code: public JFrame getMainWindow()
      {
          if (mainWindow == null)
          {
              mainWindow = new JFrame();
              mainWindow.setTitle("Swing Browser");
              mainWindow.setVisible(true);
              mainWindow.setBounds(new Rectangle(0, 0, 583, 251));
              mainWindow.setContentPane(getMainPanel());
              mainWindow.addWindowListener(new java.awt.event.WindowAdapter()
              {
                  public void windowClosing(java.awt.event.WindowEvent e)
                  {
                      mainWindow.setVisible(false);
                      System.exit(0);
                  }
              });
          }
          return mainWindow;
      }
docs: This method initializes jFrame
  
  @return javax.swing.JFrame