pull · Sep 20, 2026 · Sep 20, 2026 · Sep 20, 2026 · Sep 20, 2026 · Sep 20, 2026
diff --git a/.github/workflows/samples-java-client-jdk17.yaml b/.github/workflows/samples-java-client-jdk17.yaml
@@ -17,6 +17,7 @@ on:
       - samples/client/petstore/java/webclient-useSingleRequestParameter/**
       - samples/client/others/java/restclient-enum-in-multipart/**
       - samples/client/others/java/restclient-sealedInterface/**
+      - samples/client/others/java/restclient-jackson-default-impl/**
       - samples/client/others/java/restclient-useAbstractionForFiles/**
       - samples/client/petstore/java/jersey3-oneOf/**
       - samples/client/petstore/java/jersey3-jackson3/**
@@ -37,6 +38,7 @@ on:
       - samples/client/petstore/java/webclient-useSingleRequestParameter/**
       - samples/client/others/java/restclient-enum-in-multipart/**
       - samples/client/others/java/restclient-sealedInterface/**
+      - samples/client/others/java/restclient-jackson-default-impl/**
       - samples/client/others/java/restclient-useAbstractionForFiles/**
       - samples/client/petstore/java/jersey3-oneOf/**
       - samples/client/petstore/java/jersey3-jackson3/**
@@ -72,6 +74,7 @@ jobs:
           - samples/client/petstore/java/webclient-useSingleRequestParameter
           - samples/client/others/java/restclient-enum-in-multipart
           - samples/client/others/java/restclient-sealedInterface
+          - samples/client/others/java/restclient-jackson-default-impl
           - samples/client/others/java/restclient-useAbstractionForFiles
           - samples/client/petstore/java/jersey3-oneOf
           - samples/client/petstore/java/jersey3-jackson3

diff --git a/.github/workflows/samples-jdk17.yaml b/.github/workflows/samples-jdk17.yaml
@@ -20,6 +20,7 @@ on:
       - samples/openapi3/server/petstore/springboot-3-include-http-request-context/**
       - samples/server/petstore/springboot-x-implements-skip/**
       - samples/server/petstore/java-camel/**
+      - samples/server/petstore/java-camel-oneof-jackson-default-impl/**
       - samples/server/petstore/java-helidon-server/v3/mp/**
       - samples/server/petstore/java-helidon-server/v3/se/**
       - samples/server/petstore/jaxrs-spec-sealed/**
@@ -45,6 +46,7 @@ on:
       - samples/openapi3/server/petstore/springboot-3-include-http-request-context/**
       - samples/server/petstore/springboot-x-implements-skip/**
       - samples/server/petstore/java-camel/**
+      - samples/server/petstore/java-camel-oneof-jackson-default-impl/**
       - samples/server/petstore/java-helidon-server/v3/mp/**
       - samples/server/petstore/java-helidon-server/v3/se/**
       - samples/server/petstore/jaxrs-spec-sealed/**
@@ -76,6 +78,7 @@ jobs:
           - samples/openapi3/server/petstore/springboot-3-include-http-request-context
           - samples/server/petstore/springboot-x-implements-skip
           - samples/server/petstore/java-camel/
+          - samples/server/petstore/java-camel-oneof-jackson-default-impl
           - samples/server/petstore/java-helidon-server/v3/mp/
           - samples/server/petstore/java-helidon-server/v3/se
           - samples/server/petstore/jaxrs-spec-sealed

diff --git a/.github/workflows/samples-kotlin-client.yaml b/.github/workflows/samples-kotlin-client.yaml
@@ -9,6 +9,7 @@ on:
       - samples/client/others/kotlin-jvm-spring-3-restclient-nullable-return/**
       - samples/client/others/kotlin-oneOf-anyOf-kotlinx-serialization*/**
       - samples/client/others/kotlin-oneOf-discriminator-kotlinx-serialization*/**
+      - samples/client/others/kotlin-oneof-jackson-default-impl/**
   pull_request:
     paths:
       - 'samples/client/petstore/kotlin*/**'
@@ -17,6 +18,7 @@ on:
       - samples/client/others/kotlin-jvm-spring-3-restclient-nullable-return/**
       - samples/client/others/kotlin-oneOf-anyOf-kotlinx-serialization*/**
       - samples/client/others/kotlin-oneOf-discriminator-kotlinx-serialization*/**
+      - samples/client/others/kotlin-oneof-jackson-default-impl/**
 
