That is, the ability to use and evaluate an expression that is the root path of a webapp.
Refer to http://groups.google.com/group/ebean/browse_thread/thread/73f098ff6546c4c0
In the web.xml you can register Ebeans ServletContextListener.
<web-app> <listener> <listener-class> com.avaje.ebeaninternal.server.core.ServletContextListener </listener-class> </listener> ...
If you register this ServletContextListener then it will set a variable called "servlet.realpath" to be the absolute path of the webapp.