I was talking to some cat last night, and he said something about JavaSynth (spelling?) being really great. I know another person who did a modularized version of CSound using Java resources. My take on the subject is that Java is great for some things, but as I believe someone noted on this list, the Java honeymoon is over. I'm personally a fan of C++. Perhaps a good approach would be to do the guts of your app(s) in portable C++, recompiling as needed for target platforms, and then do the front end in Java. Maybe this will give you the best of both worlds.
Ben,
Sometimes you can't write a chord ugly enough to say what you want, so you have to rely on a giraffe filled with whipped cream. --Frank Zappa