Ok this is just my guess since I've been kind of desparate lately...

I'm running the latest Hibernate. I only have 1 application that uses Hibernate on my web server... and from time to time that application freezes. Doing a server restart doesn't work in that case for some reason, so I'm forced to kill -9 the java proccess.

Lately though doing kill -9 didn't help. Java just went zombie on me and I had to reboot the computer.

Now the reason I suspect it could be Hibernate is because I just wrote another non-web application that used Hibernate... and guess what! Java proccess that's running it goes zombie on me!

Any idea what might be causing it? People were tellling me that it's most likely some IO error that causes it, probably has to do with database and therefore hibernate...

Any ideas?

i never ever had such a problem with hibernate and i can't imagine that hibernate is the problem. if it has to do with the database then it could be the connectionpool, jdbc driver, database or the constellation of them so i would sugest to test it with another connectionpool or jdbcdriver.

It's been at least 5 years since I've seen anything like that and it was definitely an issue with the Microsoft JDBC driver.

Do not forget to close session factory.

BTW try kill -3 if it doe's not help, jvm will dump all threads to stdout, it will hep to find running non deamon thread (jvm exits when the only threads running are all daemon threads).

Hmm closing the session factory? Hibernate in action failed to note that...

And kill -3 doesn't work when the proccess is a zombie.

nonkillable processes mean that exists hardware (or software driver for any hardware) bugs
(probably).I don't think that is java or hibernate problem
Can you try same things with another computer ?

Hibernate doe's not start any threads, db pool or cache may need "factory.close()", it signals to stop all user threads and to release resources. It doe's not help to avoid deadlock, it just helps to restart server. kill -3 must help to debug deadlock on most systems (I am sure it works on linux), but try to start server as application if this is solaris, it ignores this signal for deamons (if process is the real "zombie" then it must ignore kill -9 too).