do .. while

import javax.swing.*;

public class InputDoWhile
{
    static final int TRY = 3;
    public static void main(String[] args)
    {
        String inputString;
        String outputString;
        boolean isGood = false;
        int counter = 0;

        //do while
        do
        {
            counter++;
            inputString = JOptionPane.showInputDialog("Enter a four digit code: ");
            if ( inputString.length() == 4)
            {
                isGood = true;
            }

        } while (counter < TRY && !(isGood));//end do while


        if (isGood)
        {
            outputString = "Welcome your code is " + inputString + "\nwhich is 4 characters long";
            JOptionPane.showMessageDialog(null,outputString, "Correct",JOptionPane.INFORMATION_MESSAGE);
        } else
        {
            outputString = "Do not pass Go! " + inputString + " is not 4 letters " + "\nIt is, in fact, " + inputString.length();
            JOptionPane.showMessageDialog(null,outputString, "Idiot",JOptionPane.WARNING_MESSAGE);
        }
    }
}//class