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Java Java Objects (Retired) Delivering the MVP Wrapping up

Neelesh Tewani
Neelesh Tewani
1,239 Points

i want to know the problem in the fourth task of this challenge

ForumPost post = new ForumPost(author.getFirstName(),author.getLastName(),"challenge completed","yes i have done the challenge");

ForumPost.java
public class ForumPost {
  private User mAuthor;
  private String mTitle;
  private String mDescription;
public ForumPost(User nAuthor,String title,String description){
  nAuthor=mAuthor;
    mTitle = title;
    description= mDescription;
  }
  public String getDescription(){
  return mDescription;
  }


  public User getAuthor() {
    return mAuthor;
  }


  public String getTitle() {
    return mTitle;
  }

  // TODO: We need to expose the description
}
User.java
public class User {
  private String mFirstName;
   private String mLastName;

  public User(String firstName, String lastName) {
    // TODO:  Set the private fields here    

 mFirstName = firstName;
    mLastName = lastName;
  }

  public String getFirstName(){
return mFirstName;
  }
  public String getLastName(){
  return mLastName;
  }
}
Forum.java
public class Forum {
  private String mTopic;

  public String getTopic() {
      return mTopic;
  }
    public Forum(String ltopic){
mTopic = ltopic;
  }


  public void addPost(ForumPost post) {
      System.out.printf("New post from %s %s about %s.\n",
                         post.getAuthor().getFirstName(),
                         post.getAuthor().getLastName(),
                         post.getTitle());

  }
}
Example.java
public class Example {

  public static void main(String[] args) {
    System.out.println("Starting forum example...");
    if (args.length < 2) {
       System.out.println("first and last name are required. eg:  java Example Craig Dennis");
    }
     Forum forum = new Forum("Java");
    // Take the first two elements passed args
    User author = new User("Neelesh","Tewani");
    // Add the author, title and description
    ForumPost post = new ForumPost(author.getFirstName(),author.getLastName(),"challenge completed","yes i have done the challenge");
    forum.addPost(post);
  }
}

4 Answers

Kevin Faust
Kevin Faust
15,353 Points

Hey Neelesh,

So first off, let's look at this:

ForumPost post = new ForumPost(author.getFirstName(),author.getLastName(),"challenge completed","yes i have done the challenge");

Before we do anything, analyze what you wrote, You are basically putting 4 strings as constructor parameters. Look at our ForumPost class:

public ForumPost(User nAuthor,String title,String description)

It takes a User object, and two Strings right?

Look at this:

 User author = new User("Neelesh","Tewani");

Here we created a User object right? That is what we pas in as our first paramter

Here is what it should look like:

ForumPost post = new ForumPost( author , "string text" , "string text" );

Ok it looks great now right? Oh wait it's still not working.

[ https://teamtreehouse.com/community/output-is-appropriate-in-editor-but-still-fails-challenge ]

Here's a link to my answer that will guide you through the remaining of what you need to do. I've written a in-depth explanation of what you will have to do.

Let me know if you got everythin working,

Happy coding and best of luck,

Kevin

I see a few issues here. First, your

ForumPost

constructor just takes the

User

as its first argument, so you should have

ForumPost post = new ForumPost(author,"challenge completed","yes i have done the challenge");

in Example.java.

Second, the task asks you to create the author

User

from the arguments passed to main.

Finally you've got

nAuthor

and

mAuthor

switched in the

ForumPost

constructor so you set the argument equal to the member rather than the other way around. Once you've fixed those three issues it should work.

Neelesh Tewani
Neelesh Tewani
1,239 Points

I still didn't understand can you show me practically

Neelesh Tewani
Neelesh Tewani
1,239 Points

/* still not solved Bummer! java.lang.NullPointerException (Look around Forum.java line 15)*/

Forum forum = new Forum("Java"); // Take the first two elements passed args User author = new User("neelesh","tewani"); // Add the author, title and description ForumPost post = new ForumPost(author,"challenge accepted","you have completed the challenge"); forum.addPost(post); } }

Kevin Faust
Kevin Faust
15,353 Points

Neelesh; I need you to go click the link I posted above. I have a in depth expanation on how to solve your current problem. thanks