Event handling -Radio button

Program to change background color of frame  according to radio button.

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

/*

<applet code="pst19.java" width=100 height=200>

</applet>

*/

public class pst19 extends JApplet implements ActionListener

{

       Container contentPane=getContentPane();

      

       public void init()

       {

             

              contentPane.setLayout(new FlowLayout());

      

              JTextField jtf=new JTextField(17);

              contentPane.add(jtf);

             

              JRadioButton rb=new JRadioButton("Red");

              rb.addActionListener(this);

              contentPane.add(rb);

              JRadioButton rb1=new JRadioButton("Yellow");

              rb1.addActionListener(this);

              contentPane.add(rb1);

              JRadioButton rb2=new JRadioButton("Blue");

              rb2.addActionListener(this);

              contentPane.add(rb2);

      

              ButtonGroup bg=new ButtonGroup();

              bg.add(rb);

              bg.add(rb1);

              bg.add(rb2);

       }

       public void actionPerformed(ActionEvent ae)

       {

              String str;

              str=ae.getActionCommand();

      

              if(str=="Red")

              {

             

              contentPane.setBackground(Color.red);

              showStatus(str);

              }

                    

              else if(str=="Yellow")

              {

             

              contentPane.setBackground(Color.yellow);

              showStatus(str);

              }

             

              else if(str=="Blue")

              contentPane.setBackground(Color.blue);

       showStatus(str);

             

             

       }

}