Fory JSON

Fory JSON is Apache Fory's thread-safe Java JSON codec. It provides interpreted and runtime-generated codecs for Java objects, records, immutable creator-based classes, common JDK types, generic containers, custom complete-value codecs, and finite annotation-declared polymorphism.

Fory JSON is a separate data format from Fory's binary native and xlang protocols. Use it when a system must exchange ordinary JSON with browsers, APIs, logs, configuration, or another JSON implementation. Use the Fory binary protocol when you need cross-language schema metadata, reference identity, circular graphs, or Fory's binary-only features.

Documentation map

Goal	Page
First runnable JSON round trip	Getting Started
Understand Java object mapping and configuration	Object Mapping
Configure properties, creators, values, validators, and subtypes	Annotations
Extend complete values, children, and map keys	Custom Codecs
Deploy on Android	Android
Build a GraalVM native image	GraalVM Native Image
Decode input safely	Security
Diagnose failures	Troubleshooting

Limits and unsupported features

Fory JSON intentionally has a smaller semantic surface than the Fory binary protocol and general Jackson object mapping:

• no shared-reference identity or circular-reference protocol;
• no open polymorphism, JSON class-name IDs, runtime subtype discovery, or runtime subtype table extension;
• no InputStream parser or incremental OutputStream writer on the ForyJson root API;
• no pretty-print configuration;
• no Jackson/Gson annotation compatibility layer;
• no aliases, views, filters, injection, managed/back references, object identity annotations, or root wrapping;
• no Fory core Expose processing.

Circular graphs eventually fail maxDepth; they are not reconstructed. Use Fory core's binary native or xlang protocol when reference identity or cycles are required.

Related Java guides

For binary serialization, start with Java Object Serialization and choose xlang or native. Binary builder options are documented separately in Java Configuration.