 jobs:
   build:
@@ -82,6 +84,7 @@ jobs:
           - samples/client/others/kotlin-integer-enum
           - samples/client/petstore/kotlin-allOf-discriminator-kotlinx-serialization
           - samples/client/others/kotlin-oneOf-discriminator-kotlinx-serialization
+          - samples/client/others/kotlin-oneof-jackson-default-impl
           - samples/client/others/kotlin-oneOf-anyOf-kotlinx-serialization
           - samples/client/others/kotlin-oneOf-anyOf-kotlinx-serialization-nonPublicApi
           - samples/client/others/kotlin-oneOf-anyOf-kotlinx-serialization-explicitApi

diff --git a/.github/workflows/samples-kotlin-server-jdk17.yaml b/.github/workflows/samples-kotlin-server-jdk17.yaml
@@ -14,6 +14,7 @@ on:
       - 'samples/server/petstore/kotlin-spring-sealed-interfaces/**'
       - 'samples/server/petstore/kotlin-springboot-sort-validation/**'
       - 'samples/server/petstore/kotlin-springboot-paged-model/**'
+      - 'samples/server/petstore/kotlin-spring-oneof-jackson-default-impl/**'
       - 'samples/server/petstore/kotlin-server/ktor-delegate-pattern/generated/**'
       # comment out due to gradle build failure
       # - samples/server/petstore/kotlin-spring-default/**
@@ -30,6 +31,7 @@ on:
       - 'samples/server/petstore/kotlin-spring-sealed-interfaces/**'
       - 'samples/server/petstore/kotlin-springboot-sort-validation/**'
       - 'samples/server/petstore/kotlin-springboot-paged-model/**'
+      - 'samples/server/petstore/kotlin-spring-oneof-jackson-default-impl/**'
       - 'samples/server/petstore/kotlin-server/ktor-delegate-pattern/generated/**'
       # comment out due to gradle build failure
       # - samples/server/petstore/kotlin-spring-default/**
@@ -75,6 +77,7 @@ jobs:
           - samples/server/petstore/kotlin-spring-declarative-interface-reactive-reactor-wrapped
           - samples/server/petstore/kotlin-spring-declarative-interface-wrapped
           - samples/server/petstore/kotlin-spring-sealed-interfaces
+          - samples/server/petstore/kotlin-spring-oneof-jackson-default-impl
           - samples/server/petstore/kotlin-springboot-sort-validation
           - samples/server/petstore/kotlin-springboot-paged-model
           # comment out due to gradle build failure

diff --git a/.github/workflows/samples-spring-jdk17.yaml b/.github/workflows/samples-spring-jdk17.yaml
@@ -21,6 +21,7 @@ on:
       - samples/server/others/springboot-pre-authorize/**
       - samples/openapi3/server/petstore/spring-boot-oneof-sealed/**
       - samples/openapi3/server/petstore/spring-boot-oneof-interface/**
+      - samples/openapi3/server/petstore/spring-boot-oneof-jackson-default-impl/**
       - samples/client/petstore/spring-http-interface-oauth/**
   pull_request:
     paths:
@@ -42,6 +43,7 @@ on:
       - samples/server/others/springboot-pre-authorize/**
       - samples/openapi3/server/petstore/spring-boot-oneof-sealed/**
       - samples/openapi3/server/petstore/spring-boot-oneof-interface/**
+      - samples/openapi3/server/petstore/spring-boot-oneof-jackson-default-impl/**
       - samples/client/petstore/spring-http-interface-oauth/**
 jobs:
   build:
@@ -71,6 +73,7 @@ jobs:
           - samples/server/others/springboot-pre-authorize
           - samples/openapi3/server/petstore/spring-boot-oneof-sealed
           - samples/openapi3/server/petstore/spring-boot-oneof-interface
+          - samples/openapi3/server/petstore/spring-boot-oneof-jackson-default-impl
           - samples/client/petstore/spring-http-interface-oauth
     steps:
       - uses: actions/checkout@v7

