Swing Buttons with Action Listener

test.java

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

class MyFrame extends JFrame
{
	public MyFrame()
	{
		this.setTitle("Example Application");
		this.setSize(400,100);
		this.setDefaultCloseOperation(EXIT_ON_CLOSE);
		this.setLayout(new FlowLayout());
	}
}

class Clicker implements ActionListener
{
	public void actionPerformed(ActionEvent e)
	{
		String cmd = e.getActionCommand();
		if(cmd == "hi")
		{
			System.out.println("Hi !");
		}
		else if(cmd == "bye")
		{
			System.out.println("Bye !");
		}
	}
}

class MyApp
{
	public MyApp()
	{
		MyFrame myframe = new MyFrame();
		
		JButton hibutton = new JButton("Hi!");
		hibutton.setActionCommand("hi");
		hibutton.addActionListener(new Clicker());
		hibutton.setToolTipText("Prints Hi!");
		
		JButton byebutton = new JButton("Bye!");
		byebutton.setActionCommand("bye");
		byebutton.addActionListener(new Clicker());
		byebutton.setToolTipText("Prints Bye!");
		
		JLabel mylabel = new JLabel("Hello World!");
		
		myframe.add(mylabel);
		myframe.add(hibutton);
		myframe.add(byebutton);
		
		myframe.setVisible(true);
	}
}

public class test
{
	public static void main(String args[])
	{
		MyApp myapp = new MyApp();
	}
}