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Java Java Data Structures Getting There Type Casting

Kenzo Qui
Kenzo Qui
2,350 Points
Posted by Kenzo Qui
Kenzo Qui
2,350 Points

Is not initialized

It says it is probably not initialized. I believe this is wrong and I do not know what am I doing

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 = true;

  public static String getTitleFromObject(Object obj) {
    // Fix this result variable to be the correct string.
    String result;
    if ((obj instanceof String)) {
      String a = (String) obj;
      result = a;
    }

    if ((obj instanceof BlogPost)) {
      BlogPost a = ((BlogPost) obj);
      result = a.getTitle();
    }

    return result;

  }
}

1 Answer

andren
andren
28,558 Points
andren
andren
28,558 Points

It doesn't say it's probably not initialized, it says it might not be initialized, which is true since it is only given a value within the two if statements. If neither of those statements run then result won't have any value when Java reaches the return statement.

Since a variable has to have a value in order to be returned the Java compiler does not allow you to return variables that are only given values conditionally. This can be fixed by simply setting result equal to an empty string when you declare it.

On top of that you have one of the challenge hints enabled, those have to be disabled before you can pass the challenge.

If you fix those two issues like this:

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; // Turn off this hint

  public static String getTitleFromObject(Object obj) {
    // Fix this result variable to be the correct string.
    String result = ""; // Initialize result as empty string
    if ((obj instanceof String)) {
      String a = (String) obj;
      result = a;
    }

    if ((obj instanceof BlogPost)) {
      BlogPost a = ((BlogPost) obj);
      result = a.getTitle();
    }

    return result;

  }
}

Then your code will work.

Kenzo Qui
Kenzo Qui
2,350 Points
Kenzo Qui
Kenzo Qui
2,350 Points

Thank you very much. I will think about this anytime I'm working with strings on java.