JavaExercises

A comprehensive collection of Java programming exercises focused on Object-Oriented Programming (OOP) principles and Design Patterns. This repository contains practical implementations of various design patterns and demonstrates core OOP concepts like interfaces, inheritance, polymorphism, and abstraction.

📋 Table of Contents

• Overview
• Technologies
• Project Structure
• Assignments
• How to Run
• Learning Objectives

🎯 Overview

This repository serves as a learning resource for mastering Java programming with a focus on:

• Object-Oriented Programming principles
• Design Pattern implementations
• Interface-based design
• Inheritance and Polymorphism
• Code organization and best practices

🛠 Technologies

• Java: Core programming language
• IDE: IntelliJ IDEA (project files included)
• Build System: Standard Java compilation

Prerequisites

• Java Development Kit (JDK) 8 or higher
• IntelliJ IDEA (recommended) or any Java IDE
• Basic understanding of Java and OOP concepts

📁 Project Structure

JavaExercises/
├── Assignment1/          # Interfaces, Inheritance, and Polymorphism
├── Assingment2/          # Factory/Strategy Pattern
├── Assignment3/          # Abstract Factory Pattern
├── Assignment4/          # (In Development)
├── Assignment5/          # State Pattern
├── .gitignore            # Git ignore configuration
└── README.md             # This file

📚 Assignments

Assignment 1: Interfaces and Polymorphism

Concepts: Interface implementation, Inheritance, Downcasting, Polymorphism

This assignment demonstrates the power of interfaces in Java through a flight-tracking system. Multiple entities (Birds, Drones, Satellites, UFOs, etc.) implement various interfaces based on their capabilities.

Key Interfaces:

• IFlightEnabled - For entities that can fly
• ITrackable - For entities that can be tracked
• INavigable - For navigation capabilities
• IAutopilot - For autonomous control
• ICameraEnabled - For image capture
• ISensorEquipped - For sensor-equipped entities
• IOrbitEarth - For orbiting objects
• And more...

Classes Implemented:

• Animal hierarchy (Bird, Bee, Dolphin)
• Aircraft (Jet, Drone, ReconDrone, Glider)
• Space objects (Satellite, SpaceProbe, AlienShip, UFO)
• Vehicles (Truck, SelfDrivingCar, AutonomousBoat)
• Special entities (Missile, WeatherBalloon, DragonFly)

Assignment 2: Factory/Strategy Pattern

Concepts: Factory Pattern, Strategy Pattern, Dependency Injection

A pizza ordering system demonstrating the Factory pattern where different types of pizzas (Italian, Spanish, Senegalese) are created and served by chefs.

Implementation:

• Chef - Factory class that creates pizzas
• Pizza - Abstract pizza class
• PizzaItalian, PizzaSpanish, PizzaSenegal - Concrete pizza implementations
• IPizzaPizza - Pizza interface

Assignment 3: Abstract Factory Pattern

Concepts: Abstract Factory Pattern, Product Families

A vehicle manufacturing system demonstrating the Abstract Factory pattern with two brands (Mercedes and Volvo) and two vehicle types (Car and Truck).

Implementation:

• AbstractFactory - Main factory interface
• CarFactory, TruckFactory - Concrete factory implementations
• Mercedes, Volvo - Abstract product classes
• MercedesCar, MercedesTruck, VolvoCar, VolvoTruck - Concrete products

Assignment 4: (In Development)

Currently under development. Check back for updates.

Assignment 5: State Pattern

Concepts: State Pattern, Behavioral Design Patterns

Demonstrates the State pattern through a Lion's mood system. The assignment includes both "before" and "after" implementations to show the improvement gained by using the State pattern.

Implementation:

• Before: Direct state management within the Lion class
• After: Clean separation using state objects
  • Lion - Context class
  • IState - State interface
  • Hungry, NotHungry, Angry - Concrete state implementations

The lion changes states interactively based on user input, demonstrating how the State pattern encapsulates state-specific behavior.

🚀 How to Run

Using IntelliJ IDEA (Recommended)

1. Clone the repository:

   git clone https://github.com/JavaProjects25/JavaExercises.git
   cd JavaExercises

2. Open the project in IntelliJ IDEA:

   • File → Open → Select the JavaExercises directory

3. Navigate to any assignment folder (e.g., Assignment1)

4. Locate the Main.java file in the src directory

5. Right-click on Main.java and select "Run Main.main()"

Using Command Line

1. Navigate to the assignment directory:

   cd Assignment1/JavaClass\ -\ Assignment01/src

2. Compile the Java files:

   javac *.java

3. Run the Main class:

   java Main

Running Specific Assignments

• Assignment 1: Run Main.java in Assignment1/JavaClass - Assignment01/src/
• Assignment 2: Run Main.java in Assingment2/src/
• Assignment 3: Run Main.java in Assignment3/src/
• Assignment 5:
  • Before State: Run Main.java in Assignment5/src/BeforeState/
  • After State: Run Main.java in Assignment5/src/AfterState/ (interactive)

🎓 Learning Objectives

By working through these assignments, you will learn:

1. Interface-Based Design

   • Creating and implementing multiple interfaces
   • Understanding interface segregation
   • Working with polymorphism through interfaces

2. Design Patterns

   • Factory Pattern: Creating objects without specifying exact classes
   • Abstract Factory Pattern: Creating families of related objects
   • State Pattern: Changing object behavior based on internal state

3. OOP Principles

   • Encapsulation: Hiding internal details
   • Inheritance: Building class hierarchies
   • Polymorphism: One interface, multiple implementations
   • Abstraction: Working with abstract concepts

4. Best Practices

   • Code organization and structure
   • Separation of concerns
   • Clean code principles
   • Design pattern application

📝 Notes

• Each assignment is self-contained and can be run independently
• Diagram files (.drawio) are included for visual representation of patterns
• The project uses IntelliJ IDEA project structure (.iml files)

🤝 Contributing

This is a learning repository. Feel free to:

• Report issues or bugs
• Suggest improvements
• Add more design pattern examples
• Enhance documentation

📄 License

This project is for educational purposes.

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Happy Learning! 🚀