public void createTopMenu(String menuName) {
JFrame frame = new JFrame();
frame.setTitle("Create a new menu");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(new Dimension(200,200));
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
Dimension frameSize = frame.getSize();
frame.setLocation((screenSize.width - frameSize.width) / 2,(screenSize.height - frameSize.height) /2 );
//Create and set up the content pane.
TopMenu contentPane = new TopMenu(frame, menuName);
contentPane.setOpaque(true); //content panes must be opaque
frame.setContentPane(contentPane);
//Display the window.
frame.pack();
frame.setVisible(true);
}