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Start your free trialBrecht Philips
8,863 Pointsi get a NullPointerException At Class Forum line 14 but i can't seem to find the mistake i made
How do you give Args to the main programe?
public class ForumPost {
private User mAuthor;
private String mTitle;
private String mDescription;
public ForumPost(User author,String title,String description){
User mAuthor = author;
String mTitle = title;
String mDescription = description;
}
public User getAuthor() {
return mAuthor;
}
public String getTitle() {
return mTitle;
}
public String getDescription(){
return mDescription;
}
public void setDescription(String name){
mDescription = name;
}
// TODO: We need to expose the description
}
public class User {
private String mFirstName;
private String mLastName;
public User(String firstName, String lastName) {
// TODO: Set the private fields here
mFirstName = firstName;
mLastName = lastName;
}
public String getFirstName(){
return mFirstName;
}
public String getLastName(){
return mLastName;
}
public void setFirstName(String name){
mFirstName = name;
}
public void setLastName(String name){
mLastName= name;
}
}
public class Forum {
private String mTopic;
public Forum(String topic){
mTopic=topic;
}
public String getTopic() {
return mTopic;
}
public void addPost(ForumPost post) {
// When all is ready uncomment this...
System.out.printf("New post from %s %s about %s.\n",
post.getAuthor().getFirstName(),
post.getAuthor().getLastName(),
post.getTitle());
}
}
public class Example {
public static void main(String[] args) {
System.out.println("Starting forum example...");
if (args.length < 2) {
System.out.println("first and last name are required. eg: java Example Craig Dennis");
}
Forum forum = new Forum("Java");
// Take the first two elements passed args
User author = new User("Brecht","Philips");
// Add the author, title and description
ForumPost post = new ForumPost(author,"hello","it");
forum.addPost(post);
}
}
1 Answer
Kourosh Raeen
23,733 PointsThe first name and last name values are coming in the args array. In Example.java file, change:
User author = new User("Brecht","Philips");
to:
User author = new User(args[0], args[1]);