Simple Push button and handle action event example in java!

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// Demostrate a push button and handle action events.

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

class ButtonDemo implements ActionListener {
 JLabel jlab;

 ButtonDemo() {
  // Create a new JFrame container. 
  JFrame jfrm = new JFrame("A Button Example");

  // Specify FlowLayout for the layout manager.
  jfrm.setLayout(new FlowLayout());

  // Give the frame an initial size.
  jfrm.setSize(220, 90);

  // Terminate the program when the user closes the application.
  jfrm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

  // Make two buttons.
  JButton jbtnUp = new JButton("Up");
  JButton jbtnDown = new JButton("Down");

  // Add action listeners.
  jbtnUp.addActionListener(this);
  jbtnDown.addActionListener(this);

  // Add the buttons to the content pane.
  jfrm.add(jbtnUp);
  jfrm.add(jbtnDown);

  // Create a Label.
  jlab = new JLabel("Press a button.");
  
  // Add the label to the frame.
  jfrm.add(jlab);

  // Display the frame.
  jfrm.setVisible(true);
 }

 // Handle button events.
 public void actionPerformed(ActionEvent ae) {
  if(ae.getActionCommand().equals("Up"))
   jlab.setText("You pressed Up.");
  else
   jlab.setText("You pressed down.");
 }

 public static void main(String args[]) {
  // Create the frame on the event dispatching thread.
  SwingUtilities.invokeLater(new Runnable() {
   public void run() {
    new ButtonDemo();
   }
  });
 }
}