Tomcat is crashing. When it crashes, we have no access to our mailboxes via IMAP etc. So its a fairly important process!

There is out-of-memory logs in the catalina logs -- but why?

Data points:

- Tomcat is started up with 607MB of memory (default setting).
- Machine has 1.5GB memory (Linux Fedora4)
- There are NO users on the system when it decides to crash.
- We have set the max message size to be 10MB
- Upgraded to the latest/greatest Zimbra release (made no difference)
- Total mailboxes on the system is a whopping 20!
- Trouble free system for over a year except for the last week

What can we do if someone tries to push a bigger email to the system? There is obviously an email in there somewhere that is causing the system to choke. Why did it get in there in the first place though? How do we find out which email is causing the fault?

Please advise -- as this is making what was a beautifully running system, completely unuseable and a nightmare to manage.