0416 --- Demo+Yes!

import java.awt.*;
import java.awt.event.*;

public class ActionEventDemo implements ActionListener {
    public static void main(String[] args) {
        new ActionEventDemo();
    }
   
    public ActionEventDemo() {
        Frame frame = new Frame("AWTDemo");
        frame.addWindowListener(new AdapterDemo());
        frame.setLayout(new FlowLayout());
       
        Button button = new Button("demo");
        button.setActionCommand("d1");
        button.addActionListener(this);
       
        frame.add(button);
        frame.pack();
        frame.setVisible(true);
    }
   
    public void actionPerformed(ActionEvent e) {
        String cmd = e.getActionCommand();
        if (cmd == "d1") {
            System.out.println("Yes....");
        }
    }
}

class AdapterDemo extends WindowAdapter {
    public void windowClosing(WindowEvent e) {
        System.exit(0);
    }
}