When JIRA breaks for some reason, and users see output of 500page.jsp, the JIRA admin typically wants to know about this. JIRA ought to log (to a special log4j category) all the info displayed on the screen.

A nice way to do with is create a bean containing all diagnostic info, whose toString() prints a nicely formatted log. The bean could be instantiated in the JSP with <webwork:bean> and rendered.