private static void createAndShowGUI() {
        //Create and set up the window.
        FlowLayoutDemo frame = new FlowLayoutDemo("FlowLayoutDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        //Set up the content pane.
        frame.addComponentsToPane(frame.getContentPane());
        //Display the window.
        frame.pack();
        frame.setVisible(true);
    }