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Java Java Objects Delivering the MVP Forum

N Elliott
N Elliott
2,628 Points

I'm stuck on this last question. help

Not sure what I'm doing wrong

public class Forum {
  private String topic;

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

  public String getTopic() {
    return topic;

  //Uncomment this when you are prompted to do so
  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) {
    // TODO: set and add the private fields
    this.firstName = firstName;
    this.lastName = lastName;
  // TODO: add getters for firstName and lastName
  public String getFirstName() {
    return this.firstName;
  public String getLastName() {
    return this.lastName;
public class ForumPost {
  private User author;
  private String title;
  private String description;

  // TODO: add a constructor that accepts the author, title and 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");
    // Uncomment this when prompted
    Forum forum = new Forum("Java");
    // TODO: pass in the first name and last name that are in the args parameter
    User author = new User("John","Smith");
    // TODO: initialize the forum post with the user created above and a title and description of your choice
    ForumPost post = new ForumPost("John Smith", "A title", "A description");
    forum.addPost("this is a test post");



4 Answers

28,558 Points

There are a number of issues with your code:

  1. In the Forum class constructor you have this line this.forum = forum(topic); I'm not quite sure what the logic behind it is but it is incorrect. The constructor is meant to set the field variable called topic (this.topic) equal to the parameter called topic (topic) this is done simply like this this.topic = topic. You got the constructor correct for the ForumPost class so I'm not sure why you did it differently for this constructor.

  2. The task does not want you to supply the name of the User you create. It wants you to get the first and last name through arguments passed to the program. In Java you access program arguments though an array called args. So args[0] would be used to fetch the first argument and args[1] would be used to fetch the second one. The task wants these arguments to be used to supply the first and last name to the User object you create.

  3. The ForumPost class requires a User object as it first argument, but you pass it a string (John Smith). You are meant to pass the User you created above and stored in the author variable instead.

  4. You make a similar mistake when it comes to calling the addPost method, it takes a ForumPost object not a string. Again you are meant to pass the object you created in the above line of code.

If you fix those mistakes your code should pass.

N Elliott
N Elliott
2,628 Points

Thanks! It worked. However, I don't think Craig Dennnis covered arrays in detail in this class. The only thing he covered was .toarray This was confusing.

N Elliott
N Elliott
2,628 Points

wait, now it doesn't work.

28,558 Points

Can you post the code? If you followed all of my instructions to the letter then the code should work, as I basically listed out all of the things I changed in your code in order to get it to pass the challenge.

If you want to look at the solution in order to compare it to your code I have posted it here. It only includes the solution code for the Main.java file. But your code in the other files were already correct with the exception of the Forum constructor which I already addressed in my first post.

N Elliott
N Elliott
2,628 Points

It works as you described. Thank you Andren.