Have you followed the Fibonacci Tutorial? Section 10 includes information on how to startup JBoss AppServer from "within" Eclipse as a Debug Configuration. Once this configuration is setup, it launches JBoss AS with the output going to the Console in Eclipse. You build, package and deploy your application with the debug breakpoint enabled.
I'm assuming that you have gotten the little blue dot to show up in the left-side of the editor beside the line in the JSP that you wish to debug.
Then hit the browser with the right URL and Eclipse will flip into the Debug Perspective.
As additional info on this topic.
In the Debug dialog (Debug...), on the Source tab, I added a Java Project (Add..) and tied in my Struts project.
I can interactively turn on and off debugging by simple toggling the breakpoints in a Struts action class and hitting refresh in the browser.
(Note: the change to the Source tab, requires a restart of the app server to take effect). No saving, packaging and redeploying.
I used to use IBM RAD (WSAD renamed at 6.0) so this functions as I expect it to.
Yes debugging works fine with normal java classes (servlet, action classes) but does not work for jsp files. Whenever i double click on the break point column the add bookmark dialog appears.