Well, I tested as I promised. BEA JRockit hadn't problems with handling JDIC library - it is just better at ignoring staff that it doesn't handle. But I've noticed problems with rendering pieces. I examined through a game, or played, not sure :), and all of the sudden I got just the raw silhouettes of the pieces. It looked bad. Is it a surprise that Sun's Java is a winner in this test?
I still struggle to create a JBughousePiecePanel thingy. It will (hopefully soon) render pieces available for both players to drop on the board. I dream to say someday "Happy dropping!".