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

Fahri Can
Fahri Can
9,921 Points

Why I am getting a syntax error for typecasting?

Need help, please ..

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(obj instanceof BlogPost){
      return (String) obj.getTitle();
    }
    return result; 
  }
}

1 Answer

Steven Parker
Steven Parker
231,007 Points

:point_right: The error seems to be an undefined method.

Assuming you are working on task 1, I can see two issues here. The challenge says, "return the object obj type casted as a String if it is in fact a String". But instead of checking to see if the object is a String, the code above checks if it is a BlogPost.

Also, instead of returning the object itself, the code attempts to return the result of calling a .getTitle() method on the object (which is not an Object method).

On the other hand, if you're working on task 2, you have some other issues. First, you should not modify the task 1 code, but add to it. Then, you'll need to cast the object to the correct type. And finally, the cast must be applied before you can use the getTitle method on it.