thx for your quick replies.
As Kev pointed out right, I have no frickin clue. That's why I study it
and code samples are very very useful. If somebody knows some post it here! In order to find some I searched the web for examples and luckily found some. A good one can be found there: http://nehe.gamedev.net/data/lessons/lesson.asp?lesson=30
and if the jogl port is not working here are the whole port's for all nehe tuts: http://pepijn.fab4.be/nehe/
It's not a simple one but a very good one.
Btw I changed back to jogl because the lack of behaviour in xith3d. So I am looking forward to see it or something similar implemented
The other time I tried a little bit around, which you can see it here: http://mitglied.lycos.de/redries/jogl/Kollision.java
It's not good and finished, but a first try in order to get collision detection with bsp trees