Include Java-from-Code schema generator example

Author: CarstenWickner

implementations.md

@@ -149,6 +149,8 @@ For example, the only incompatibilities between draft-04 and draft-06 involve `e
     -   [typescript-json-schema](https://github.com/YousefED/typescript-json-schema)
 -   Python
     -   [Pydantic](https://pydantic-docs.helpmanual.io/) (MIT) - generates schemas from Python models based on Python 3.6+ type hints.
+-   Java
+    -   [jsonschema-generator](https://github.com/victools/jsonschema-generator) (Apache 2.0) - generates schemas from Java types
 
 #### From data