Java ActionEvent get event source

import java.awt.FlowLayout;

import javax.swing.JButton;
import javax.swing.JFrame;

public class Main extends JFrame {
  public Main() {
    super("JButton");

    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setLayout(new FlowLayout());

    /*from  w  w  w .  j  a v a 2  s  .  c  om*/
    JButton bn = new JButton("Close");
    bn.addActionListener(e->{
      System.out.println(e.getSource() == bn);
    });

    getContentPane().add(bn);
  }

  public static void main(String[] args) {
    Main frame = new Main();
    frame.pack();
    frame.setVisible(true);
  }
}

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class Main {
  public static void main(String[] args) {
    JPanel panel = new JPanel();

    JButton close = new JButton("Close");
    close.addActionListener(new ButtonListener());

    JButton open = new JButton("Open");
    open.addActionListener(new ButtonListener());

    JButton find = new JButton("Find");
    find.addActionListener(new ButtonListener());

    JButton save = new JButton("Save");
    save.addActionListener(new ButtonListener());

    panel.add(close);/* w  ww.  ja  va 2s.c  om*/
    panel.add(open);
    panel.add(find);
    panel.add(save);
    JFrame f = new JFrame();
    f.add(panel);
    f.setSize(400, 300);
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.setVisible(true);
  }
}

class ButtonListener implements ActionListener {
  public void actionPerformed(ActionEvent e) {
    JButton o = (JButton) e.getSource();
    String label = o.getText();
    System.out.println(label + " button clicked");
  }
}