Java 1.1, Java 2 & Java ME (MIDP 1.0) compatible. Great for making games that compatible with Java 1.1, and also for making mobile games. Still actively developed. http://www.genuts.com/
Genuine Advantage Gaming Engine, a high performance 2D wrappers, and low latency sound handling. The creator of the famous precise timing, GAGE Timer. Very slow in development. http://java.dnsalias.com/
JCraft is a free cross-platform isometric, tilebased real-time strategy game engine. It includes support for playing over the internet/LAN, or playing a computer opponent. The engine is configurable and can be used to create games with a wide-range of features specific to your needs. http://www.nullpointer.ch/projects/JCraft/