I use processing and java a fair bit at the moment to do mostly MIDI related stuff, and I was a bit annoyed by the libraries I was using. I wrote a OSX MIDI wrapper a while back, which allows you to have access to MIDI in Java under OSX, you can get it here:
link
I also wrote a simple, lean and mean MIDI Library for Java (and Processing) which works under Linux, Windows and Macosx and (most importantly for me) provides unbroken Sysex Message on every OS as well. You can get it here:
link
Cheers, I know some peepz around it use p5
