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Start your free trialRushabha Jain
Front End Web Development Techdegree Student 9,859 Pointsconfusing
Showing Error on line 18
package com.example;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Set;
import java.util.TreeSet;
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.*;
public class Blog {
List<BlogPost> mPosts;
public Blog(List<BlogPost> posts) {
mPosts = posts;
}
public List<BlogPost> getPosts() {
return mPosts;
}
public Set<String> getAllAuthors(){
Set<String> set = new TreeSet<String>();
set.addAll(getPosts()); //Showing Error Here
return set;
}
}
Rushabha Jain
Front End Web Development Techdegree Student 9,859 Points./com/example/Blog.java:16: error: cannot find symbol
public Set getAllAuthors(){
^
symbol: class Set
location: class Blog
./com/example/Blog.java:17: error: cannot find symbol
Set set = new TreeSet();
^
symbol: class Set
location: class Blog
./com/example/Blog.java:17: error: cannot find symbol
Set set = new TreeSet();
^
symbol: class TreeSet
location: class Blog
Note: JavaTester.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
3 errors
1 Answer
Chris Freeman
Treehouse Moderator 68,441 PointsAccording to the error log it can not find symbols Set
and Treeset
. Have they been imported?
After running your code in the challenge, I get a different error trace:
./com/example/Blog.java:18: error: no suitable method found for addAll(List)
set.addAll(getPosts()); //Showing Error Here
^
method Collection.addAll(Collection) is not applicable
(argument mismatch; List cannot be converted to Collection)
method Set.addAll(Collection) is not applicable
(argument mismatch; List cannot be converted to Collection)
Note: JavaTester.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
1 error
You are trying to use addAll()
to add a List
of BlogPost
s to a Set
of Strings
. The challenge only wants the authors in the list.
Loop over the BlogPost List and add each author returned from post.getAuthor()
Rushabha Jain
Front End Web Development Techdegree Student 9,859 PointsYup,i imported
Chris Freeman
Treehouse Moderator 68,441 PointsTry explicit importing in Blog.java.
lambda
12,556 PointsRushabha Jain, you imported in BlogPost.java but you didn't import in Blog.java. You have to import in both Java files.
Chris Freeman
Treehouse Moderator 68,441 PointsRan your code, updated Answer.
Chris Freeman
Treehouse Moderator 68,441 PointsChris Freeman
Treehouse Moderator 68,441 PointsCan you post the full error message?