[java] Fix java version defaulting

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java

@@ -1040,19 +1040,19 @@ public void preprocessOpenAPI(OpenAPI openAPI) {
             }
         }
 
+        // TODO: Setting additionalProperties is not the responsibility of this method. These side-effects should be moved elsewhere to prevent unexpected behaviors.
         if(artifactVersion == null) {
             // If no artifactVersion is provided in additional properties, version from API specification is used.
             // If none of them is provided then fallbacks to default version
-            if (additionalProperties.containsKey(CodegenConstants.ARTIFACT_VERSION)) {
+            if (additionalProperties.containsKey(CodegenConstants.ARTIFACT_VERSION) && additionalProperties.get(CodegenConstants.ARTIFACT_VERSION) != null) {
                 this.setArtifactVersion((String) additionalProperties.get(CodegenConstants.ARTIFACT_VERSION));
             } else if (openAPI.getInfo() != null && openAPI.getInfo().getVersion() != null) {
                 this.setArtifactVersion(openAPI.getInfo().getVersion());
             } else {
                 this.setArtifactVersion(ARTIFACT_VERSION_DEFAULT_VALUE);
             }
-        } else {
-            additionalProperties.put(CodegenConstants.ARTIFACT_VERSION, artifactVersion);
         }
+        additionalProperties.put(CodegenConstants.ARTIFACT_VERSION, artifactVersion);
 
         if (additionalProperties.containsKey(CodegenConstants.SNAPSHOT_VERSION)) {
             if (convertPropertyToBooleanAndWriteBack(CodegenConstants.SNAPSHOT_VERSION)) {

modules/openapi-generator/src/test/java/org/openapitools/codegen/java/AbstractJavaCodegenTest.java

@@ -303,6 +303,7 @@ public void additionalPropertyArtifactSnapShotVersionTest() {
     @Test(description = "tests if default version is used when neither OpenAPI version nor artifactVersion additional property has been provided")
     public void defaultVersionTest() {
         final P_AbstractJavaCodegen codegen = new P_AbstractJavaCodegen();
+        codegen.setArtifactVersion(null);
 
         OpenAPI api = TestUtils.createOpenAPI();
         api.getInfo().setVersion(null);
@@ -340,6 +341,55 @@ public void snapshotVersionOpenAPITest() {
         Assert.assertEquals(codegen.getArtifactVersion(), "2.0-SNAPSHOT");
     }
 
+    @Test(description = "tests if setting an artifact version programmatically persists to additional properties, when openapi version is null")
+    public void allowsProgrammaticallySettingArtifactVersionWithNullOpenApiVersion() {
+        final P_AbstractJavaCodegen codegen = new P_AbstractJavaCodegen();
+        final String version = "9.8.7-rc1";
+        codegen.setArtifactVersion(version);
+
+        OpenAPI api = TestUtils.createOpenAPI();
+        api.getInfo().setVersion(null);
+        codegen.processOpts();
+        codegen.preprocessOpenAPI(api);
+
+        Assert.assertEquals(codegen.getArtifactVersion(), version);
+        Assert.assertEquals(codegen.additionalProperties().get(CodegenConstants.ARTIFACT_VERSION), version);
+    }
+
+    @Test(description = "tests if setting an artifact version programmatically persists to additional properties, even when openapi version is specified")
+    public void allowsProgrammaticallySettingArtifactVersionWithSpecifiedOpenApiVersion() {
+        final P_AbstractJavaCodegen codegen = new P_AbstractJavaCodegen();
+        final String version = "9.8.7-rc1";
+        codegen.setArtifactVersion(version);
+
+        OpenAPI api = TestUtils.createOpenAPI();
+        api.getInfo().setVersion("1.2.3-SNAPSHOT");
+        codegen.processOpts();
+        codegen.preprocessOpenAPI(api);
+
+        Assert.assertEquals(codegen.getArtifactVersion(), version);
+        Assert.assertEquals(codegen.additionalProperties().get(CodegenConstants.ARTIFACT_VERSION), version);
+    }
+
+    @Test(description = "tests if a null in addition properties artifactVersion results in default version")
+    public void usesDefaultVersionWhenAdditionalPropertiesVersionIsNull() {
+        final P_AbstractJavaCodegen codegen = new P_AbstractJavaCodegen();
+        final String version = "1.0.0";
+
+        OpenAPI api = TestUtils.createOpenAPI();
+        api.getInfo().setVersion(null);
+        codegen.setArtifactVersion(null);
+        codegen.additionalProperties().put(CodegenConstants.ARTIFACT_VERSION, null);
+
+        codegen.processOpts();
+        codegen.preprocessOpenAPI(api);
+
+        Assert.assertEquals(codegen.getArtifactVersion(), version);
+        Assert.assertEquals(codegen.additionalProperties().get(CodegenConstants.ARTIFACT_VERSION), version);
+    }
+
+
+
     @Test(description = "tests if default version with snapshot is used when setArtifactVersion is used")
     public void snapshotVersionAlreadySnapshotTest() {
         final P_AbstractJavaCodegen codegen = new P_AbstractJavaCodegen();

samples/server/petstore/java-pkmst/.openapi-generator/VERSION

@@ -1 +1 @@
-4.0.0-SNAPSHOT
+4.2.2-SNAPSHOT

samples/server/petstore/java-pkmst/pom.xml

@@ -232,7 +232,7 @@
       <dependency>
             <groupId>org.threeten</groupId>
             <artifactId>threetenbp</artifactId>
-            <version>1.3.6</version>
+            <version>1.4.0</version>
       </dependency>
    </dependencies>
    <dependencyManagement>

samples/server/petstore/java-pkmst/src/main/java/com/prokarma/pkmst/controller/PetApi.java

@@ -1,5 +1,5 @@
 /**
- * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech) (4.0.0-SNAPSHOT).
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech) (4.2.2-SNAPSHOT).
  * https://openapi-generator.tech
  * Do not edit the class manually.
  */

samples/server/petstore/java-pkmst/src/main/java/com/prokarma/pkmst/controller/StoreApi.java

@@ -1,5 +1,5 @@
 /**
- * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech) (4.0.0-SNAPSHOT).
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech) (4.2.2-SNAPSHOT).
  * https://openapi-generator.tech
  * Do not edit the class manually.
  */

samples/server/petstore/java-pkmst/src/main/java/com/prokarma/pkmst/controller/UserApi.java

@@ -1,5 +1,5 @@
 /**
- * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech) (4.0.0-SNAPSHOT).
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech) (4.2.2-SNAPSHOT).
  * https://openapi-generator.tech
  * Do not edit the class manually.
  */

samples/server/petstore/java-pkmst/src/main/java/com/prokarma/pkmst/model/Pet.java

@@ -26,7 +26,7 @@ public class Pet   {
   private Long id;
 
   @JsonProperty("category")
-  private Category category = null;
+  private Category category;
 
   @JsonProperty("name")
   private String name;