diff --git a/bin/configs/java-camel-oneof-jackson-default-impl.yaml b/bin/configs/java-camel-oneof-jackson-default-impl.yaml
@@ -0,0 +1,25 @@
+generatorName: java-camel
+outputDir: samples/server/petstore/java-camel-oneof-jackson-default-impl
+inputSpec: modules/openapi-generator/src/test/resources/3_0/jackson-default-impl-oneof.yaml
+templateDir: modules/openapi-generator/src/main/resources/java-camel-server
+globalProperties:
+  apiTests: "false"
+  modelTests: "false"
+additionalProperties:
+  hideGenerationTimestamp: true
+  artifactId: java-camel-oneof-jackson-default-impl
+  camelRestBindingMode: "auto"
+  performBeanValidation: true
+  camelDataformatProperties: "json.out.disableFeatures=WRITE_DATES_AS_TIMESTAMPS"
+  jackson: true
+  camelUseDefaultValidationErrorProcessor: true
+  camelRestClientRequestValidation: true
+  camelSecurityDefinitions: true
+  implicitHeaders: true
+  useSpringBoot3: false
+  useOneOfInterfaces: "true"
+  useDeductionForOneOfInterfaces: "true"
+  generateJsonIncludeAnnotations: "true"
+  generateJsonSetterNullsAnnotations: "true"
+  typeInfoDefaultImpls:
+    Fruit: Apple
diff --git a/bin/configs/java-restclient-jackson-default-impl.yaml b/bin/configs/java-restclient-jackson-default-impl.yaml
@@ -0,0 +1,12 @@
+generatorName: java
+outputDir: samples/client/others/java/restclient-jackson-default-impl
+library: restclient
+inputSpec: modules/openapi-generator/src/test/resources/3_0/jackson-default-impl-oneof.yaml
+templateDir: modules/openapi-generator/src/main/resources/Java
+additionalProperties:
+  artifactId: restclient-jackson-default-impl
+  hideGenerationTimestamp: "true"
+  useOneOfInterfaces: "true"
+  useDeductionForOneOfInterfaces: "true"
+  typeInfoDefaultImpls:
+    Fruit: Apple
diff --git a/bin/configs/kotlin-oneof-jackson-default-impl.yaml b/bin/configs/kotlin-oneof-jackson-default-impl.yaml
@@ -0,0 +1,12 @@
+generatorName: kotlin
+outputDir: samples/client/others/kotlin-oneof-jackson-default-impl
+inputSpec: modules/openapi-generator/src/test/resources/3_0/jackson-default-impl-oneof.yaml
+templateDir: modules/openapi-generator/src/main/resources/kotlin-client
+additionalProperties:
+  artifactId: kotlin-oneof-jackson-default-impl
+  serializationLibrary: jackson
+  library: jvm-retrofit2
+  enumUnknownDefaultCase: true
+  useOneOfInterfaces: "true"
+  typeInfoDefaultImpls:
+    Fruit: Apple
diff --git a/bin/configs/kotlin-spring-oneof-jackson-default-impl.yaml b/bin/configs/kotlin-spring-oneof-jackson-default-impl.yaml
@@ -0,0 +1,18 @@
+generatorName: kotlin-spring
+outputDir: samples/server/petstore/kotlin-spring-oneof-jackson-default-impl
+library: spring-boot
+inputSpec: modules/openapi-generator/src/test/resources/3_0/jackson-default-impl-oneof.yaml
+templateDir: modules/openapi-generator/src/main/resources/kotlin-spring
+additionalProperties:
+  artifactId: kotlin-spring-oneof-jackson-default-impl
+  documentationProvider: none
+  annotationLibrary: none
+  useSwaggerUI: "false"
+  interfaceOnly: "true"
+  useSpringBoot3: "true"
+  useOneOfInterfaces: "true"
+  useDeductionForOneOfInterfaces: "true"
+  generateJsonIncludeAnnotations: "true"
+  generateJsonSetterNullsAnnotations: "true"
+  typeInfoDefaultImpls:
+    Fruit: Apple
diff --git a/bin/configs/spring-boot-oneof-jackson-default-impl.yaml b/bin/configs/spring-boot-oneof-jackson-default-impl.yaml
@@ -0,0 +1,16 @@
+generatorName: spring
+outputDir: samples/openapi3/server/petstore/spring-boot-oneof-jackson-default-impl
+inputSpec: modules/openapi-generator/src/test/resources/3_0/jackson-default-impl-oneof.yaml
+templateDir: modules/openapi-generator/src/main/resources/JavaSpring
+additionalProperties:
+  groupId: org.openapitools.openapi3
+  documentationProvider: springdoc
+  artifactId: springboot-oneof-jackson-default-impl
+  snapshotVersion: "true"
+  hideGenerationTimestamp: "true"
+  useOneOfInterfaces: "true"
+  useDeductionForOneOfInterfaces: "true"
+  generateJsonIncludeAnnotations: "true"
+  generateJsonSetterNullsAnnotations: "true"
+  typeInfoDefaultImpls:
+    Fruit: Apple
diff --git a/bin/configs/spring-http-interface-reactive-noResponseEntity.yaml b/bin/configs/spring-http-interface-reactive-noResponseEntity.yaml
@@ -18,4 +18,5 @@ additionalProperties:
   #  performBeanValidation should default to "false" when not specified
   useResponseEntity: "false"
   useSpringBoot3: "true"
+  useTags: "true"
 
