestination);
+    }
+
+    /**
+     * Instantiates this API class to invoke operations on the OAS 3.1 $ref with Sibling Properties based on a given {@link ApiClient}.
+     *
+     * @param apiClient
+     *            ApiClient to invoke the API on
+     */
+    @Beta
+    public DefaultApi( @Nonnull final ApiClient apiClient )
+    {
+         super(apiClient);
+    }
+
+        /**
+     * <p></p>
+     * <p></p>
+     * <p><b>200</b> - A soda
+     * @return Soda
+     * @throws OpenApiRequestException if an error occurs while attempting to invoke the API
+     */
+    @Nonnull
+    public Soda getSodas() throws OpenApiRequestException {
+        final Object localVarPostBody = null;
+        
+        final String localVarPath = UriComponentsBuilder.fromPath("/sodas").build().toUriString();
+
+        final MultiValueMap<String, String> localVarQueryParams = new LinkedMultiValueMap<String, String>();
+        final HttpHeaders localVarHeaderParams = new HttpHeaders();
+        final MultiValueMap<String, Object> localVarFormParams = new LinkedMultiValueMap<String, Object>();
+
+        final String[] localVarAccepts = { 
+            "application/json"
+        };
+        final List<MediaType> localVarAccept = apiClient.selectHeaderAccept(localVarAccepts);
+        final String[] localVarContentTypes = { };
+        final MediaType localVarContentType = apiClient.selectHeaderContentType(localVarContentTypes);
+
+        final String[] localVarAuthNames = new String[] {  };
+
+        final ParameterizedTypeReference<Soda> localVarReturnType = new ParameterizedTypeReference<Soda>() {};
+        return apiClient.invokeAPI(localVarPath, HttpMethod.GET, localVarQueryParams, localVarPostBody, localVarHeaderParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
+    }
+}
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-ref-with-sibling/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-ref-with-sibling/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
new file mode 100644
index 0000000000..439c9072a5
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oas31-ref-with-sibling/output/com/sap/cloud/sdk/datamodel/rest/test/model/Soda.java
@@ -0,0 +1,208 @@
+/*
+ * Copyright (c) 2026 SAP SE or an SAP affiliate company. All rights reserved.
+ */
+
+/*
+ * OAS 3.1 $ref with Sibling Properties
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package com.sap.cloud.sdk.datamodel.rest.test.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.NoSuchElementException;
+import java.util.Set;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonValue;
+import com.fasterxml.jackson.annotation.JsonAnySetter;
+import com.fasterxml.jackson.annotation.JsonAnyGetter;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+/**
+ * Soda
+ */
+// CHECKSTYLE:OFF
+public class Soda 
+// CHECKSTYLE:ON
+{
+  @JsonProperty("name")
+  private String name;
+
+  @JsonProperty("description")
+  private String description;
+
+  @JsonAnySetter
+  @JsonAnyGetter
+  private final Map<String, Object> cloudSdkCustomFields = new LinkedHashMap<>();
+
+  /**
+   * Set the name of this {@link Soda} instance and return the same instance.
+   *
+   * @param name  The name of this {@link Soda}
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda name( @Nonnull final String name) {
+    this.name = name;
+    return this;
+  }
+
+  /**
+   * Get name
+   * @return name  The name of this {@link Soda} instance.
+   */
+  @Nonnull
+  public String getName() {
+    return name;
+  }
+
+  /**
+   * Set the name of this {@link Soda} instance.
+   *
+   * @param name  The name of this {@link Soda}
+   */
+  public void setName( @Nonnull final String name) {
+    this.name = name;
+  }
+
+  /**
+   * Set the description of this {@link Soda} instance and return the same instance.
+   *
+   * @param description  Soda description as part of the Soda object
+   * @return The same instance of this {@link Soda} class
+   */
+  @Nonnull public Soda description( @Nullable final String description) {
+    this.description = description;
+    return this;
+  }
+
+  /**
+   * Soda description as part of the Soda object
+   * @return description  The description of this {@link Soda} instance.
+   */
+  @Nullable
+  public String getDescription() {
+    return description;
+  }
+
+  /**
+   * Set the description of this {@link Soda} instance.
+   *
+   * @param description  Soda description as part of the Soda object
+   */
+  public void setDescription( @Nullable final String description) {
+    this.description = description;
+  }
+
+  /**
+   * Get the names of the unrecognizable properties of the {@link Soda}.
+   * @return The set of properties names
+   */
+  @JsonIgnore
+  @Nonnull
+  public Set<String> getCustomFieldNames() {
+    return cloudSdkCustomFields.keySet();
+  }
+
+  /**
+   * Get the value of an unrecognizable property of this {@link Soda} instance.
