This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
What is this session's age ? Can you post some code ? Why dont you write an object that implements the session binding listener so you know when it gets unbound ? Just in case the session is being invalidated without you calling invalidate()