code: private static void createAndShowGUI() {
  
      // Create and set up the window.
      JFrame frame = new JFrame("XChart Demo");
      frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
  
      // Add content to the window.
      frame.add(new XChartDemo());
  
      // Display the window.
      frame.pack();
      frame.setVisible(true);
    }
docs: Create the GUI and show it. For thread safety, this method should be invoked from the event
  dispatch thread.