Tic Tac Toe Applet

Here is a simple two-player Tic Tac Toe applet, just to get familiar with ActionListeners and basic GridView. Hopefully, the code below is well-commented and self-explanatory.

	import javax.swing.*;
	import java.awt.*;
	import java.awt.event.*;
	import java.applet.*;
	@SuppressWarnings("serial")
	public class TicTacToe extends Applet implements ActionListener{
	JButton button[][] = new JButton[3][3];
	boolean isZero = true; //first turn is always 0
	public void init(){
	setSize(500, 500);
	setLayout(new GridLayout(3,3));
	//initialize the Grid and add ActionListener to each Button
	for(int i = 0; i < 3; i++){
	for(int j = 0; j < 3; j++){
	button[i][j] = new JButton("");
	add(button[i][j]);
	button[i][j].addActionListener(this);
	}
	}
	}
	public void actionPerformed(ActionEvent event){
	for(int i = 0; i < 3; i++)
	for(int j = 0; j < 3; j++){
	if((event.getSource() == button[i][j])){
	if(isZero){
	button[i][j].setText("O");
	}
	else{
	button[i][j].setText("X");
	}
	button[i][j].removeActionListener(this); //you cannot click on one tile more than once
	isZero = !isZero;
	checkForWinners(); //check if any winner after each move
	}
	}
	}
	public void checkForWinners(){
	//3 horizontal lines
	for(int i = 0; i < 3; i++){
	if(button[i][0].getText().equals(button[i][1].getText())
	&& button[i][1].getText().equals(button[i][2].getText())
	&& !button[i][0].getText().equals("")){
	JOptionPane.showMessageDialog(null, button[i][0].getText() + " wins!");
	return;
	}
	}
	//3 vertical lines
	for(int i = 0; i < 3; i++){
	if(button[0][i].getText().equals(button[1][i].getText())
	&& button[0][i].getText().equals(button[2][i].getText())
	&& !button[0][i].getText().equals("")){
	JOptionPane.showMessageDialog(null, button[0][i].getText() + " wins!");
	return;
	}
	}
	//top to bottom (rightwards) diagonal
	if(button[0][0].getText().equals(button[1][1].getText())
	&& button[1][1].getText().equals(button[2][2].getText())
	&& !button[0][0].getText().equals("")){
	JOptionPane.showMessageDialog(null, button[0][0].getText() + " wins!");
	return;
	}
	//bottom to top (leftwards) diagonal
	if(button[0][2].getText().equals(button[1][1].getText())
	&& button[1][1].getText().equals(button[2][0].getText())
	&& !button[2][0].getText().equals("")){
	JOptionPane.showMessageDialog(null, button[2][0].getText() + " wins!");
	return;
	}
	}
	}

view raw Tic Tac Toe Applet hosted with ❤ by GitHub

Here are some snaps of the output :