Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

Java Java Data Structures - Retired Getting There Type Casting

Tulrose Deori
Tulrose Deori
266 Points

I'm stuck at TypeCasting Exercise. I'd downcasted it. But I'm not sure how to convert bp to String.

import com.example.BlogPost;

public class TypeCastChecker {

  public static boolean HINT_1_ENABLED = false;
  public static boolean HINT_2_ENABLED = false;

  public static String getTitleFromObject(Object obj) {
    // Fix this result variable to be the correct string.

    String result = "";
    if (result instanceof Object)
      result = (String) obj;
    return result;

    if (obj instanceof BlogPost)
      BlogPost bp = (BlogPost) obj;      

  }
}
com/example/BlogPost.java
package com.example;

import java.util.Date;

public class BlogPost {
    private String mAuthor;
    private String mTitle;
    private String mBody;
    private String mCategory;
    private Date mCreationDate;

    public BlogPost(String author, String title, String body, String category, Date creationDate) {
      mAuthor = author;
      mTitle = title;
      mBody = body;
      mCategory = category;
      mCreationDate = creationDate;
    }

    public String getAuthor() {
      return mAuthor;
    }

    public String getTitle() {
      return mTitle;
    }

    public String getBody() {
      return mBody;
    }

    public String getCategory() {
      return mCategory;
    }

    public Date getCreationDate() {
      return mCreationDate;
    }
}
TypeCastChecker.java
import com.example.BlogPost;

public class TypeCastChecker {
  /***************
  I have provided 2 hints for this challenge.
  Change `false` to `true` in one line below, then click the "Check work" button to see the hint.
  NOTE: You must set all the hints to false to complete the exercise.
  ****************/
  public static boolean HINT_1_ENABLED = false;
  public static boolean HINT_2_ENABLED = false;

  public static String getTitleFromObject(Object obj) {
    // Fix this result variable to be the correct string.

    String result = "";
    if (result instanceof Object)
      result = (String) obj;

    if (obj instanceof BlogPost)
      BlogPost bp = (BlogPost) obj;



  }
}

1 Answer

Caleb Kleveter
MOD
Caleb Kleveter
Treehouse Moderator 37,862 Points

If I am correct, you can't cast an object that is not a String to a String, so you have to use the String.valueOf method instead:

result = String.valueOf(bp);
Tulrose Deori
Tulrose Deori
266 Points

Thank You, Caleb. I appended it to my code. It works perfectly and I'll be sure to dig in how valueOf() works.