This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
There are some ways to configure the criteria the server will use to perform passivation (such as the idle timeout value). Sorry, I don't remember how to do that in JBoss. Going off on a tangent, any chance you could use stateless session beans? Stateful ones are not that common these days due to numerous performance and maintenance issues.