Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

Java Java Objects Delivering the MVP Applying a Discount Code

Dee Espo
Dee Espo
10,475 Points

Can't get this to work as applyDiscountCode was originally a void and trying to call it to a string

I know I have to have discountCode.toUpperCase(); but every combination I try is giving me syntax errors.

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;

  public String applyDiscountCode(String discountCode) {
    this.discountCode = discountCode;

 private String normalizeDiscountCode(String discountCode){
    this.discountCode = normalizeDiscountCode(discountCode);
    this.discountCode = discountCode.toUpperCase();
    return  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

Cal Song
Cal Song
13,934 Points

Ok, so what I understood from methods of code, you want to use these two methods to change the discountCode to upper case, right? (Hope so..)

Your objects would be 1. using normalize, return a code that's switched to upper case and then with the returned value, you want to set discoundCode field with that.

So first thing you need to do change normalize method to

private String normalizeDiscountCode(String discountCode){ return discountCode.toUpperCase(); }

Then you will get upper-cased discountcode. Now you want to pass that returned value to next method. And also change the type String to void.

public void applyDiscountCode(String discountCode) { this.discountCode = normalizeDiscountCode(discountCode); }

I'm not sure if that is what you are trying to accomplish since I don't have the original question. If that is not, let me know.