plz tell me

Here is a java swing code that counts the number of times the button clicked.

import javax.swing.*;
import java.awt.event.*;

public class CountButtonClicks extends JFrame{
  public static void main(String[] args){
    new CountButtonClicks();
 }
   JButton button1 = new JButton("Click Me!");
    int clickCount = 0;
    public CountButtonClicks(){
    this.setSize(275, 100);
    JPanel panel1 = new JPanel();

    button1.addActionListener(new ActionListener(){
          public void actionPerformed(ActionEvent e) {
        clickCount++;
          button1.setText("clicked " + clickCount + " times!");
    }
    });
    panel1.add(button1);
    this.add(panel1);
    this.setVisible(true);
  }
}