A simple expressive web framework for java. Spark has a kotlin DSL https://github.com/perwendel/spark-kotlin

A JSON Schema validation implementation in pure Java, which aims for correctness and performance, in that order

Lightweight Java State Machine

Rare, hard-to-write utilities that are thoroughly tested

Functional programming language for JVM.

Clojure plugin for IntelliJ IDEA

Java runtime for Barrister RPC

Domain neutral services for Java - including NoSQL persistence

Java tools to copy Amazon S3 and SimpleDB data