1. By default, iPlanet Web Server uses a JRE to run, but (remote) debugging requires a full JDK. Now, if the server is using the JRE, you need to switch it to using the JDK (1.3.0+) before you can do remote debugging. Here is how:
Switch to the Web Server Administration Server, select the Global Settings tab, and use the Configure JRE/JDK Paths page. On the Configure JRE/JDK Paths page, supply values for only the "JDK Path" once you have selected the JDK radio button:
JDK Path : Enter the path for the JDK. This is the directory where you installed the JDK. (C:\jdk1.3.1).
JDK Runtime Libpath : leave blank, unless required
JDK Runtime Classpath : leave blank, unless required
2. Also, make sure that the server is running in single-process mode. Single-process mode is the default, but you can check in the file magnus.conf to make sure that the MaxProcs parameter is not set to a value greater than 1. If you do not see a setting for MaxProcs in magnus.conf, the default value of 1 is enabled for it.
3. Make sure that the following parameters exist in your jvm12.conf (make a backup before making changes):
5. Apply the changes to the server and then restart the server.
6. Make sure that your source code and deployed application are in sync.
7. In the Project Properties | Runtime Properties | Debug | check, "Enable remote debugging" | Attach | OK
8. Add a breakpoint in your servlet code
9. Project | Debug (it should just sit there and do nothing)
10. Finally, open IE and hit the URI for your servlet deployed to iPlanet. If you return to JBuilder, you should see the line of execution stopped at the breakpoint in your servlet.