Java Java Data Structures Exploring the Java Collection Framework ArrayLists

Tony Williams
Tony Williams
2,665 Points

I followed my method to match similar code to the video before. Is my thought process wrong?

Based on the video before and the hint "use getWords" I figured our method would be very similar to the video content before where we made a method private and called that method inside the other public methods so we wouldn't be duplicating code. Is my though process wrong and if so can someone guide me a little so I can code in a better direction?



package com.example;

import java.util.Date;
import java.util.ArrayList;
import java.util.Arrays;
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 String[] getWords() {
    return mBody.split("\\s+");

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

1 Answer

Hi Tony. You're very close.

Right now, you are not passing "http" anywhere. The method you've written is returning a list of Strings starting with a given prefix. To get the list of links, you would have to call the method elsewhere, passing in "http" as the argument: getExternalLinks("http");

Since we want this method to return links (starting with http) and only that, it does not need any argument. You can remove String prefix and just pass "http" in your startsWith() method.

Finally, don't forget to add List to your imports.

Hope that helps :)