Minecraft Server becomes unresponsive.

I hate to do this to you Mojang BUT

I am running the Pre Release 1 on my server, and it randomly becomes unresponsive. No Crash Report. The only way I can recover is to kill the java process.

We are currently running 47c with no issues, but anything after that had been unplayable, and the pre release 1 seemed to fix the lag issues, but introduced the crash. Minecraft doesn't produce a crash report/log to attach.

I know reports like this aren't entirely helpful, but figured I'd better report the issues I was encountering.