Remington Li contributed this advice in the servlets-jsp newsgroup, 3/11/02.

[Note that the setting below is wrapped for easier reading. If you copy it into the JRun Management Console, be sure to unwrap it and make sure that it is complete. Also note that the snippet beginning at "-classic ..." and ending with "..., suspend=n" may be added to the java command-line for starting Weblogic 6.x to enable remote debugging. And finally, the on-line help in JBuilder has a help index "remote debugging" which will provide more details on what each parameter means.]

In JRun Management Console: Java Settings -> Java Arguments -> Add:
-classic -Xdebug -Xnoagent -Djava.compiler=NONE -Xrunjdwp:transport=dt_socket,server=y,address=5000,suspend=n

In JBuilder: Project -> Project Properties -> Debug -> Enable Remote Debugging -> Attach

In JBuilder: Project -> Project Properties -> Paths -> Source -> Add -> add the following path: %JRUN_WEB_APP_ROOT_DIRECTORY/WEB-INF/jsp