How to check if two objects in a ArrayList are the same? [duplicate]

I want to see if two objects in the same array list are the same. Similarly if there are not objects that are the same in the array list I also want to display an appropriate message. At the moment it is printing too much. I just want it to display one line: "there are books that are the same" or "there are NO books that are the same". Here are my efforts so far.

public static void main(String[] args) {

    List<Book> listOfBooks = new ArrayList<>();
    Book book1 = new Book();
    Book book2 = new Book();
    Book book3 = new Book();

    listOfBooks.add(book1);
    listOfBooks.add(book2);
    listOfBooks.add(book3);
    listOfBooks.add(book2);

    for (Book bookA : listOfBooks) {
        for (Book bookB : listOfBooks) {
            if (bookA.equals(bookB)) {
                System.out.println("there are books that are the same");
            }
            System.out.println("there are NO books that are the same");
        }

    }
}

Thanks in advance.

EDIT: I amended my code as such according to "duplicate question"

List<Book> listOfBooks = new ArrayList<>();
    Set<Book> setOfBooks = new HashSet<Book>(listOfBooks);

    Book book1 = new Book();
    Book book2 = new Book();
    Book book3 = new Book();

    listOfBooks.add(book1);
    listOfBooks.add(book2);
    listOfBooks.add(book3);

    if (setOfBooks.size() < listOfBooks.size()) {
        System.out.println("there are duplicates");
    } else {
        System.out.println("there are no duplicates");
    }

Still prints "there are duplicates" when there clearly are not.

RESOLVED: Ordering of my code was incorrect. Solution-

    List<Book> listOfBooks = new ArrayList<>();

    Book book1 = new Book();
    Book book2 = new Book();
    Book book3 = new Book();

    listOfBooks.add(book1);
    listOfBooks.add(book2);
    listOfBooks.add(book3);

    Set<Book> setOfBooks = new HashSet<>(listOfBooks);

    if (setOfBooks.size() < listOfBooks.size()) {
        System.out.println("there are duplicates");
    } else {
        System.out.println("there are no duplicates");
    }