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Java Java Objects Delivering the MVP Forum

How do I initialize a user?

I've tried everything I can think of but I keep getting compiler errors. What did I do wrong?

public class Forum {
  private String topic;
public Forum(String topic) {
 this.topic = topic; 
  // TODO: add a constructor that accepts a topic and sets the private field topic

  public String getTopic() {
    return 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 {
  // TODO: add private fields for firstName and lastName
private String firstName;
  private String lastName;

  public User(String firstName, String lastName) {
this.firstName = firstName;
this.lastName = lastName;
public String getFirstName() {
  return firstName;
  public String getLastName() {
  return lastName;
  // 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.title = title;
  this.description = 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");
    String firstName = args[0];
    String lastName = args[0];
    User author = new User();

    // TODO: initialize the forum post with the user created above and a title and description of your choice

    ForumPost post = new ForumPost(author, "food",  "nothing");



1 Answer

Steven Parker
Steven Parker
229,644 Points

First step first! Task 1 isn't about creating a user, it's: "Add a constructor that accepts a String named topic to Forum.java. Initialize the private field topic in the constructor to the value passed in."

The "TODO" line is still visible in the file above, but the constructor hasn't been created yet.

Once you've completed that task and the challenge gives you a "Well done!" then continue, performing each step one at a time. At each step, do only what the challenge instructions ask!