Version 5.0 of the NetBeans IDE has great support for version 8 of the Sun Java System Application Server (SJS AS). But what if you are using version 7 of SJS AS? The IDE can still do plenty for you, including debugging. For the test shown below, I used the 2004Q2UR4 release of SJS AS 7.1.

The first step is to start SJS AS in debug mode. This is easy enough to do. From the admin console, go to the server settings page and check the Start in Debug Mode option.

Then just stop and restart the server. That will start the server's JVM with the following flags (these are the default values):

  
    -Xdebug
    -Xrunjdwp:transport=dt_socket,
              server=y,
              suspend=n,
              address=2646 
    -Xnoagent 
    -Djava.compiler=NONE      
  

The second step is to create a project within the NetBeans IDE. This will give the IDE a way to understand where your source code is, the required classpath, etc. For this example I used one of the sample projects that is included with SJS AS 7.

1. Choose File > New Project
2. Under Categories choose General and then under Projects choose Java Project with Existing Ant Script and then click Next. Note: if you do not have an Ant build script then you can instead choose Java Project with Existing Source.
3. Set the Location field to the folder that contains your project. Note that in the example shown below, the IDE found the build.xml that was in that folder.
4. Set the Project Name to whatever value you want. Then click the Next button.
5. Click the Next button again to advance past the Build and Run actions.
6. Specify the source root folders for your application and then click Next.
7. Specify the classpath for your application and then click Finish.

The third step is to attach the IDE to the server's JVM. Choose Run > Attach Debugger. In the Attach dialog verify that Socket Attach is selected and that the Port number is 2646. Then click OK.

After the IDE attaches to the JVM you are ready to debug. You can set breakpoints by opening the source files in the project and using Run > New Breakpoint.