Input JOptionPane

[nic21]

Dear everyone, anyone can help me to validate this program which only accept number? what i mean is when i type in alphabet it will prompt a message ask us to key in numbers only... anyone could help please... :confused:

import javax.swing.*;

public class additiontutor
{
 public static void main(String args[])
 {
  int number1 = (int)(System.currentTimeMillis() % 10);
  int number2 = (int)(System.currentTimeMillis() * 7 % 10);

  String answerString = JOptionPane.showInputDialog
    ("What is " + number1 + " + " + number2 + "?");

  int answer = Integer.parseInt(answerString);
  
  JOptionPane.showMessageDialog(null,
    number1 + " + " + number2 + " = " + answer + " is " +
    (number1 + number2 == answer));
 
 }
}

[camickr]

Cross post: Swing - Input JOptionepane