fory-annotation-processor generates static serializers for Java classes annotated with @ForyStruct. For Fory JSON it processes direct @JsonType models and @JsonMixin(target = ...) declarations. Direct models receive their existing type-owned JSON companion when required. A non-empty Mixin receives exact platform configuration and a pair-specific companion when generated target operations are available. Generated companions call effective @JsonValidator methods directly after the model is completely populated. Runtime codec resolution, including registered and built-in codecs, still decides whether those operations are used. The generated rules retain the complete effective annotation surface, matched target declarations, generic endpoints, subtype and unwrapped models, validators, and selected codec constructors. An empty Mixin produces no output. All outputs are generated by javac during the application build.

Use this processor for:

• Android applications.
• ordinary JVM applications using ForyJsonBuilder#withCodegen(false).
• Android model classes that use Fory type-use annotations such as @Ref, @UInt8Type, or @Float16Type.
• Fory JSON object models that need direct member access, JsonValidator calls, Android Record support, GraalVM metadata, or automatic R8 rules.

For GraalVM native images, use the processor for every reachable @JsonType JSON model and @JsonMixin source, and use Fory's native-image build-time serializer generation for ordinary Fory serialization. A directly annotated validator model must use @JsonType; a validator contributed by a Mixin uses the generated exact Mixin-target pair.

The processor is an opt-in build tool. Applications add it to their annotation-processor path. The processor has no production dependency on fory-core or fory-json; generated sources compile against the corresponding runtime artifact already used by the application.

A Mixin source declares exactly one target. The processor may generate pair artifacts for multiple sources that name the same target because they are alternative runtime configurations. One ForyJsonBuilder enables one source per exact target, and a later registration replaces an earlier one before build() snapshots the mapping. The processor never merges multiple sources and never changes the direct companion path without a Mixin. A source must be named, must not be local or anonymous, and must not extend another source or implement interfaces, so there is no second annotation-precedence hierarchy.

JsonMixin supports the Fory JSON mapping and validation annotations, including JsonValidator. JsonType remains a direct build-time marker and cannot be added or removed through a Mixin. The processor does not duplicate the runtime's built-in codec selection.

For ordinary Fory JSON object models on Android, @JsonType is optional. A model without it can use application-authored exact R8 rules and reflection. Android builds that need desugared Java Record construction require processor-generated operations from either a direct @JsonType declaration or a compiled exact @JsonMixin pair, because generated code calls the canonical constructor and component accessors directly. This includes a Record using a String JsonValue representation and an annotated canonical constructor. @JsonCodec uses ordinary type, field, method, and parameter annotations, so every supported codec member remains available through reflection with equivalent rules. See docs/object-serialization/java/android.md.

Android models with direct JsonValidator methods use @JsonType so the processor can emit direct calls and exact retention rules. Third-party targets receive the same support from a compiled exact JsonMixin pair. Complete custom codecs and JsonCreator implementations that perform validation themselves do not require a generated validator call.

For the full user-facing guides, see docs/object-serialization/java/static-generated-serializers.md and docs/json/index.md.