Merge pull request #1 from nuwanthikaishani/nuwanthikaishani-patch-1

Update README.md

Author: nuwanthikaishani

README.md

@@ -1 +1,66 @@
-Code snippets and mini-projects to understand and practice OOP principles in Java.
+# 📘 OOP Concepts in Java – Example Codes  
+
+A collection of **beginner-to-advanced examples** that demonstrate the core principles of **Object-Oriented Programming (OOP)** using Java.  
+This repository is designed to help students, beginners, and interview candidates **understand, practice, and master OOP** with small, practical code snippets.  
+
+---
+
+## 🎯 What You’ll Learn
+- ✅ Classes & Objects  
+- ✅ Encapsulation  
+- ✅ Inheritance  
+- ✅ Polymorphism (Overloading & Overriding)  
+- ✅ Abstraction (Abstract classes & Interfaces)  
+- ✅ Composition, Aggregation & Association  
+- ✅ Static & Final usage  
+- ✅ Constructor Overloading  
+- ✅ Inner Classes  
+- ✅ Enums  
+- ✅ Interfaces & Multiple Inheritance  
+- ✅ Design Patterns (Singleton, Factory, Strategy, Observer)  
+
+---
+## 📂 Project Structure
+
+
+```text
+oop-concepts-examples/
+│
+├── encapsulation/       # Getters/Setters, Private fields, Immutable classes
+├── inheritance/         # Parent/Child classes, Super/Override
+├── polymorphism/        # Overloading, Overriding, Interfaces
+├── abstraction/         # Abstract classes & methods, Interfaces
+├── composition/         # HAS-A relationships (Car → Engine)
+├── association/         # Teacher–Student, Department–Professors
+├── static-final/        # Static methods, Constants
+├── constructors/        # Constructor overloading examples
+├── inner-classes/       # Static & Non-static inner classes
+├── enums/               # Day, OrderStatus enums
+├── interfaces/          # Multiple inheritance with interfaces
+└── design-patterns/     # Singleton, Factory, Strategy, Observer
+
+
+```
+
+## 🚀 Getting Started
+### 1. Clone the repository
+```bash
+git clone https://github.com/nuwanthikaishani/oop-fundamentals-java
+cd oop-fundamentals-java
+```
+
+### 2. Compile and Run
+```bash
+cd src/encapsulation
+javac EncapsulationDemo.java
+java EncapsulationDemo
+```
+
+## 🎓 Who Is This For?
+- ✅ Students learning Java OOP for the first time
+- ✅ Developers preparing for coding interviews
+- ✅ Anyone who wants a quick refresher on OOP principles
+
+
+
+