What is wrong with my code? In JAVA

Question

i think I fullfill all requirements but still it pops up that errors exist. Where should I begin with?

Forum.java

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


}

User.java

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

    public String getLastName(){
      return lastName;
    }
  // TODO: add getters for firstName and lastName

}

ForumPost.java

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

  // TODO: add a constructor that accepts the author, title and description
private 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;
  }
}

Main.java

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");
    // TODO: pass in the first na"Java"me and last name that are in the args parameter
    User author = new User("Jiho", "Song");
    // TODO: initialize the forum post with the user created above and a title and description of your choice
    ForumPost post = new ForumPost(User("Jiho", "Song"), "Java Novice", "Really Good");
    forum.addPost(post);


  }

}

Answer 1 · 2017-01-08T11:58:13Z

January 8, 2017 11:58am

There are a number of issues with your code:

All of the constructors you have written are declared as private, when you declare a constructor as private it can't be accessed outside the class. Since the main purpose of a constructor is to be called in other classes in order to instantiate the class, it makes little sense to mark them as private. So you need to change all of them from being private to being public.
You have a typo in the name of your ForumPost constructor. You have named it "Forumpost" when it should be named "ForumPost".
When you instantiate the User class into the author variable you hardcode the first and last name to your own first and last name. The comment above the variable specifies that you have to use the first and last name that is passed into the program as arguments. In Java you access program arguments though the args array. So to get the first name you would use args[0], to get the last name you would use args[1].
When you instantiate the ForumPost class into the post variable you pass "User("Jiho", "Song")" as the user, this is invalid because you can't pass pass a class along in this way, if you wanted to create a new user in line you would have to add the new keyword before the class name. In addition you are not actually meant to create a new User in this line, but use the User you created above which is stored in the author variable.

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Jiho Song

Jiho Song

What is wrong with my code? In JAVA

1 Answer

andren

andren

Jiho Song

Jiho Song