java arraylist class program [closed]

im confused with a question which i was given, which is about bookshelf program. I have to create 2 classes called Book and BookShelf

I have more or less completed the Book class which contains these variables (id, author and title) with ( get, set , toString and constructors methods)

However for the BookShelf class, I am kind of clueless whether what i have done is correct

Here is what I am supposed to do at the BookShelf class

• Create an addBook method, it takes in book object as input and adds the object into the bookshelf

• returnBooks method, no parameter / arguments needed just return an arraylist of books in order

• returnAuthorBooks, takes in author as input and returns an arraylist of books by the author

This is the code that i have done

import java.util.ArrayList;  
import java.util.Collections;

public class BookShelf {
    ArrayList<Book> listOfBooks = new ArrayList<Book>();

    public void addBook(Book getTitle){
        listOfBooks.add(getTitle);
    }

    public ArrayList<Book> returnBooks(){

        ArrayList myBook = new ArrayList();
        Collections.sort(myBook);
        return myBook;
    }

    public ArrayList<Book> returnAuthor(Book author){

        for (Book books : listOfBooks){
            if (author.getAuthor() == books.getTitle()){
                return listOfBooks;
            }
        }
        return null;
    }
}

Would like to clarify if there is any mistake here as for some reason i get the feeling that i have done something incorrect