It is already there!
gsc -c -target java foo.scm
Performance however is atrocious… something like two or three orders of magnitude slower than with the C backend. We’re currently looking into the issue and our current guess is that the Java JIT compiler is misbehaving.
The supported target languages are c, js, python, ruby and java. Currently the ruby target is experiencing problems, but probably an easy fix when I look into it (it was working fine before some recent refactoring).
Marc