Tomcat Rolling Updates?

I need to be able to do rolling updates of some apps on a tomcat server. Unfortunately, this is a somewhat constrained environment. So, running a second instance of tomcat and front-ending them both with apache seems a little daunting. Does anyone know if there is a mechanism to rename a running app in tomcat and have it start to receive those requests without reloading the application? Does anyone else have a best practice for this type of thing??

Thanx