diff --git a/bin/configs/spring-http-interface-reactive.yaml b/bin/configs/spring-http-interface-reactive.yaml
@@ -17,4 +17,4 @@ additionalProperties:
   #  useBeanValidation should default to "false" when not specified
   #  performBeanValidation should default to "false" when not specified
   useSpringBoot3: "true"
-
+  useTags: "true"
diff --git a/bin/configs/spring-http-interface-useHttpServiceProxyFactoryInterfacesConfiguration.yaml b/bin/configs/spring-http-interface-useHttpServiceProxyFactoryInterfacesConfiguration.yaml
@@ -18,3 +18,4 @@ additionalProperties:
   performBeanValidation: "true"
   useHttpServiceProxyFactoryInterfacesConfigurator: "true"
   useSpringBoot3: "true"
+  useTags: "true"
diff --git a/bin/configs/spring-http-interface.yaml b/bin/configs/spring-http-interface.yaml
@@ -18,3 +18,4 @@ additionalProperties:
   #  useBeanValidation should default to "false" when not specified
   #  performBeanValidation should default to "false" when not specified
   useSpringBoot3: "true"
+  useTags: "true"
diff --git a/docs/generators/java-camel.md b/docs/generators/java-camel.md
@@ -113,6 +113,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |substituteGenericPagedModel|Detect schemas that represent paginated responses (an object with a 'content' array property and a 'page' pagination-metadata property) and replace their generated references with PagedModel&lt;T&gt;. By default this uses a generated type in the config package (default 'org.openapitools.configuration'), but `importMappings.PagedModel` can override it to a custom/FQCN-mapped type. The detected page schemas and the pagination metadata schema are suppressed from code generation.| |false|
 |testOutput|Set output folder for models and APIs tests| |${project.build.directory}/generated-test-sources/openapi|
 |title|server title name or client service name| |OpenAPI Spring|
+|typeInfoDefaultImpls|Map of schema name to default Jackson deserialization class for @JsonTypeInfo(defaultImpl=...). Applies to both deduction-based and discriminator-based oneOf interfaces. Overrides x-jackson-default-impl when both are set for the same schema. Example: yaml `typeInfoDefaultImpls: {PostRegistrationRequest: PostRegistrationBasicRequest}`| |empty map|
 |unhandledException|Declare operation methods to throw a generic exception and allow unhandled exceptions (useful for Spring `@ControllerAdvice` directives).| |false|
 |useBeanValidation|Use BeanValidation API annotations| |true|
 |useDeductionForOneOfInterfaces|Annotate discriminator-free oneOf interfaces with Jackson's @JsonTypeInfo(use = Id.DEDUCTION) and @JsonSubTypes so the concrete subtype is resolved from the JSON field set rather than a type-tag property. Has no effect when a discriminator is present (name-based resolution is used instead). Requires subtypes to have structurally distinct sets of properties.| |false|
@@ -159,6 +160,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |x-minimum-message|Add this property whenever you need to customize the invalidation error message for the minimum value of a variable|FIELD, OPERATION_PARAMETER|null
 |x-maximum-message|Add this property whenever you need to customize the invalidation error message for the maximum value of a variable|FIELD, OPERATION_PARAMETER|null
 |x-spring-api-version|Value for 'version' attribute in @RequestMapping (for Spring 7 and above).|OPERATION|null
+|x-jackson-default-impl|Specifies the default implementation class name for Jackson @JsonTypeInfo(defaultImpl=...) on a oneOf interface schema (deduction-based or discriminator-based). Can be overridden per-schema by the `typeInfoDefaultImpls` generator option.|MODEL|null
 |x-jackson-json-include-policy|Manually override the resolved Jackson `@JsonInclude` policy for this property. Must be one of `ALWAYS`, `NON_NULL`, `NON_ABSENT`, `NON_EMPTY`, `NON_DEFAULT`, `USE_DEFAULTS`, `CUSTOM`, or `NONE` to emit no annotation. Always wins over the automatic required/nullable matrix and the `optionalNonNullPropertyJsonInclude` option.|FIELD|resolved automatically per the required/nullable matrix
 |x-jackson-json-setter-nulls|Manually override the resolved Jackson `@JsonSetter(nulls = ...)` deserialization null-handling for this property. Must be one of `SKIP` (ignore an explicit JSON null, keeping the default), `FAIL` (reject an explicit JSON null), or `NONE` to emit no annotation. Always wins over the automatic `openApiNullable` default and the `optionalNonNullPropertyJsonSetterNulls` option, and is honored regardless of `generateJsonSetterNullsAnnotations` or whether the property is required/nullable.|FIELD|resolved automatically per the openApiNullable default
 

