How Change Background Color Using Checkbox In Java

package abcde;
import java.applet.*;
import java.awt.Checkbox;
import java.awt.CheckboxGroup;
import java.awt.Color;
import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.Label;
import java.awt.event.*;

import javax.swing.*;

public class rgbcolor extends Applet implements  ItemListener
{
Checkbox a1,a2,a3;
public void init()
{
a1=new Checkbox("RED");
a2=new Checkbox("GREEN");
a3=new Checkbox("BLUE");
a1.addItemListener((ItemListener)this);
a2.addItemListener((ItemListener)this);
a3.addItemListener((ItemListener)this);
add(a1);
add(a2);
add(a3);
}
public void itemStateChanged(ItemEvent IE)
{
if("RED".equals(IE.getItem()))
{
this.setBackground(Color.red);
}
else if ("GREEN".equals(IE.getItem()))
{
this.setBackground(Color.green);
}
else
{
this.setBackground(Color.blue);
}

}
}