I'm wondering if it will work under OpenJDK on Linux when multiple sounds are played at once? I've seen other users from JGO report issues with using Clip in this way.
Don't use Clip, period! They perform horribly everywhere for doing this sort of thing, though particularly noticeable on Linux, because they open a line to the soundcard for every sound. Simply open a single audio line and mix all sounds to it, or even simpler use a library that already does this - eg. TinySound.
Also, what's the deal with all those Threads? Sorry, but this code should be mercifully euthanised!