A "Jack" capability for Linux users has been requested. Please figure out what this would entail, then design and implement.
I vote for this one.
I vote for this, too. Lack of Jack (or ALSA) is a bit of a nuisance.
There are some java jack wrappers around, which presumably should help, though I don't know which work well :-/
JNAJack is mentioned on the Jackaudio site as useable with the Windows version of Jack, which suggests to me that it may be the most suitable tool:
The Jack API documentation is here:
though I don't know how well that relates to the java interfaces.
IMHO Inpro-Visor would really only need a MIDI output, though I could see a midi-input and the means to sync In/Out may be useful. Others may have other views.