showMessageDialog and showInput Dialog windows do not appear

Hello,

I am using BlueJ to run the program below; it compiles fine but the input and output windows DO NOT show. Any ideas?

import javax.swing.JOptionPane; //or import javax.swing.*;

public class Comparison {

public static void main( String args[] )
{
String firstNumber;

String secondNumber;

String name;

String result;

int number1;

int number2;

firstNumber =
JOptionPane.showInputDialog ( " Enter the first integer " );
secondNumber =
JOptionPane.showInputDialog ( " Enter the second integer " );


number1 = Integer.parseInt ( firstNumber );

number2 = Integer.parseInt ( secondNumber );

result = "";

if ( number1== number2)
result = number1 + "==" + number2;

if ( number1!= number2)
result = number1 + "!=" + number2;

if ( number1 < number2)
result = result + "\n" + number1 + " < " + number2;

if ( number1 > number2)
result = result + "\n" + number1 + " > " + number2;

if ( number1 <= number2)
result = result + "\n" + number1 + " <= " + number2;

if ( number1 >= number2)
result = result + "\n" + number1 + " >= " + number2;

JOptionPane.showMessageDialog (

null, result , "Comparison Results",

JOptionPane.INFORMATION_MESSAGE );

System.exit ( 0 );
}
}

It works fine for me

Code:

---

import javax.swing.JOptionPane;

public class Comparison
{
        public static void main(final String args[])
        {
                String firstNumber;
                String secondNumber;
                String result;
                int number1;
                int number2;
                firstNumber = JOptionPane.showInputDialog(" Enter the first integer ");
                secondNumber = JOptionPane.showInputDialog(" Enter the second integer ");
                number1 = Integer.parseInt(firstNumber);
                number2 = Integer.parseInt(secondNumber);
                result = "";
                if (number1 == number2)
                        result = number1 + "==" + number2;
                else if (number1 != number2)
                        result = number1 + "!=" + number2;

                if (number1 < number2)
                        result = result + "\n" + number1 + " < " + number2;
                else if (number1 > number2)
                        result = result + "\n" + number1 + " > " + number2;

                if (number1 <= number2)
                        result = result + "\n" + number1 + " <= " + number2;

                if (number1 >= number2)
                        result = result + "\n" + number1 + " >= " + number2;

                JOptionPane.showMessageDialog(null, result, "Comparison Results", JOptionPane.INFORMATION_MESSAGE);
                System.exit(0);
        }
}

---