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Java Java Objects Delivering the MVP Forum

Code Challenge Forum task 4 of 4

I've been trying for a while and can't understand what I am doing wrong

public class Forum {
  private String topic;

  // TODO: add a constructor that accepts a topic and sets the private field topic

  public String getTopic() {
    return topic;

  private Forum(String topic) {
   this.topic = topic;

  public void addPost(ForumPost post) {
    System.out.printf("A new post in %s topic from %s %s about %s is available",

public class User {
  private String firstName;
  private String lastName;
  // TODO: add private fields for firstName and lastName

  public User(String firstName, String lastName) {
    this.firstName = firstName;
    this.lastName = lastName;
    // TODO: set and add the private fields


  public String getLastName() {
   return lastName;

  public String getFirstName() {
   return firstName;

  // TODO: add getters for firstName and lastName

public class ForumPost {
  private User author;
  private String title;
  private String description;

   public ForumPost(User author, String title, String description) {
    this.author = author;
    this.description = description;
    this.title = title;
  // TODO: add a constructor that accepts the author, title and description

  public User getAuthor() {
    return author;

  public String getTitle() {
    return title;

  public String getDescription() {
    return description;
public class Main {

  public static void main(String[] args) {
    System.out.println("Beginning forum example");
    if (args.length < 2) {
      System.out.println("Usage: java Main <first name> <last name>");
      System.err.println("<first name> and <last name> are required");

    Forum forum = new Forum("Java");

    User author = new User(args[0], args[1]);

    ForumPost post = new ForumPost(author, "another day", "Wahoo!");




1 Answer

28,558 Points

There are two issues I can see in your code:

  1. You have made the constructor in the forum class private. Which means that it cannot actually be called from any other class, which makes it somewhat useless as a constructor.

  2. On the last line of Main.java you have changed forum to Forum. Meaning that you are referencing the Forum class rather than the forum object created above. This is not a change you were supposed to make.

If you fix the Forum constructor so that it looks like this:

public Forum(String topic) { // Changed private to public
    this.topic = topic;

And fix the last line in Main.Java so that it looks like this:

forum.addPost(post); // Changed Forum to forum

Then your code should work.

Thank you for the help