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This repository chronicles my 100-day journey mastering Java programming from absolute basics to advanced concepts. Every line of code represents dedication, growth, and the pursuit of becoming a skilled Software Development Engineer.
📋 Table of Contents
- 📝 Variables & Data Types
- 🔄 Control Structures
- 🧩 Method Mastery
- 🗃️ Arrays & Collections
- 🏗️ Classes & Objects
- 🧬 Inheritance & Polymorphism
- 🛡️ Encapsulation
- 🧱 Abstraction
⚠️ Exception Handling- 📦 Package Management
- 🔗 Lambda Expressions
- 🧬 Generics
| Project | Description | Concepts |
|---|---|---|
| 🎲 Quiz Game | Interactive console application | Control Flow, Collections |
| 📊 Grade Manager | Student management system | OOP, File I/O |
| 🧮 Calculator | Mathematical operations | Methods, Exception Handling |
| 🏦 Bank Simulator | Real-world application | Advanced OOP, Design Patterns |
🔥 Click to explore all 50+ concepts mastered
journey
title Java Learning Journey
section Fundamentals
Hello World : 5: Day 1
Variables : 4: Day 5
Control Flow : 3: Day 10
Arrays : 4: Day 15
section OOP
Classes : 5: Day 25
Inheritance : 4: Day 35
Polymorphism : 5: Day 45
section Advanced
Exceptions : 4: Day 65
Generics : 5: Day 80
Lambda : 5: Day 95
- ✅ Variables & Data Types (Primitive & Reference)
- ✅ Operators (Arithmetic, Logical, Bitwise)
- ✅ Input/Output Operations
- ✅ Control Flow (if-else, switch, loops)
- ✅ Methods & Parameter passing
- ✅ Arrays (1D, 2D, Jagged)
- ✅ Object-Oriented Programming Fundamentals
- ✅ Classes & Objects
- ✅ Constructors & Method Overloading
- ✅ Inheritance & super keyword
- ✅ Polymorphism (Runtime & Compile-time)
- ✅ Abstract Classes & Interfaces
- ✅ Packages & Access Modifiers
- ✅ String Manipulation & StringBuilder
- ✅ Exception Handling & Custom Exceptions
- ✅ File I/O Operations
- ✅ Collections Framework Overview
- ✅ Generics & Type Safety
- ✅ Collections Framework (List, Set, Map)
- ✅ Lambda Expressions & Functional Interfaces
- ✅ Stream API & Method References
- ✅ Multithreading Basics
- ✅ Design Patterns (Singleton, Factory)
🔍 Click to explore the complete folder structure
📦 Java-Programs
├── 📁 01_Basic/ ← 🌟 Start Here!
│ └── 🧪 Practice-Set/
├── 📁 02_DataTypes/ ← 🎯 Primitives & Objects
├── 📁 03_Variables/ ← 🔄 Scope & Lifecycle
├── 📁 04_OperatorsAndExpressions/ ← ➕ Mathematical Operations
│ └── 🧠 PracticeProblem/
├── 📁 05_ControlStatement/ ← 🎮 Logic & Flow Control
│ └── 🎲 QuizGame/ ← Mini Project!
├── 📁 06_Methods/ ← 🔧 Reusable Code
│ └── 📊 Practice_Project/ ← Grade Manager
├── 📁 07_ArrayAndString/ ← 📝 Data Structures
├── 📁 08_OOPs/ ← 🏗️ Object-Oriented Basics
│ ├── 🧱 Abstraction/
│ ├── 🛡️ Encapsulation/
│ └── 🚗 Inheritance/
├── 📁 09_ArrayAndString/ ← 📋 Advanced Collections
│ └── 📋 ArrayList/
├── 📁 10_String/ ← 🧵 Text Processing
├── 📁 11_OOPs/ ← 🧬 Advanced OOP
│ ├── 👨👩👧 inheritance/
│ ├── 🧠 OOPs1/
│ ├── 🧬 OOPs2/
│ └── 🧪 OOPs3/
├── 📁 Exception_Handling/ ← ⚠️ Error Management
├── 📁 LambdaExpression/ ← 🔗 Functional Programming
├── 📁 OOPs/Generics/ ← 🧬 Type Safety
└── 📁 SelfQuestions/ ← 🧠 Challenge Yourself!
└── 🧪 01_BasicQuestions/
💡 Pro Tips & Advanced Commands
Single File Programs:
javac FileName.java && java FileNamePackage-based Programs:
# Compile from root directory javac -d . package/path/ClassName.java # Run with full package name java package.path.ClassName
Multiple Classes:
# Compile all files in directory javac *.java # Run the main class java MainClassName
# Quick compilation for current directory find . -name "*.java" -exec javac {} + # Run with custom classpath java -cp . com.example.MainClass # Debug mode java -Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=5005 MainClass
🧠 Technical Skills:
- Problem-solving mindset
- Clean code practices
- Debugging expertise
- Design pattern recognition
🎯 Soft Skills:
- Persistence and consistency
- Self-directed learning
- Documentation importance
- Community engagement
| 🎯 Milestone | 📅 Day | 💭 Reflection |
|---|---|---|
| ✅ First "Hello World" | Day 1 | The beginning of everything |
| ✅ First working loop | Day 8 | Understanding iteration |
| ✅ First custom class | Day 25 | OOP breakthrough moment |
| ✅ First inheritance | Day 35 | Code reusability unlocked |
| ✅ Exception handling | Day 55 | Writing robust code |
| ✅ Lambda expressions | Day 85 | Modern Java mastery |
| ✅ 100th program | Day 100 | Mission Accomplished! |
🌟 Standout Programs & Projects
- Features: Multiple choice questions, scoring system, difficulty levels
- Concepts: Control flow, collections, user input validation
- Lines: 200+ lines of well-structured code
- Features: CRUD operations, file persistence, grade calculations
- Concepts: OOP design, file I/O, exception handling
- Lines: 300+ lines with comprehensive error handling
- Features: Scientific operations, expression parsing, history
- Concepts: Method overloading, static methods, string manipulation
- Lines: 250+ lines with modular design
- Features: Multiple account types, transactions, interest calculation
- Concepts: Inheritance, polymorphism, encapsulation
- Lines: 400+ lines demonstrating real-world OOP
Having mastered the fundamentals, it's time to dive into enterprise-level Java development! The journey doesn't stop here—it evolves.
What's Next:
- 🌐 Web Development with Spring Framework
- 🗄️ Database Integration with Hibernate & JPA
- 🔗 RESTful APIs and Microservices
- 🧪 Testing with JUnit & Mockito
- 🏗️ Enterprise Patterns and Architecture
- ☁️ Cloud Deployment and DevOps
🚀 Explore Advanced Concepts:
- Spring Boot Applications
- RESTful Web Services
- Database Operations
- Security Implementation
- Testing Frameworks
📚 Core Java (✅ COMPLETED)
↓
🌐 Advanced Java (🚀 IN PROGRESS)
↓
☁️ Full Stack Development (🔜 COMING SOON)
- Start with Basics - Follow numbered folders sequentially
- Practice Along - Don't just read, code along!
- Modify & Experiment - Change code and observe results
- Challenge Yourself - Solve problems before looking at solutions
- 🐛 Found a bug? Open an issue with details
- 💡 Have a better solution? Submit a pull request
- 📝 Want to add documentation? We'd love that!
- ⭐ Found it helpful? Give it a star!