Challenge after the video "Using ArrayLists" keeps asking "Did you forget to add the getExternalLinks method?

The challenge for Using ArrayLists keeps asking "Did you forget to add the getExternalLinks method? No, I wrote the method. I don't know why it can't see it.

Thanks for you help.

This is the code. package com.example;

import java.io.Serializable; import java.util.Date; import java.util.List; import java.util.Arrays; import java.util.ArrayList;

public class BlogPost implements Comparable<BlogPost>, Serializable { 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 int compareTo(BlogPost other) { if (equals(other)) { return 0; } return mCreationDate.compareTo(other.mCreationDate); }

public List<String>getWords() { String[] words = mBody.split("\s+"); return Arrays.asList(words); }

private List<String> getExternalLinks(String prefix) { List<String> results = new ArrayList<String>(); for(String word : getWords()) { if(word.startsWith(prefix)) { results.add(word); } } return results; }

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; } }

package com.example;

import java.io.Serializable;
import java.util.Date;
import java.util.List;
import java.util.Arrays;
import java.util.ArrayList;

public class BlogPost implements Comparable<BlogPost>, Serializable {
  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 int compareTo(BlogPost other) {
    if (equals(other)) {
      return 0;
    }
    return mCreationDate.compareTo(other.mCreationDate);
  }

  public List<String>getWords() {
    String[] words = mBody.split("\\s+");
    return Arrays.asList(words);
  }

  private List<String> getExternalLinks(String prefix) {
    List<String> results = new ArrayList<String>();
    for(String word : getWords()) {
      if(word.startsWith(prefix)) {
        results.add(word);
      }
    }
    return results;
  }

  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;
  }
}