We have an application with a JSP/Servlet frontend running on a JBoss 3.0.4-tomcat-4.0.6 server. What we would like to do is have serialized sessions written on disk uppon undeployment/deployment. The reason for this is to be able to do on line upgrades/patches of the application without the users being logged out. JBoss 2.x had this behaviour. Is it possible to get in JBoss 3.x?