The Deimos Project is a Java-based game development library collection. Includes Vertex Modeler, a 3D modeler that lets you programatically define models using Java source code. The modeler is also a simple scene graph API.
XMUD is a MMORPG implementation in Java. Players can extend the system by creating new objects. The game provides a 3D engine written in Java3D, Persistent state management, synchronization and networking subsystems. Compatible with NWN modules.