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Start your free trialRebecca Fuller
7,990 PointsJava Objects: Forum: Task 4 of 4 - Error Message
I'm not understanding why I keep getting this error message, I haven't even changed this line of code...
public class Forum {
private String topic;
// TODO: add a constructor that accepts a topic and sets the private field topic
public void getTopic (String topic) {
topic = this.topic;
}
public String getTopic() {
return topic;
}
public void addPost(ForumPost post) {
System.out.printf("A new post in %s topic from %s %s about %s is available",
topic,
post.getAuthor().getFirstName(),
post.getAuthor().getLastName(),
post.getTitle()
);
}
}
public class User {
// TODO: add private fields for firstName and lastName
private String firstName;
private String lastName;
public User(String firstName, String lastName) {
// TODO: set and add the private fields
firstName = this.firstName;
lastName = this.lastName;
}
// TODO: add getters for firstName and lastName
public String getFirstName() {
return firstName;
}
public String getLastName() {
return lastName;
}
}
public class ForumPost {
private User author;
private String title;
private String description;
// TODO: add a constructor that accepts the author, title and description
public void getInfo(User author, String title, String description) {
author = this.author;
title = this.title;
description = this.description;
}
public User getAuthor() {
return author;
}
public String getTitle() {
return title;
}
public String getDescription() {
return description;
}
}
public class Main {
public static void main(String[] args) {
System.out.println("Beginning forum example");
if (args.length < 2) {
System.out.println("Usage: java Main <first name> <last name>");
System.err.println("<first name> and <last name> are required");
System.exit(1);
}
Forum forum = new Forum("Java");
// TODO: pass in the first name and last name that are in the args parameter
User author = new User(args[0], args[1]);
// TODO: initialize the forum post with the user created above and a title and description of your choice
ForumPost post = new ForumPost();
forum.addPost(post);
}
}
1 Answer
ofir moalmi
2,161 PointsI'm new to java as well so Im not too sure but I did notice that you dont have a constructor, add constructors where needed, for the Forum class its public Forum(String topic){ topic = this.topic;
}
and same goes for your ForumPost class.
edit: I just tried out the challnge aswell and got stuck, and apparently what caused the errors is using variable = this.variable; instead of this.variable = variable; im still having confusion about what this. actually refers to.
and you also don't have an parameters in your ForumPost post object.
Rebecca Fuller
7,990 PointsRebecca Fuller
7,990 PointsSorry forgot to include the error message:
./Main.java:10: error: constructor Forum in class Forum cannot be applied to given types; Forum forum = new Forum("Java"); ^ required: no arguments found: String reason: actual and formal argument lists differ in length Note: JavaTester.java uses unchecked or unsafe operations. Note: Recompile with -Xlint:unchecked for details. 1 error