We've a couple reports of crashes with cms in mustang when using netbeans. They are all crashes in vtable chunks which indicates a bad oop of some kind but they don't happen very often. From the err log it looks like the oop has been reclaimed since it appears to be on the CMS free list. We've got one core from solaris x86 for b78 that I'll attach later and I'm going to try to get a crash dump from the windows user seeing this problem with b81. I've attached the 2 hs_err logs we have. Included for one of the crashes is the output of -XX:+VerifyDuringGC which shows the missed oops.