J-Link + Swing GUI

I've created a J-Link application, which has a swing GUI. On click of a UI command button, I'm creating a part files (simulating File--> New Part). The same thing when wanted to simulate through a swing GUI in synchronous mode, the GUI gets created, but when I push the button in the GUI, the GUI hangs. Can any one help me in making the swing GUI work with PROE?

class MenuButtonListener extends DefaultUICommandActionListener {          publicvoid OnCommand() {                    try{                                   //This works                                   Session curSession = pfcGlobal.GetProESession();                                   Model tryModel = curSession.CreatePart("Testing");                                 tryModel.Display();                                    //This doesn't work                                   //How to make it work                                        csProe.StepToProeGui.createAndShowGUI();                      }catch (Exception x) {                              STEP_TO_PROE.printMsg("something wrong: " + x);                              x.printStackTrace();                              System.out.println("------------------------------------");                    }          }}