Event can't excut.

Question

Hi all :
this my code I want to display a Frame then clink a Button
,the Event will change the name of File but the code can't run
i tried to many way but the same , Please help me .
thx
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.sql.*;
import java.util.*;
import javax.swing.*;
public class mainClass//Type your name of class
public static void main(String args[])
JFrame f = new JFrame();
Container contentPane = f.getContentPane();
contentPane.setLayout(new GridLayout(2,1));
JLabel l = new JLabel(new ImageIcon("ERR7.GIF"));
JButton b = new JButton(new ImageIcon("check.GIF"));
contentPane.add(l);
contentPane.add(b);
f.pack();
f.show();
f.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
public void addWindowListener(ActionEvent e)
File f1 = new File("1.txt");
if (f1.exists())
{System.out.print("ok");
// f1.renameTo("2.txt");
}

Answer 1

then the button be clink 1.txtx change to 2.txt
public void addWindowListener(ActionEvent e)
File f1 = new File("1.txt");
if (f1.exists())
{System.out.print("ok");
f1.renameTo("2.txt");
}