Feign makes writing java http clients easier
A fast JSON parser/generator for Java.
Generate Java types from JSON or JSON Schema and annotates those types for data-binding with Jackson, Gson, etc
Java JsonPath implementation
A reference implementation of a JSON package in Java.
Logback JSON encoder and appenders
A JSON Schema validation implementation in pure Java, which aims for correctness and performance, in that order
JSON Schema validator for java, based on the org.json API
JSON to JSON transformation library written in Java.