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For this written assignment, you are tasked with exploring the concepts of abstract classes and polymorphism in Java. Your 3 to 5-page paper should begin by defining what abstract classes are, explaining their purpose and role in Java programming, and how they can be used to provide a template for derived classes with shared attributes and behaviors. Then, delve into polymorphism, discussing how it allows objects of different classes to be treated as instances of a common superclass, enabling method overriding and dynamic method invocation. Illustrate these concepts with clear, practical examples, such as a class hierarchy involving different types of vehicles or animals, highlighting how abstract classes can define common methods while allowing subclasses to implement specific functionality. Discuss the benefits of using abstract classes and polymorphism in software development, including code reusability, maintainability, and flexibility, and consider potential challenges or limitations. Your paper should be well-structured, include code snippets to support your explanations, and demonstrate a thorough understanding of these key object-oriented programming principles in Java.

Objective: Implement a class hierarchy using inheritance to build a simple library management system in Java. This system will include a base class with common properties and methods shared by other classes representing different entities, such as books, patrons, librarians, and borrowing transactions. You will demonstrate how inheritance allows for code reuse and how polymorphism can be used to extend functionality.

Deliverables:

• A Java application demonstrating the class hierarchy and features outlined above.
• Commented code explaining key concepts and decisions.
• A brief written explanation of how your class hierarchy supports code reuse, encapsulation, and polymorphism.

Instructions:

1. Create a Base Class:
   1. Design a class called LibraryItem that includes common attributes like title, author, and itemId.
   2. Add methods such as displayInfo() to show details about the item.
2. Create Derived Classes:
   1. Create specific classes for different types of library items, such as Book, Magazine, and DVD, that extend the LibraryItem class.
   2. Each class should have additional attributes specific to that item type (e.g., genre for Book, issueDate for Magazine).
   3. Override the displayInfo() method to include the specific attributes of each item type.
3. Create User Classes:
   1. Design a User class with attributes like userId, name, and contactInfo.
   2. Create subclasses such as Patron and Librarian that extend User.
   3. Add specific methods for each user type, like borrowItem() for Patron and addNewItem() for Librarian.
4. Implement Transactions:
   1. Create a BorrowTransaction class to handle borrowing activities, with attributes like transactionId, user, and item.
   2. Add methods like executeTransaction() to manage the borrowing process.
5. Use Inheritance and Polymorphism:
   1. Show how derived classes inherit methods and attributes from their parent class.
   2. Use method overriding to implement polymorphism, where derived classes provide specific versions of methods defined in the base class.
6. Implement Encapsulation:
   1. Use access modifiers such as private, protected, and public to control access to class attributes and methods.
   2. Provide getter and setter methods where necessary to maintain encapsulation.
7. Consider Future Expansion:
   1. Think about how you can add more features or entities to the system in the future, such as additional item types or user roles.