diff --git a/core/src/main/java/io/apitomy/hub/api/codegen/OpenApi2JaxRs.java b/core/src/main/java/io/apitomy/hub/api/codegen/OpenApi2JaxRs.java
index d45d31f5..9e2c1684 100755
--- a/core/src/main/java/io/apitomy/hub/api/codegen/OpenApi2JaxRs.java
+++ b/core/src/main/java/io/apitomy/hub/api/codegen/OpenApi2JaxRs.java
@@ -33,9 +33,9 @@
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.Date;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.Optional;
 import java.util.Properties;
 import java.util.Set;
@@ -109,7 +109,7 @@
  */
 public class OpenApi2JaxRs {
 
-    static final Map<String, Type<?>> TYPE_CACHE = new HashMap<>();
+    static final Map<String, Type<?>> TYPE_CACHE = new ConcurrentHashMap<>();
     static final String OPENAPI_OPERATION_ANNOTATION = "org.eclipse.microprofile.openapi.annotations.Operation";
     private static final String MEDIA_TYPE_CONSTANT_PREFIX = "MediaType.";
 
diff --git a/maven-plugin/src/main/java/io/apitomy/codegen/maven/GenerateCodeMojo.java b/maven-plugin/src/main/java/io/apitomy/codegen/maven/GenerateCodeMojo.java
index e3f80f31..2d07ea7d 100755
--- a/maven-plugin/src/main/java/io/apitomy/codegen/maven/GenerateCodeMojo.java
+++ b/maven-plugin/src/main/java/io/apitomy/codegen/maven/GenerateCodeMojo.java
@@ -25,7 +25,7 @@
  * 
  * @author eric.wittmann@gmail.com
  */
-@Mojo(name = "generate")
+@Mojo(name = "generate", threadSafe = true)
 public class GenerateCodeMojo extends AbstractMojo {
 
     /**