My Christmas present, some codebases under the GPL for 3D games, look at asteris http://code.google.com/p/asteris/downloads/list (it includes jumping now with the z key) for enlarging the codebases :
Final fantasy 2 , rather poorly written but OK :
http://code.google.com/p/angels-destiny-rpg/downloads/list
3D JOGL game :
http://code.google.com/p/spaceodyssey3d/downloads/list
LWGJL codebase :
http://code.google.com/p/demonworld/downloads/list
Enjoy!