☕ Java OOP & Data Structures and Algorithms

A comprehensive collection of Java programs covering Object-Oriented Programming concepts and Data Structures & Algorithms, organized by topic for easy navigation and learning.

---

📁 Project Structure

JavaProjects/
│
├── 📂 ArrayList
├── 📂 ArrayProblems
├── 📂 BitwiseOperatorsInJava
├── 📂 CharacterMethodsInJava
├── 📂 DataStructureAndAlgorithm
├── 📂 FactorialCalculator
├── 📂 FibonacciCalculator
├── 📂 FileHandling
├── 📂 FindingRootsOfEquation
├── 📂 FindingSystemTime
├── 📂 Function
├── 📂 GeneratingRandomNumbers
├── 📂 GPACalculator
├── 📂 GradeBookClass
├── 📂 JavaDateTimeAPI
├── 📂 LeetCodeProblems
├── 📂 MaximumAndMinimumFinder
├── 📂 MiscellaneousProblem
├── 📂 MultiThreadingInJava
├── 📂 RecursionProblems
├── 📂 RegularExpressionInJava
├── 📂 SearchingAlgorithm
├── 📂 SortingAlgorithm
├── 📂 StringsInJava
└── 📂 TCP&SMTPClientAndServer

---

📚 Topics Covered

🔷 Object-Oriented Programming (OOP)

Folder	Description
GradeBookClass	Class design, constructors, methods, and encapsulation
GPACalculator	OOP-based GPA computation using classes and objects
Function	Method overloading, return types, and parameters
GeneratingRandomNumbers	Utility class usage and Java standard library
FileHandling	File I/O using FileReader, FileWriter, BufferedReader
MultiThreadingInJava	Threads, Runnable, synchronized, and concurrency
RegularExpressionInJava	Pattern matching using java.util.regex
JavaDateTimeAPI	LocalDate, LocalTime, DateTimeFormatter
TCP&SMTPClientAndServer	Socket programming, networking with Java
CharacterMethodsInJava	Character class utility methods
StringsInJava	String manipulation, StringBuilder, common methods
BitwiseOperatorsInJava	Bitwise AND, OR, XOR, shift operators

---

🔶 Data Structures & Algorithms (DSA)

Folder	Description
DataStructureAndAlgorithm	Core DSA concepts and implementations
ArrayList	Dynamic arrays using java.util.ArrayList
ArrayProblems	Array-based problem solving
SortingAlgorithm	Bubble, Selection, Insertion, Merge, Quick Sort
SearchingAlgorithm	Linear Search, Binary Search
RecursionProblems	Recursive thinking and problem solving
LeetCodeProblems	Competitive programming practice problems
MaximumAndMinimumFinder	Array traversal and comparison logic
FactorialCalculator	Iterative and recursive factorial
FibonacciCalculator	Fibonacci with loops and recursion
FindingRootsOfEquation	Numerical methods (Bisection, Newton-Raphson)
FindingSystemTime	Benchmarking algorithms using system time
MiscellaneousProblem	Mixed logic and problem-solving exercises

---

🚀 Getting Started

Prerequisites

• Java JDK 17 or above
• Any IDE: IntelliJ IDEA, Eclipse, or VS Code with Java Extension

How to Run

Using Terminal / CMD:

# Navigate to any folder
cd SortingAlgorithm

# Compile the Java file
javac Main.java

# Run the program
java Main

Using IntelliJ IDEA:

1. Open the project folder
2. Right-click any .java file
3. Click Run

---

🧠 Key Concepts Practiced

OOP Pillars

• ✅ Encapsulation — Private fields with getters/setters
• ✅ Inheritance — Parent-child class relationships
• ✅ Polymorphism — Method overloading & overriding
• ✅ Abstraction — Abstract classes and interfaces

DSA Concepts

• ✅ Arrays & ArrayLists
• ✅ Recursion & Backtracking
• ✅ Sorting — Bubble, Merge, Quick, Selection, Insertion
• ✅ Searching — Linear, Binary
• ✅ String Manipulation
• ✅ Bit Manipulation
• ✅ File I/O
• ✅ Multithreading
• ✅ Networking (TCP/SMTP)

---

📈 Learning Roadmap

Beginner        →     Intermediate      →      Advanced
─────────────────────────────────────────────────────────
Variables            OOP Concepts             Multithreading
Arrays               Recursion                Networking
Strings              Sorting & Searching      LeetCode Problems
Functions            File Handling            DSA Deep Dive

---

🤝 Contributing

Feel free to fork this repository, add new problems or improve existing solutions, and submit a pull request!

---

👤 Author

Muhammad Abdullah

• Learning Java | OOP & DSA Enthusiast
• 📅 Started: November 2025
• 💼 LinkedIn
• 🐙 GitHub

---

📄 License

This project is open-source and available for educational purposes.

---

"The only way to learn programming is to write programs." — Dennis Ritchie