Java GUI

import javax.swing.JOptionPane;
class addGUI{
public static void main(String args[]){
String n1 = JOptionPane.showInputDialog("Enter number 1:");
String n2 = JOptionPane.showInputDialog("Enter number 2:");

int num1 = Integer.parseInt(n1);
int num2 = Integer.parseInt(n2);

int total;
total = num1 + num2;

JOptionPane.showMessageDialog(null, "Total = "+ total);
}
}