IllegalStateException in Sessions

[savas karabuz]

Hi,

We have a web application deployed on an iPlanet web server v4.1. Sometimes we get IllegalStateExceptions at the method call com.netscape.server.http.session.SimpleSession.getId(). In order to track the issue, we have added println statements to see whether a timeout occurred or not. Following is what we saw for the latest exception :

Current Time : Thu Jun 17 13:16:35 EEST 2004
Session Creation Time : Thu Jun 17 13:16:28 EEST 2004
Session Last Accessed Time : Thu Jun 17 13:16:35 EEST 2004
Session Maximum Inactive Interval Setting : 43200000

So, we deduce that the reason was not a session timeout. Is there any way for a session to cause those IllegalStateExceptions other than timeout and deliberate usage of

session.invalidate()

calls in the application?

Any bit of help is appreciated.

Thanks in advance...