import javax.swing.JFrame; import javax.swing.JButton; public class FirstSwingDemo { public static final int WIDTH = 300; public static final int HEIGHT = 200; public static void main(String[] args) { JFrame firstWindow = new JFrame(); firstWindow.setSize(WIDTH, HEIGHT); firstWindow.setTitle("First Window Program!"); firstWindow.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE); JButton endButton = new JButton("Click to end program."); EndingListener buttonEar = new EndingListener(); endButton.addActionListener(buttonEar); firstWindow.add(endButton); firstWindow.setVisible(true); } }