Swing applet in Java in java pgm

Swing applet in Java

import javax.swing.*;

import java.applet.*;

import java.awt.*;

import java.awt.event.*;

public class SApplet extends Applet implements ActionListener

{

   TextField input,output;

   Label label1,label2;

   Button b1;

   JLabel lbl;

   int num, sum = 0;

   public void init()

   {

      label1 = new Label("please enter number : ");

      add(label1);

      label1.setBackground(Color.yellow);

      label1.setForeground(Color.magenta);

      input = new TextField(5);

      add(input);

      label2 = new Label("Sum : ");

      add(label2);

      label2.setBackground(Color.yellow);

      label2.setForeground(Color.magenta);

      output = new TextField(20);

      add(output);

      b1 = new Button("Add");

      add(b1);

      b1.addActionListener(this);

      lbl = new JLabel("Swing Applet Example. ");

      add(lbl);

      setBackground(Color.yellow);

   }

   public void actionPerformed(ActionEvent ae)

   {

      try

      {

         num = Integer.parseInt(input.getText());

         sum = sum+num;

         input.setText("");

         output.setText(Integer.toString(sum));

         lbl.setForeground(Color.blue);

         lbl.setText("Output of the second Text Box : "

         + output.getText());

      }

      catch(NumberFormatException e)

      {

         lbl.setForeground(Color.red);

         lbl.setText("Invalid Entry!");

      }

   } 

}