Java GUI basic

import javax.swing.*;


class StockGUI {

    public static void main(String[] args) {
        String fn = JOptionPane.showInputDialog("First number");
        String sn = JOptionPane.showInputDialog("Second number");

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

        JOptionPane.showMessageDialog(null,"Equals " + (num1 + num2),"Add",JOptionPane.PLAIN_MESSAGE);
    }
}