+   * @deprecated Use {@link #toMap()} instead.
+   * @param name  The name of the property
+   * @return The value of the property
+   * @throws NoSuchElementException  If no property with the given name could be found.
+   */
+  @Nullable
+  @Deprecated
+  public Object getCustomField( @Nonnull final String name ) throws NoSuchElementException {
+    if( !cloudSdkCustomFields.containsKey(name) ) {
+        throw new NoSuchElementException("Soda has no field with name '" + name + "'.");
+    }
+    return cloudSdkCustomFields.get(name);
+  }
+
+  /**
+   * Get the value of all properties of this {@link Soda} instance including unrecognized properties.
+   *
+   * @return The map of all properties
+   */
+  @JsonIgnore
+  @Nonnull
+  public Map<String, Object> toMap()
+  {
+    final Map<String, Object> declaredFields = new LinkedHashMap<>(cloudSdkCustomFields);
+    if( name != null ) declaredFields.put("name", name);
+    if( description != null ) declaredFields.put("description", description);
+    return declaredFields;
+  }
+
+  /**
+   * Set an unrecognizable property of this {@link Soda} instance. If the map previously contained a mapping
+   * for the key, the old value is replaced by the specified value.
+   * @param customFieldName The name of the property
+   * @param customFieldValue The value of the property
+   */
+  @JsonIgnore
+  public void setCustomField( @Nonnull String customFieldName, @Nullable Object customFieldValue )
+  {
+      cloudSdkCustomFields.put(customFieldName, customFieldValue);
+  }
+
+
+  @Override
+  public boolean equals(@Nullable final java.lang.Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    final Soda soda = (Soda) o;
+    return Objects.equals(this.cloudSdkCustomFields, soda.cloudSdkCustomFields) &&
+        Objects.equals(this.name, soda.name) &&
+        Objects.equals(this.description, soda.description);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(name, description, cloudSdkCustomFields);
+  }
+
+  @Override
+  @Nonnull public String toString() {
+    final StringBuilder sb = new StringBuilder();
+    sb.append("class Soda {\n");
+    sb.append("    name: ").append(toIndentedString(name)).append("\n");
+    sb.append("    description: ").append(toIndentedString(description)).append("\n");
+    cloudSdkCustomFields.forEach((k,v) -> sb.append("    ").append(k).append(": ").append(toIndentedString(v)).append("\n"));
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(final java.lang.Object o) {
+    if (o == null) {
+      return "null";
+    }
+    return o.toString().replace("\n", "\n    ");
+  }
+
+}
+
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/AllOf.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/AllOf.java
index 9dfaf3ea30..acb1c546e2 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/AllOf.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/AllOf.java
@@ -63,7 +63,7 @@ public class AllOf
    * Get sodaType
    * @return sodaType  The sodaType of this {@link AllOf} instance.
    */
-  @Nonnull
+  @Nullable
   public String getSodaType() {
     return sodaType;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/AnyOf.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/AnyOf.java
index 59f1e77c07..caa2a6634d 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/AnyOf.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/AnyOf.java
@@ -65,7 +65,7 @@ public class AnyOf
    * Get sodaType
    * @return sodaType  The sodaType of this {@link AnyOf} instance.
    */
-  @Nonnull
+  @Nullable
   public String getSodaType() {
     return sodaType;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/Cola.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/Cola.java
index 523e3146a8..9bb0649a9e 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/Cola.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/Cola.java
@@ -63,7 +63,7 @@ public class Cola
    * Get sodaType
    * @return sodaType  The sodaType of this {@link Cola} instance.
    */
-  @Nonnull
+  @Nullable
   public String getSodaType() {
     return sodaType;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/Fanta.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/Fanta.java
index 349aeaae22..d017ff606b 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/Fanta.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/Fanta.java
@@ -63,7 +63,7 @@ public class Fanta
    * Get sodaType
    * @return sodaType  The sodaType of this {@link Fanta} instance.
    */
-  @Nonnull
+  @Nullable
   public String getSodaType() {
     return sodaType;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/OneOf.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/OneOf.java
index e41a7b7929..2d7585849f 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/OneOf.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/OneOf.java
@@ -65,7 +65,7 @@ public class OneOf
    * Get sodaType
    * @return sodaType  The sodaType of this {@link OneOf} instance.
    */
-  @Nonnull
+  @Nullable
   public String getSodaType() {
     return sodaType;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/OneOfWithDiscriminator.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/OneOfWithDiscriminator.java
index 5e2f1fc1cb..38866718d0 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/OneOfWithDiscriminator.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/OneOfWithDiscriminator.java
@@ -73,7 +73,7 @@ public class OneOfWithDiscriminator
    * Get sodaType
    * @return sodaType  The sodaType of this {@link OneOfWithDiscriminator} instance.
