I need to do something in the jboss server periodically.
I know user can't create thread in the j2ee server, then how can i do that?
I can run another process, which will notify a message-driven bean in jboss periodically, then the bean will do something.
is that the only solution?
You can use the scheduler but you might find that more complex than using an external cron signal. See http://www.madplanet.com/jboss-docu-wiki/Wiki.jsp?page=40.Utilities.Scheduler for some basic information on how it works. The instructions should be applicable to a 3.2.x installation.