JGame is a Java gamming engine, it's main goal is for quikly building games in Java for use on Windows, Mac, Linux, and eventually Android.
There is still works that needs to be done, but there is some decent functionality to make the most basic of games.
The source comes with an example Space Shooter game (Which isn't really in space), but it shows that you have the abillity to set key events, collision events, dynamic object creation, and a few more behind the scense functionality.
As the Library expands so will the example(s).