package ex05_09;import java.awt.*;import java.awt.event.*;import javax.swing.*;public class Frame1 extends JFrame {  JPanel contentPane;  JButton jButton1 = new JButton();  /**Construct the frame*/  public Frame1() {    enableEvents(AWTEvent.WINDOW_EVENT_MASK);    try {      jbInit();    }    catch(Exception e) {      e.printStackTrace();    }  }  /**Component initialization*/  private void jbInit() throws Exception  {    //setIconImage(Toolkit.getDefaultToolkit().createImage(Frame1.class.getResource("[Your Icon]")));    contentPane = (JPanel) this.getContentPane();    jButton1.setText("jButton1");    jButton1.setBounds(new Rectangle(33, 25, 79, 29));    jButton1.addActionListener(new java.awt.event.ActionListener() {      public void actionPerformed(ActionEvent e) {        jButton1_actionPerformed(e);      }    });    contentPane.setLayout(null);    this.setSize(new Dimension(400, 300));    this.setTitle("Frame Title");    contentPane.add(jButton1, null);  }  /**Overridden so we can exit when window is closed*/  protected void processWindowEvent(WindowEvent e) {    super.processWindowEvent(e);    if (e.getID() == WindowEvent.WINDOW_CLOSING) {      System.exit(0);    }  }  void jButton1_actionPerformed(ActionEvent e) {for (int x=0 ; x<5 ; x++)  {  for (int y=0 ; y<=x ; y++)    {      System.out.print(y);    }  System.out.println();  }  }}