Java Java Objects Delivering the MVP Applying a Discount Code

Java Objects - Applying a discount code Pt.1 - My answer won't work! Please help


Let's use your normalization skills to normalize a discount code for a Shopping Cart application. All codes should be upper cased, no matter what the user enters

For this first task, create a new private method named normalizeDiscountCode. It should take the discount code that is passed into the method and return the uppercase version. Call it from the current applyDiscountCode method and set this.discountCode to the result.


./ error: incompatible types: String cannot be converted to char this.discountCode = normalizeDiscountCode(discountCode); ^ Note: uses unchecked or unsafe operations. Note: Recompile with -Xlint:unchecked for details. Note: Some messages have been simplified; recompile with -Xdiags:verbose to get full output 1 error

Please help me as soon as possible! Thanks!
public class Order {
  private String itemName;
  private int priceInCents;
  private String discountCode;

  public Order(String itemName, int priceInCents) {
    this.itemName = itemName;
    this.priceInCents = priceInCents;

  public String getItemName() {
    return itemName;

  public int getPriceInCents() {
    return priceInCents;

  public String getDiscountCode() {
    return discountCode;
  private char normalizeDiscountCode(char discountCode) {
    discountCode = Character.toLowerCase(discountCode);
    return discountCode;
  public void applyDiscountCode(String discountCode) {
    this.discountCode = normalizeDiscountCode(discountCode);
public class Example {

  public static void main(String[] args) {
    // This is here just for example use cases.

    Order order = new Order(
            "Yoda PEZ Dispenser",

    // These are valid.  They are letters and the $ character only
    order.getDiscountCode(); // ABC

    order.getDiscountCode(); // $ALE

    try {
      // This will throw an exception because it contains numbers
    } catch (IllegalArgumentException iae) {
      System.out.println(iae.getMessage());  // Prints "Invalid discount code"
    try {
      // This will throw as well, because it contains a symbol.
    }catch (IllegalArgumentException iae) {
      System.out.println(iae.getMessage());  // Prints "Invalid discount code"


1 Answer

Daniel Turato
Daniel Turato
Java Web Development Techdegree Graduate 30,116 Points

Your code isn't working as you're assuming the discountCode in the normalize method will be a char when in fact it should be a string. So if you change the types around, it should work like this:

private String normalizeDiscountCode(String discountCode) {
    return discountCode.toLowerCase();