I believe you would need to be logged into the server as the same user who is running JBoss and possibly the JBoss would need to be running as an application and not a service. It's likely the process is triggering (unless you have an exception in your server.log), but you just can't see it. As you are firing up an explorer window it probably won't have an entry in Task Manager either. I'd try with an obvious process you can be sure isn't running first like notepad.exe and check whether it appears in task manager on the server after the code runs.
It seems strange to be firing up GUI-based applications from a server side process except in the rarest of circumstances. Did you intend for the explorer window to run for the user who is doing the process? If so, I believe that's impossible as Workspace is a Flash application, and Flash very sensibly does not allow execution of code on client machines.