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![Jonathan Kalbfeld](https://uploads.teamtreehouse.com/production/profile-photos/2839852/micro_jonathan-kalbfeld-adj.jpg)
Jonathan Kalbfeld
11,888 PointsWhy do I see java.lang.InvocationTargetException
When I run this code, this is what I see
package com.example;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
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() {
List<String> links = new ArrayList<String>();
for (String word : getWords()) {
if (word.startsWith("http")) {
links.add(word);
}
}
return links;
}
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.util.List;
import java.util.Set;
import java.util.TreeSet;
import java.util.Map;
import java.util.HashMap;
public class Blog {
List<BlogPost> mPosts;
public Map<String, Integer> getCategoryCounts() {
Map<String, Integer> categoryCounts = new HashMap<String, Integer>();
for (BlogPost bp : mPosts) {
int counts = categoryCounts.get(bp.getCategory());
counts++;
categoryCounts.put(bp.getCategory(),counts);
}
return categoryCounts;
}
public Blog(List<BlogPost> posts) {
mPosts = posts;
}
public List<BlogPost> getPosts() {
return mPosts;
}
public Set<String> getAllAuthors() {
Set<String> authors = new TreeSet<>();
for (BlogPost post: mPosts) {
authors.add(post.getAuthor());
}
return authors;
}
}
1 Answer
![Craig Dennis](https://secure.gravatar.com/avatar/950c867932cc1483d8aa3dad92c4cb81?s=96&d=https%3A%2F%2Fecs-static.teamtreehouse.com%2Fassets%2Fcontent%2Fdefault_avatar-445fbbabfc8dc9188fb5967fe43322ee0c3e0dd1e10f378bf8343784af5a13eb.webp&r=pg)
Craig Dennis
Treehouse TeacherRemember counts might be null
if it doesn't exist in the map. You need to set it to 0
specifically. null++
doesn't work.
Carter Pringle
3,416 PointsCarter Pringle
3,416 PointsWhat line does it give the error for?