After you uncomment the code in Main.java and Forum.java, fix the code as described in the comments of Main.java.

public class Forum {
  private 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", 
            post.getAuthor().getFirstName(),
            post.getAuthor().getLastName(),
            post.getTitle());
  }
}

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 firstName; }

        public String getLastName() { return 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; }
    // 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");
      System.exit(1);
    }    

    Forum forum = new Forum("Java");
    User author = new User(args[0], args[1]); // Add args[0] and args[1] those are the first arguments presented which translate to firstName and lastName variables.
    ForumPost post = new ForumPost( author, "title", "description"); // Look at ForumPost.java it is looking for an author, title, and discription so put
// author, "title", and "description" inside of ForumPost(""HERE"") 
    forum.addPost(post);

// *
  }
}