please help to separate the different classes, test and answer by some indication or line.

Problem Description: 1. (50pts) Imagine a pile of books on your desk. Each book is so large and heavy that you can remove only the top one from the pile. You cannot remove a book from under another one. Likewise, you cannot add a book beneath another one. You can add another book to the pile only by placing it on the top of the pile. If you represent books by their titles alone, design a class that you can use to track the books in the pile on your desk. Specify each operation by stating its purpose, by describing its parameters, and by writing a pseudocode version of its header. Then write a Java interface for the pile's methods. Include javadoc-style comments in your code. 2. (50pts) Define a class PileOfBooks that implements the interface described in the previous question. Use a resizable array in your implementation. Then write a program that adequately demonstrates your implementation(Like a tester class that creates an empty object and check to see if it is empty or we can add items to the bag)