How to Add Button in java applet?

    import java.applet.*;
import java.awt.*;
import java.awt.event.*;

/*


*/

public class nineA extends Applet
{
	Button a=new Button("Click to change the color");

	boolean flag=true;
	
	public void init()
	{
		add(a);
	}
	
	public void paint(Graphics g)
	{
		if(flag)
			setBackground(Color.blue);
		else
			setBackground(Color.red);
	}

	public boolean action(Event e,Object o)
	{
		if(e.target==a)
		{
			flag =! flag;
			repaint();

			return true;
		}
			return false;
	}
}