Example Program with a Button

Here is an example program that adds a button to a frame.

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

class ButtonFrame extends JFrame
{
  JButton bChange ; // reference to the button object

  // constructor for ButtonFrame
  ButtonFrame() 
  {
    // construct a Button
    bChange = new JButton("Click Me!"); 

    // add the button to the JFrame
    getContentPane().add( bChange );      
    setDefaultCloseOperation( WindowConstants.EXIT_ON_CLOSE );   
  }
}

public class ButtonDemo
{
  public static void main ( String[] args )
  {
    ButtonFrame frm = new ButtonFrame();

    frm.setSize( 200, 150 );     
    frm.setVisible( true );   
  }
}

To construct a JButton object, use new. Then add the button to the frame's content pane. The content pane is a container that represents the main rectangle of the frame. To get a reference to the content pane, use the getContentPane() method of the frame. The add method of a content pane puts a JButton (or other component) into the frame.