This is really useful when working on plugin development & making frequent changes to jsps/java files.
If you have Service builder as part of your plugin & you changed any of XXXLocalServiceImpl.java/XXXServiceImpl.java file(s) - after you re-run service builder, you may need to re-deploy/restart the server. Service builder re-run seems messes up context (with auto-reload)
I did used this setup long back though (5.2 EE sp3) BUT found this is very helpful
http://www.liferay.com/web/guest/community/wiki/-/wiki/Main/Fast+Development+of+Liferay+Plugins+with+Tomcat
Njoy fast dev..ing