PROGRAMACION DE UNA CLASE "HOLA MUNDO"

import javax.swing.JFrame;
import javax.swing.JOptionPane;

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

public class hola extends JFrame{

public static void main (String [] args){
JOptionPane.showMessageDialog (null,"¡Hola Mundo!");
JOptionPane.showMessageDialog(null,"Adios");
System.exit(0);
}

}