    */
-  @Nonnull
+  @Nullable
   public String getSodaType() {
     return sodaType;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/OneOfWithDiscriminatorAndMapping.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/OneOfWithDiscriminatorAndMapping.java
index 0fab43fec8..0003a28685 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/OneOfWithDiscriminatorAndMapping.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-disabled/output/test/OneOfWithDiscriminatorAndMapping.java
@@ -73,7 +73,7 @@ public class OneOfWithDiscriminatorAndMapping
    * Get sodaType
    * @return sodaType  The sodaType of this {@link OneOfWithDiscriminatorAndMapping} instance.
    */
-  @Nonnull
+  @Nullable
   public String getSodaType() {
     return sodaType;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-enabled/output/test/AllOf.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-enabled/output/test/AllOf.java
index 67c23e5780..b98dc1c9f8 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-enabled/output/test/AllOf.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-enabled/output/test/AllOf.java
@@ -72,7 +72,7 @@ public class AllOf
    * Get sodaType
    * @return sodaType  The sodaType of this {@link AllOf} instance.
    */
-  @Nonnull
+  @Nullable
   public String getSodaType() {
     return sodaType;
   }
@@ -101,7 +101,7 @@ public void setSodaType( @Nullable final String sodaType) {
    * Get barCode
    * @return barCode  The barCode of this {@link AllOf} instance.
    */
-  @Nonnull
+  @Nullable
   public ColaBarCode getBarCode() {
     return barCode;
   }
@@ -130,7 +130,7 @@ public void setBarCode( @Nullable final ColaBarCode barCode) {
    * Get flavor
    * @return flavor  The flavor of this {@link AllOf} instance.
    */
-  @Nonnull
+  @Nullable
   public FantaFlavor getFlavor() {
     return flavor;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-enabled/output/test/AnyOf.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-enabled/output/test/AnyOf.java
index 367a2551d9..f168f1fe8a 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-enabled/output/test/AnyOf.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-enabled/output/test/AnyOf.java
@@ -74,7 +74,7 @@ public class AnyOf
    * Get sodaType
    * @return sodaType  The sodaType of this {@link AnyOf} instance.
    */
-  @Nonnull
+  @Nullable
   public String getSodaType() {
     return sodaType;
   }
@@ -103,7 +103,7 @@ public void setSodaType( @Nullable final String sodaType) {
    * Get barCode
    * @return barCode  The barCode of this {@link AnyOf} instance.
    */
-  @Nonnull
+  @Nullable
   public ColaBarCode getBarCode() {
     return barCode;
   }
@@ -132,7 +132,7 @@ public void setBarCode( @Nullable final ColaBarCode barCode) {
    * Get flavor
    * @return flavor  The flavor of this {@link AnyOf} instance.
    */
-  @Nonnull
+  @Nullable
   public FantaFlavor getFlavor() {
     return flavor;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-enabled/output/test/Cola.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-enabled/output/test/Cola.java
index 5a8354f0cc..b0597db43b 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-enabled/output/test/Cola.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-enabled/output/test/Cola.java
@@ -71,7 +71,7 @@ public class Cola implements OneOf, OneOfWithDiscriminator, OneOfWithDiscriminat
    * Get sodaType
    * @return sodaType  The sodaType of this {@link Cola} instance.
    */
-  @Nonnull
+  @Nullable
   public String getSodaType() {
     return sodaType;
   }
@@ -100,7 +100,7 @@ public void setSodaType( @Nullable final String sodaType) {
    * Get barCode
    * @return barCode  The barCode of this {@link Cola} instance.
    */
-  @Nonnull
+  @Nullable
   public ColaBarCode getBarCode() {
     return barCode;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-enabled/output/test/Fanta.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-enabled/output/test/Fanta.java
index 877eb424e4..5ef1720d8a 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-enabled/output/test/Fanta.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/oneof-interfaces-enabled/output/test/Fanta.java
@@ -71,7 +71,7 @@ public class Fanta implements OneOf, OneOfWithDiscriminator, OneOfWithDiscrimina
    * Get sodaType
    * @return sodaType  The sodaType of this {@link Fanta} instance.
    */
-  @Nonnull
+  @Nullable
   public String getSodaType() {
     return sodaType;
   }
@@ -100,7 +100,7 @@ public void setSodaType( @Nullable final String sodaType) {
    * Get flavor
    * @return flavor  The flavor of this {@link Fanta} instance.
