Java applet básico

import java.awt.GridLayout;
import java.awt.Button;
import java.awt.Color;
import java.applet.Applet;
import javax.swing.*;
import java.awt.FlowLayout;
import java.awt.Button;
import java.awt.Color;
import java.awt.event.*;
import java.awt.*;
import javax.swing.*;

public class memoria extends Applet 
{ 
	
        JButton bsair = new JButton("Sair");
	JButton brecomecar = new JButton("Recomecar");
	JButton bbaralhar = new JButton("Baralhar");
	JButton bresolver = new JButton("Resolver");
	FlowLayout fl = new FlowLayout();
  
	JButton b1 = new JButton("1"); JButton b2 = new JButton("2");
	JButton b3 = new JButton("3"); JButton b4 = new JButton("4");
	JButton b5 = new JButton("5"); JButton b6 = new JButton("6");
	JButton b7 = new JButton("7"); JButton b8 = new JButton("8");
	JButton b9 = new JButton("9"); JButton b10 = new JButton("10");
	JButton b11 = new JButton("11"); JButton b12 = new JButton("12");
	JButton b13 = new JButton("13"); JButton b14 = new JButton("14");
	JButton b15 = new JButton("15"); JButton b16 = new JButton("16");
	GridLayout gl = new GridLayout(6, 6, 10, 10);
	
	public class MyJPanel extends JPanel
	{
	    public int x = 100;		//CountDown from 100	
	    public int delay = 1000; 	//milliseconds

	    MyJPanel()
	    {
			 ActionListener counter = new ActionListener() 
			 {
				public void actionPerformed(ActionEvent evt) 
				{ 
					  repaint();
					  x--;
				}
			};
			new Timer(delay, counter).start();
	    }

	    public void paintComponent(Graphics g)
	    {
			super.paintComponent(g);
			g.drawString(""+x,100,100);
	    }
	}

	public void init() 
	{
		setBackground(Color.blue);
		setLayout(gl);
		add(b1); add(b2); add(b3); add(b4); add(b5); add(b6); add(b7); add(b8);
		add(b9); add(b10); add(b11); add(b12); add(b13); add(b14); add(b15); add(b16);
		add(bsair); add(brecomecar); add(bbaralhar); add(bresolver);
	}
	
	public class JPanelDrawing extends JFrame
	{ 
		JPanelDrawing()
		{
			Container container = getContentPane();
			MyJPanel panel = new MyJPanel();
			container.add(panel);	  
			setDefaultCloseOperation(EXIT_ON_CLOSE);
			setSize(150,80);
			setTitle("JPanel Countdown");
			setVisible(true);
		} 
	} 
	public void actionPerformed(ActionEvent event) 
	{	
		JButton clicked = (JButton)event.getSource();
		if(clicked == bsair)
		{
			System.exit(0); //sai do jogo
		}

		else if(clicked == brecomecar)
		{
		}
		
		else if(clicked == bbaralhar)
		{
		}
		
		else if(clicked == bresolver)
		{
		}
	}	
}