iGaming Java Evolution

A didactic, vanilla Java project (no frameworks) that showcases, in a practical way, the major evolutions of the language from Java 8 to Java 26.

Instead of toy snippets, the features are put to work inside a realistic — but deliberately bounded — iGaming / sports-betting domain: odds, stakes, betting tickets and the calculation of potential winnings.

Why this exists: most "what's new in Java X" resources are isolated one-liners. This repo is the opposite: one coherent domain, built with modern Java only, where every major language feature is used where it naturally fits and is marked with a comment explaining which version introduced it and what benefit it brings.

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Design principles

• Modern Java only. No legacy / before-after code. The idiomatic modern form is the only form shown. Each major feature carries a didactic comment.
• Vanilla. No Spring, no framework. Logging via the JDK's System.Logger (zero dependencies). Third-party libraries are allowed only when they add real value.
• Correct by domain. Money is modeled with BigDecimal, not double, to avoid floating-point rounding errors — as any real financial system must.
• Verifiable. Every type is covered by JUnit 5 tests; each module will also expose a runnable main demo.

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Java features showcased

Features are introduced progressively, as the domain needs them.

Feature	Version	Where it is used
var (local type inference)	Java 10	local variables in calculations, tests and demos
Text blocks	Java 15	multi-line ticket "receipt" in the demo (planned)
Records	Java 16	Odds, Stake, Selection, and the bet types
Pattern matching for instanceof	Java 16	targeted validations (planned)
Sealed interfaces	Java 17	Bet and TicketStatus closed hierarchies (planned)
Pattern matching for switch	Java 21	winnings calculation by bet type (planned)
Record patterns (deconstruction)	Java 21	destructuring records inside the switch (planned)

Minor, isolated API tweaks are deliberately omitted — the focus is the major language evolutions.

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Requirements

• JDK 26 (the Gradle toolchain will provision/validate it).
• No global Gradle install needed — use the bundled wrapper (./gradlew).

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Getting started

# Run the tests
./gradlew test

# Run the application entry point
./gradlew run

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Project structure

Single Gradle module, one package per domain area.

src/
├── main/java/com/adrianodiaz/igamingjavaevolution/
│   ├── IgamingJavaEvolutionApplication.java   # entry point
│   ├── shared/
│   │   └── Messages.java                       # centralized string constants
│   └── betengine/                              # first domain module
│       ├── Odds.java                           # record + validation (BigDecimal)
│       └── Stake.java                          # record + validation (BigDecimal)
└── test/java/com/adrianodiaz/igamingjavaevolution/
    └── betengine/
        ├── OddsTest.java
        └── StakeTest.java

docs/
└── design/
    └── 2026-07-23-bet-engine-design.md         # full design of the bet-engine module

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Roadmap

The project grows module by module. The first module, bet-engine, is where the core value types and the winnings logic live.

bet-engine — in progress

• Odds — decimal odds value object (record, compact-constructor validation)
• Stake — wagered amount value object (record, BigDecimal)
• Selection — a pick composing Odds
• Bet — sealed interface: SingleBet, AccumulatorBet, SystemBet
• TicketStatus — sealed interface: Placed, Settled, Cancelled
• BettingTicket — aggregate record
• WinningsCalculator — switch pattern matching + record patterns
• BetEngineDemo — runnable main with a text-block receipt

Planned next

• Web playground (JDK com.sun.net.httpserver.HttpServer + plain HTML/JS, no framework) to exercise the engine from a browser.
• Further domain modules exploring more language features.

See docs/design/2026-07-23-bet-engine-design.md for the detailed design and step-by-step build guide.

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License

Educational project — free to read, learn from, and adapt.