    */
-  @Nonnull
+  @Nullable
   public FantaFlavor getFlavor() {
     return flavor;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/partial-generation/output/com/sap/cloud/sdk/services/builder/model/Soda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/partial-generation/output/com/sap/cloud/sdk/services/builder/model/Soda.java
index 45a204a0fc..8e84b6fe21 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/partial-generation/output/com/sap/cloud/sdk/services/builder/model/Soda.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/partial-generation/output/com/sap/cloud/sdk/services/builder/model/Soda.java
@@ -75,7 +75,7 @@ public class Soda
    * Get id
    * @return id  The id of this {@link Soda} instance.
    */
-  @Nonnull
+  @Nullable
   public Long getId() {
     return id;
   }
@@ -162,7 +162,7 @@ public void setBrand( @Nonnull final String brand) {
    * Get isAvailable
    * @return isAvailable  The isAvailable of this {@link Soda} instance.
    */
-  @Nonnull
+  @Nullable
   public Boolean isIsAvailable() {
     return isAvailable;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/partial-generation/output/com/sap/cloud/sdk/services/builder/model/SodaWithFoo.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/partial-generation/output/com/sap/cloud/sdk/services/builder/model/SodaWithFoo.java
index edccab010d..22a7aeff5b 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/partial-generation/output/com/sap/cloud/sdk/services/builder/model/SodaWithFoo.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/partial-generation/output/com/sap/cloud/sdk/services/builder/model/SodaWithFoo.java
@@ -75,7 +75,7 @@ public class SodaWithFoo
    * Get id
    * @return id  The id of this {@link SodaWithFoo} instance.
    */
-  @Nonnull
+  @Nullable
   public Long getId() {
     return id;
   }
@@ -162,7 +162,7 @@ public void setBrand( @Nonnull final String brand) {
    * Get isAvailable
    * @return isAvailable  The isAvailable of this {@link SodaWithFoo} instance.
    */
-  @Nonnull
+  @Nullable
   public Boolean isIsAvailable() {
     return isAvailable;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/partial-generation/output/com/sap/cloud/sdk/services/builder/model/UpdateSoda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/partial-generation/output/com/sap/cloud/sdk/services/builder/model/UpdateSoda.java
index 40d04555dd..564bcc1d79 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/partial-generation/output/com/sap/cloud/sdk/services/builder/model/UpdateSoda.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/partial-generation/output/com/sap/cloud/sdk/services/builder/model/UpdateSoda.java
@@ -76,7 +76,7 @@ public class UpdateSoda
    * Get name
    * @return name  The name of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public String getName() {
     return name;
   }
@@ -105,7 +105,7 @@ public void setName( @Nullable final String name) {
    * Get zero
    * @return zero  The zero of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public Boolean isZero() {
     return zero;
   }
@@ -134,7 +134,7 @@ public void setZero( @Nullable final Boolean zero) {
    * Get since
    * @return since  The since of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public LocalDate getSince() {
     return since;
   }
@@ -163,7 +163,7 @@ public void setSince( @Nullable final LocalDate since) {
    * Get brand
    * @return brand  The brand of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public String getBrand() {
     return brand;
   }
@@ -192,7 +192,7 @@ public void setBrand( @Nullable final String brand) {
    * Get price
    * @return price  The price of this {@link UpdateSoda} instance.
    */
-  @Nonnull
+  @Nullable
   public Float getPrice() {
     return price;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/remove-operation-id-prefix/output/com/sap/cloud/sdk/services/builder/model/Order.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/remove-operation-id-prefix/output/com/sap/cloud/sdk/services/builder/model/Order.java
index 30c807a7b3..44788e1d0f 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/remove-operation-id-prefix/output/com/sap/cloud/sdk/services/builder/model/Order.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/remove-operation-id-prefix/output/com/sap/cloud/sdk/services/builder/model/Order.java
@@ -133,7 +133,7 @@ public void setQuantity( @Nonnull final Integer quantity) {
    * Get totalPrice
    * @return totalPrice  The totalPrice of this {@link Order} instance.
    */
-  @Nonnull
+  @Nullable
   public Float getTotalPrice() {
     return totalPrice;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/remove-operation-id-prefix/output/com/sap/cloud/sdk/services/builder/model/OrderWithTimestamp.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/remove-operation-id-prefix/output/com/sap/cloud/sdk/services/builder/model/OrderWithTimestamp.java
index b81a924cb9..0ebaa8792f 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/remove-operation-id-prefix/output/com/sap/cloud/sdk/services/builder/model/OrderWithTimestamp.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/remove-operation-id-prefix/output/com/sap/cloud/sdk/services/builder/model/OrderWithTimestamp.java
@@ -137,7 +137,7 @@ public void setQuantity( @Nonnull final Integer quantity) {
    * Get totalPrice
    * @return totalPrice  The totalPrice of this {@link OrderWithTimestamp} instance.
