Common Portlet Issues
Interactive debugging
Interactive debugging with the Sysdeo Tomcat Plugin
Many uPortal developers use the SysDeo Tomcat Launcher plugin for Eclipse. This plugin is available at http://www.eclipsetotale.com/tomcatPlugin.html.
It can start/restart/stop Tomcat from buttons in Eclipse, automatically configures debugging and does its best to do hot-deploy (though some turn this off as they find it causes more problems than it solves). uPortal developers have been using it since the beginnings of using Eclipse with uPortal and are still using it with Eclipse 3.3.
Interactive debugging with Eclipse WTP
Other uPortal developers have had success using Eclipse WTP to launch Tomcat (which autoconfigures debugging if you start in the mode) but unchecking the options to deploy projects, and using Ant or Maven to deploy. The disadvantage is you lose the hot-code deploy you would get in a full Eclipse WTP integrated process, but it is slightly simpler than manually configuring the remote debugger connection. Having the tomcat console appear in Eclipse so you can click on hyperlinks in stack traces is a nice plus too.