From this comment on the old mailing list it looks like the easiest option would be to use JNI to interact with Julia via its C API, combined with JavaCall.jl on the Julia side to handle the conversions (this is roughly analogous to how pyjulia works, using PyCall.jl on the Julia side).
As I mentioned on another thread:
Unfortunately, bindings from external languages aren’t the most popular thing for people to voluntarily work on, since “people who like to write Julia code” don’t directly benefit themselves from that work