diff --git a/docs/generators/java.md b/docs/generators/java.md
@@ -94,6 +94,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |supportUrlQuery|Generate toUrlQueryString in POJO (default to true). Available on `native`, `apache-httpclient` libraries.| |false|
 |supportVertxFuture|Also generate api methods that return a vertx Future instead of taking a callback. Only `vertx` supports this option. Requires vertx 4 or greater.| |false|
 |testOutput|Set output folder for models and APIs tests| |${project.build.directory}/generated-test-sources/openapi|
+|typeInfoDefaultImpls|Map of schema name to default Jackson deserialization class for @JsonTypeInfo(defaultImpl=...). Applies to both deduction-based and discriminator-based oneOf interfaces. Overrides x-jackson-default-impl when both are set for the same schema. Example: yaml `typeInfoDefaultImpls: {PostRegistrationRequest: PostRegistrationBasicRequest}`| |empty map|
 |useAbstractionForFiles|Use alternative types instead of java.io.File to allow passing bytes without a file on disk. Available on resttemplate, webclient, restclient, libraries| |false|
 |useBeanValidation|Use BeanValidation API annotations| |false|
 |useDeductionForOneOfInterfaces|Annotate discriminator-free oneOf interfaces with Jackson's @JsonTypeInfo(use = Id.DEDUCTION) and @JsonSubTypes so the concrete subtype is resolved from the JSON field set rather than a type-tag property. Has no effect when a discriminator is present (name-based resolution is used instead). Requires subtypes to have structurally distinct sets of properties.| |false|
@@ -131,6 +132,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |x-class-extra-annotation|Custom annotation(s) to be added to model; accepts a string or list of strings|MODEL|null
 |x-field-extra-annotation|Custom annotation(s) to be added to property; accepts a string or list of strings|FIELD, OPERATION_PARAMETER|null
 |x-webclient-blocking|Specifies if method for specific operation should be blocking or non-blocking(ex: return `Mono<T>/Flux<T>` or `return T/List<T>/Set<T>` & execute `.block()` inside generated method)|OPERATION|false
+|x-jackson-default-impl|Specifies the default implementation class name for Jackson @JsonTypeInfo(defaultImpl=...) on a oneOf interface schema (deduction-based or discriminator-based). Can be overridden per-schema by the `typeInfoDefaultImpls` generator option.|MODEL|null
 
 
 ## IMPORT MAPPING