As Java 7 has been launched these days, the question arises real soon: “Does Adobe support Java 7 as runtime for CQ5?”.
So, the clear answer is: No, it isn’t supported. Mostly because of some issues which can cause corruptions in the Lucene index. So, of course, you give it a try and tackle the risk yourself (as you can run CQ5 on a Windows 7 box or on Debian Linux); but don’t complain, if you receive some strange behaviour.
ps: Just adding
-XX:-UseLoopPredicate to your JVM parameters won’t solve the problem (according to the Lucene Website).