Balaftuna is an XY MIDI controller. You can assign to it the MIDI Event you like for the X coordinate, the MIDI Event you like for the Y coordinate.
bcr steps is a MIDI step sequencer and arpeggiator modelled on the Behringer BCR2000 interface (lots of knobs). It integrates with a BCR2000 as well as other MIDI controllers.
Juke is a simple MIDI/RMF player in Java.
JukeCon is a simple console MIDI/RMF player in Java.
allows you to directly edit the events in a Midi file. It is intended to make it easy to find and fix problems, such as setting volume and pan values for a track, without the need for a complex Midi sequencing program
a karaoke player that runs on any architecture that can run java. It plays both midi (.mid and .kar) and mp3+cdg files
RasmusDSP is an embeddable Audio/MIDI processor. It contains various filters and generators (including SoundFont 2.0 compatible synthesizer). Has a script interpreter which is used to describe instruments, route Audio/MIDI signal between processor units.
a graphical user-friendly score editor interface for LilyPond