    */
-  @Nonnull
+  @Nullable
   public Float getTotalPrice() {
     return totalPrice;
   }
@@ -224,7 +224,7 @@ public void setNullableProperty( @Nullable final String nullableProperty) {
    * Get timestamp
    * @return timestamp  The timestamp of this {@link OrderWithTimestamp} instance.
    */
-  @Nonnull
+  @Nullable
   public OffsetDateTime getTimestamp() {
     return timestamp;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/remove-operation-id-prefix/output/com/sap/cloud/sdk/services/builder/model/Soda.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/remove-operation-id-prefix/output/com/sap/cloud/sdk/services/builder/model/Soda.java
index 862a33733d..fecd099eaa 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/remove-operation-id-prefix/output/com/sap/cloud/sdk/services/builder/model/Soda.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/remove-operation-id-prefix/output/com/sap/cloud/sdk/services/builder/model/Soda.java
@@ -221,7 +221,7 @@ public void setQuantity( @Nonnull final Integer quantity) {
    * Get packaging
    * @return packaging  The packaging of this {@link Soda} instance.
    */
-  @Nonnull
+  @Nullable
   public PackagingEnum getPackaging() {
     return packaging;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/remove-operation-id-prefix/output/com/sap/cloud/sdk/services/builder/model/SodaWithId.java b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/remove-operation-id-prefix/output/com/sap/cloud/sdk/services/builder/model/SodaWithId.java
index 70553d4ca3..e04f94e4c6 100644
--- a/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/remove-operation-id-prefix/output/com/sap/cloud/sdk/services/builder/model/SodaWithId.java
+++ b/datamodel/openapi/openapi-generator/src/test/resources/DataModelGeneratorIntegrationTest/remove-operation-id-prefix/output/com/sap/cloud/sdk/services/builder/model/SodaWithId.java
@@ -224,7 +224,7 @@ public void setQuantity( @Nonnull final Integer quantity) {
    * Get packaging
    * @return packaging  The packaging of this {@link SodaWithId} instance.
    */
-  @Nonnull
+  @Nullable
   public PackagingEnum getPackaging() {
     return packaging;
   }
@@ -282,7 +282,7 @@ public void setPrice( @Nonnull final Float price) {
    * Get id
    * @return id  The id of this {@link SodaWithId} instance.
    */
-  @Nonnull
+  @Nullable
   public Long getId() {
     return id;
   }
diff --git a/datamodel/openapi/openapi-generator/src/test/resources/ValidationKeywordsPreprocessorTest/sodastore-31-nullable.json b/datamodel/openapi/openapi-generator/src/test/resources/ValidationKeywordsPreprocessorTest/sodastore-31-nullable.json
new file mode 100644
index 0000000000..cdb6054207
--- /dev/null
+++ b/datamodel/openapi/openapi-generator/src/test/resources/ValidationKeywordsPreprocessorTest/sodastore-31-nullable.json
@@ -0,0 +1,67 @@
+{
+  "openapi": "3.1.0",
+  "info": {
+    "title": "OAS 3.1 Nullable Test API",
+    "version": "1.0.0"
+  },
+  "paths": {
+    "/sodas": {
+      "post": {
+        "operationId": "addSoda",
+        "summary": "Add a soda with nullable fields",
+        "requestBody": {
+          "required": true,
+          "content": {
+            "application/json": {
+              "schema": {
+                "type": "object",
+                "properties": {
+                  "name": {
+                    "type": "string"
+                  },
+                  "brand": {
+                    "anyOf": [
+                      { "$ref": "#/components/schemas/Brand" },
+                      { "type": "null" }
+                    ]
+                  }
+                }
+              }
+            }
+          }
+        },
+        "responses": {
+          "201": {
+            "description": "Created"
+          }
+        }
+      }
+    }
+  },
+  "components": {
+    "schemas": {
+      "Brand": {
+        "type": "object",
+        "properties": {
+          "name": {
+            "type": "string"
+          }
+        }
+      },
+      "NullableRef": {
+        "type": "object",
+        "properties": {
+          "optionalBrand": {
+            "anyOf": [
+              { "$ref": "#/components/schemas/Brand" },
+              { "type": "null" }
+            ]
+          },
+          "requiredName": {
+            "type": "string"
+          }
+        }
+      }
+    }
+  }
+}