Layout Demo program in Java

 /*  
   Title : Program for demonstrating Layouts in Java  
   Author: Yasar Shaikh  
 */  
 import java.awt.*;  
 import java.awt.event.*;  
 import java.applet.*;  
 public class LayoutDemo extends Frame implements ActionListener  
 {  
      Button b1,b2,b3,b4,b5,b6;  
      Button l1,l2,l3;  
      CheckboxGroup cbg;  
      Checkbox c1,c3,c2;  
      Panel p1,p2,main;  
      LayoutDemo l;  
      public LayoutDemo()  
      {  
           p1=new Panel();  
           p2=new Panel();  
           main=new Panel();  
           l=this;  
           p1.setLayout(new FlowLayout());  
           p2.setLayout(new GridLayout());  
           cbg=new CheckboxGroup();  
           c1=new Checkbox("Left",cbg,false);  
           c2=new Checkbox("Center",cbg,false);  
           c3=new Checkbox("Right",cbg,false);  
           l1=new Button("Flow");  
           l2=new Button("Grid");  
           l3=new Button("Border");  
           b1=new Button("Button 1");  
           b2=new Button("Button 2");  
           b3=new Button("Button 3");  
           b4=new Button("Button 4");  
           b5=new Button("Button 5");  
           b6=new Button("Button 6");  
           p1.add(b1);          p1.add(b2);  
           p1.add(b3);          p1.add(b4);  
           p1.add(b5);          p1.add(b6);  
           p1.add(c1);p1.add(c2);p1.add(c3);  
           p2.add(l1);p2.add(l2);p2.add(l3);  
           l1.addActionListener(this);  
           l2.addActionListener(this);  
           l3.addActionListener(this);  
           main.setLayout(new BorderLayout());  
           main.add(p1,BorderLayout.NORTH);  
           main.add(p2,BorderLayout.SOUTH);  
           add(main);  
      }  
      public void actionPerformed(ActionEvent ae)  
      {  
           if(ae.getSource()==l2)  
           {  
                l.setSize(700,700);  
                repaint();  
                p1.setLayout(new GridLayout(3,3));  
           }  
           else if(ae.getSource()==l3)  
           {  
                l.setSize(800,800);  
                repaint();  
                main.add(p1,BorderLayout.WEST);  
           }  
           else  
           {  
                l.setSize(600,600);  
                repaint();  
                p1.setLayout(new FlowLayout());  
           }  
      }  
      public static void main(String ar[])  
      {  
           LayoutDemo l=new LayoutDemo();  
           l.setSize(600,600);  
           l.setVisible(true);  
      }  
 }  
 /*  
 PS: Save the above program with the name LayoutDemo.java (case-sensitive)  
     and then compile it with "javac LayoutDemo.java" command and execute  
     it with "java LayoutDemo" command in command prompt/terminal.   
 */