Java 7 is now full release. There do seem to be some issues with the latest update on Java 6, and it is known to cause crashes in Opera. For that reason I changed to Java 7, which works fine. The very quick release of J7 after a J6 update suggests there may be other issues and I suspect it won't be long before the J6 ones are dropped.
When I upgraded [cough] from Java 6 to Java 7 (can't remember which version) some days ago I found that the BT Performance Tester for one wouldn't "work" just got a BT error page so went back to Java 6 and it ran OK, just wish the connection could be faster