☕ Core Java Concepts 📌 Overview
This repository contains fundamental and advanced Core Java concepts with examples. It is designed for beginners, students, and interview preparation.
Core Java forms the foundation of Java programming and covers OOP principles, collections, exception handling, multithreading, and more.
🏗️ Topics Covered 🔹 1. Basics of Java
History & Features of Java
JVM, JRE, JDK
Data Types
Variables
Operators
Control Statements (if, switch, loops)
🔹 2. Object-Oriented Programming (OOP)
Class & Object
Constructors
Method Overloading
Method Overriding
Encapsulation
Inheritance
Polymorphism
Abstraction
Interfaces
🔹 3. Strings
String Class
String vs StringBuilder vs StringBuffer
String Methods
Immutable Nature of Strings
🔹 4. Arrays
Single Dimensional Arrays
Multi-Dimensional Arrays
Array Operations
🔹 5. Exception Handling
try-catch block
finally block
throw & throws
Custom Exceptions
🔹 6. Collections Framework
List Interface
ArrayList
LinkedList
Vector
Set Interface
HashSet
LinkedHashSet
TreeSet
Map Interface
HashMap
LinkedHashMap
TreeMap
Iterator & Comparable
🔹 7. Multithreading
Thread Class
Runnable Interface
Thread Lifecycle
Synchronization
🔹 8. File Handling
File Class
FileReader & FileWriter
BufferedReader & BufferedWriter
🔹 9. Java 8 Features
Lambda Expressions
Functional Interfaces
Stream API
Method References
Optional Class
🧠 Core Java Architecture
Java follows Write Once, Run Anywhere (WORA) principle.
Flow:
.java file → Compiler → .class file (Bytecode) → JVM → Machine Code
Components:
JDK (Java Development Kit) → Development tools
JRE (Java Runtime Environment) → Runtime environment
JVM (Java Virtual Machine) → Executes bytecode
🛠️ Requirements
JDK 8 or above
IDE (Eclipse / IntelliJ / VS Code)
Command Line (optional)
Import project
Run the main method
View output in console
📂 Project Structure CoreJava/ │ ├── basics/ ├── oop/ ├── collections/ ├── exception/ ├── multithreading/ ├── filehandling/ └── java8/ 🎯 Purpose
Strengthen Java fundamentals
Prepare for technical interviews
Build strong programming base
Understand backend development concepts
🚀 Future Enhancements
Add JDBC
Add Design Patterns
Add Mini Projects
Add Unit Testing