I have just made an alpha release of an Ada binding to Java JNI
It is called "Cafe 1815" (I have previously referred to this as Javelin
- but that name turned out to be not exactly unique).

Cafe 1815 is an interface to the low level JNI, not a binding to
directly to the
Java class libraries (I have another package in the works called Cafe
that does that).

Also, it is not as finished as I would like, but it is still useful.
I used it to write a java launcher completely in Ada.

See: http://www.acenet.com.au/~gbull