Java netbean program crashes after entering informatin on dialog boxes

Question

I have been stuck for days, my program keeps crashing. Please help. I am trying to obtain a jOptionPane dialog box that displays the first and last name, the boxes show up, but then my system crashes.

package rarjavazonapp;

import javax.swing.JOptionPane;
import java.util.Scanner;


/**l
 *
 * @author Rita Dennis
 */
public class RarJavazonApp {

/**
 * @param args the command line arguments
 */
public static void main(String[] args) {
    // TODO code application logic here
    Scanner sc = new Scanner(System.in);

    //COLLECT INFORMATION USING JOPTIONPANE


    String firstName = Validator.getValidFirstName(JOptionPane.showInputDialog( "Enter First Name"));
    String last = Validator.getValidFirstName(JOptionPane.showInputDialog( "Enter Last Name"));
    String Street = Validator.getValidFirstName(JOptionPane.showInputDialog( "Enter Street"));
    String State = Validator.getValidFirstName(JOptionPane.showInputDialog( "Enter State"));
    String Zip = Validator.getValidFirstName(JOptionPane.showInputDialog("Enter Zip"));
    String Phone = Validator.getValidFirstName(JOptionPane.showInputDialog( "Enter Phone"));
    String Membership = Validator.getValidFirstName(JOptionPane.showInputDialog( "Enter Membership"));


    //Do the same for the other variables
    String lastName = "";
    String street = "";
    String city = "";
    String state = "";
    String zip = "";
    String phone = "";
    String membership = "";

    //CREATE A NEW CUSTOMER OBJECT (uncomment line below)
    Customer customer = new Customer(firstName, lastName, street, city, state, zip, phone, membership);


    //CREATE NEW ORDER OBJECT
    Order order = new Order();

    //SET ORDER CUSTOMER
    order.setOrderCustomer(customer);

    //LOOP TO COLLECT PRODUCTS SELECTED BY USER AND THEIR QUANTITIES
    do {
        //CREATE MENU OBJECT
        Menu menu = new Menu();

        //Get the items from the menu class, and load them into the
        //JOptionPane menu
        String menuItems[] = menu.getMenuDescriptions();

        int intCode = 0;
        intCode = JOptionPane.showOptionDialog(null, "Select an Option",
                "Menu Items", JOptionPane.YES_NO_CANCEL_OPTION,
                JOptionPane.QUESTION_MESSAGE, null, menuItems, menuItems[0]);

        //RETURN PRODUCT FROM MENU
        Product product = menu.getMenu()[intCode];

        //PROMPT USER TO ENTER QUANTITY
        String qty = JOptionPane.showInputDialog("Enter Quantity");

        //ADD PRODUCT AND QUANTITY TO ORDER
        order.setOrderProduct(product, Integer.parseInt(qty));

    } while (JOptionPane.showConfirmDialog(null,
            "Enter More Products?",
            "User Selection",
            JOptionPane.YES_NO_OPTION,
            JOptionPane.QUESTION_MESSAGE,
            null) != JOptionPane.NO_OPTION);

    //CREATE A NEW JAVAZON STORE
    JavaZon jz = new JavaZon();

    //ADD THE ORDER TO THE STORE
    jz.setOrder(order);

    //ASSIGN A CLERK TO THE ORDER
    jz.setClerk();

    //PROCESS ORDER
    jz.processOrder();

    //DISPLAY THE RESULT
    JOptionPane.showMessageDialog(null, jz.getReceipt());
  }
}