Have a look here…
http://download.java.net/jdk6/6u10/promoted/b08/changes/jdk6uN-b08.html
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6622332
Remember that you need FF3 or IE 6/7 to run it. I imagine a backport to FF2 in a while.
already playing with it - doesn’t seem to break anything (you need to turn it on in the control panel) - but no documentation found - so you have to decompile plugin.jar 
(look for the Plugin2 folder)