I posted up a quick terrain demo on Javagaming.org not so long ago; I just thought you might be interested in it:
http://www.javagaming.org/samplecode/Terrain.zip
Requires a Geforce 1+ to run I’m afraid. Also requires JRE1.4 (beta available from Sun). Yes, it’s written in Java. No, it’s not slow.
Do read the readme.
Cas