Data Validation

I am really new to programming so take it easy on me :)

Here is the code. Basically what I want it to do is whenever the user
enters in 1 2 or 3 to say good job. When the user enters 4 to quit
and anything else display an error message. This code works fine as
long as the user enters in a int if anything else is entered it
crashes. How can i fix this? Thanks

   import javax.swing.*;
    public class Input123
   {
       public static void main(String[] args)
      {
         String input;
         int selection = 0;
         while (selection != 4) {
            input = JOptionPane.showInputDialog(null,"Enter in either
1, 2, 3, or 4 to quit");
            selection = Integer.parseInt(input);
            if(selection == 1 || selection == 2 || selection == 3) {
               JOptionPane.showMessageDialog(null,"Good Job");
            }
            else if(selection == 4){
               System.exit(0);
            }
            else {
               JOptionPane.showMessageDialog(null,"You have entered an
invalid character, Please try again.");
            }

         }

         System.exit(0);
      }
   }