MoZo1 -3 Junior Poster

I have a database application in Java. They want to access the data from primarily Excel2007 and secondarily Visual basic. I need some advice about with what library could I easily add this functionality. I've tried Simple OLE DB Provider with some JNI, but it's unstable and I'm... grrr. So could sby advise a better standard these win programs could use? JNI and local port TCP/IP is welcome, ActiveX is acceptable.
Thanks!