Java Fundamentals Project

Description

This project covers key concepts of Object-Oriented Programming (OOP) and Java fundamentals, focusing on preparing for technical interviews. The project aims to solidify knowledge of Java keywords, data structures, interfaces, and abstract classes, while practicing OOP principles.

Project Goals

• Gain a comprehensive understanding of Object-Oriented Programming (OOP)
• Master differences among HashSet, LinkedList, ArrayList, and other Java data structures
• Study and apply access modifiers (protected, private, public)
• Familiarize with exception handling, the final keyword, interfaces, and abstract classes
• Practice essential Java keywords and prepare for common interview questions

Topics Covered

1. Classes, objects, constructors, and abstract classes
2. Interfaces and polymorphism
3. Encapsulation, inheritance, polymorphism, and abstraction
4. Data structures: ArrayList, LinkedList, HashSet, HashMap
5. Access modifiers: public, private, protected
6. Exception handling with try-catch-finally
7. Keywords: final, static, abstract, super, this, instanceof, try-catch-finally

Project Structure

Class Descriptions

• Main.java: The main class to run the project and test all implemented features.

• models/Person.java: Base class representing a person, with fields like name, age, and methods to demonstrate encapsulation and access modifiers. Use this as a foundation for inheritance.

• models/Student.java and models/Teacher.java: Extend Person to show inheritance and apply polymorphism. Add specific fields and methods for each.

• models/PersonInterface.java: Interface that defines basic methods for Person-like objects. Use this to demonstrate the implementation of interfaces and how they differ from abstract classes.

• dataStructures/CustomArrayList.java: Custom version of ArrayList to explore the properties of this data structure and explain differences with LinkedList.

• dataStructures/CustomLinkedList.java: Basic implementation of LinkedList to show how it differs from ArrayList.

• dataStructures/CustomHashSet.java: Class to demonstrate the unique properties of HashSet, especially duplicate handling and hashCode.

• utilities/AccessModifiersExample.java: Demonstrates private, protected, and public usage, showing the contexts in which each modifier is accessible.

• utilities/PolymorphismDemo.java: Shows examples of polymorphism using methods of Student and Teacher classes with instances of type Person.

• utilities/InheritanceDemo.java: Demonstrates how inheritance works among Person, Student, and Teacher.

• utilities/EncapsulationDemo.java: Provides examples of getters and setters, demonstrating encapsulation.

• keywords/FinalKeywordDemo.java: Demonstrates the final keyword with variables, methods, and classes, showing its role in creating constants and preventing inheritance or overriding.

• keywords/StaticKeywordDemo.java: Contains examples of static fields, methods, and static blocks, explaining when and why they are used.

• keywords/AbstractClassExample.java: Shows how to define and use an abstract class, including both abstract and concrete methods.

• keywords/SuperAndThisDemo.java: Demonstrates the super and this keywords for calling parent class constructors or methods, and referring to the current class instance.

• keywords/InstanceofDemo.java: Examples of the instanceof keyword, used to check object types and ensure safe casting.

• keywords/ExceptionHandlingDemo.java: Covers exception handling basics with try-catch-finally blocks, demonstrating how to use finally for resource cleanup.

• abstraction/AbstractPerson.java: An abstract class extending PersonInterface that includes both concrete and abstract methods. Demonstrates abstraction by combining interface and abstract class functionality.

• abstraction/PersonImpl.java: A concrete implementation of AbstractPerson that provides implementations for all abstract methods in AbstractPerson and methods defined in PersonInterface.