GNU Classpath + PhoneME + SDLJava + cacao/jamvm/kaffe = MIDPath
MIDPath provides a MIDP2 implementation on top of the SDL and SDLJava libraries. It targets free JVMs working with GNU Classpath: Cacao, Kaffe, JamVM. The code is based on phoneME, the free implementation of MIDP2 from Sun. MIDPath is released under the GPL.
Now you can play all those cool java phone games on your desktop using free sofware :)