Reported with NetBeans:
(http://netbeans.org/bugzilla/show_bug.cgi?id=214039)

Product Version: NetBeans IDE Dev (Build 201206110001)
Java: 1.7.0_05; Java HotSpot(TM) 64-Bit Server VM 23.1-b03
System: Mac OS X version 10.7.3 running on x86_64; UTF-8; en_US (nb)

I've two monitors - left main monitor and right side monitor.
I've ran IDE in side monitor, do some stuff in main monitor for a while (work with Chrome, Adium etc.) and when I focused IDE back, it stops responding, dock stops responding too, so I must kill it by force with by Activity Monitor.
Don't know if it's random or reproducible.

Java thread dump attached.