Implementar um jogo

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
   public class TicTacToe extends JApplet {
private JTextArea display;
private JPanel boardPanel, panel2;
private Board board;
private char mark;
public void init() {
display = new JTextArea( 4, 30 );
display.setEditable( false );
getContentPane().add( new JScrollPane( display ), borderLayout.SOUTH );
boardPanel = new JPanel();
GridLayout layout = new GridLayout( 3, 3);
boardPanel.setLayout ( layout );
for ( int row = 0; row < 3 ; row++ ) {
for ( int col = 0; col < 3; col++ ) {
board = new Board();
board.addMouseListener( new BoardListener( this, board ) );
boardPanel.add( board );
}
}
panel2 = new JPanel();
panel2.add( boardPanel, BorderLayout.CENTER );
getContentPane().add( panel2, BorderLayout.CENTER );
mark = 'X';
display.append("Jogador " + mark + " jogando...
");
}
public void boardClick( Board b ) {
b.setMark( mark );
b.repaint();
mark = ( mark == 'X' ? 'O' : 'X' );
display.append("Jogador " + mark + " jogando...
");
}
}

class Board extends JPanel {
private char mark;
public Board() {
mark = ' ';
setSize ( 30, 30 );
setVisible(true);
}
public Dimension getPreferredSize() {
return ( new Dimension( 30, 30 ) );
}
public Dimension getMinimumSize() {
return ( getPreferredSize() );
}
public void setMark( char c ) {
mark = c;
}
public void paintComponent( Graphics g ) {
super.paintComponent( g );
g.drawRect( 0, 0, 29, 29 );
g.drawString( String.valueOf( mark ), 11, 20 );
}
}
class BoardListener extends MouseAdapter {
private TicTacToe applet;
private Board board;
public BoardListener( TicTacToe t, Board b ) {
applet = t;
board = b;
}
public void mouseReleased( MouseEvent e ) {
applet.boardClick( board );
}
}