Java Programming Tutorial - 50 - Graphical User Interface...

import javax.swing.JOptionPane;

class apples {
   public static void main(String[] args){

      String fn = JOptionPane.showInputDialog("Enter first number");
      String sn = JOptionPane.showInputDialog("Enter second number");

      int num1 = Integer.parseInt(fn);
      int num2 = Integer.parseInt(sn);
      int sum = num1 + num2;

      JOptionPane.showMessageDialog(null, "The answer is " + sum, "the title", JOptionPane.PLAIN_MESSAGE);

   }
}