Java Practice Repository

Overview

This repository contains a comprehensive collection of Java programming exercises and assignments demonstrating various concepts from basic programming fundamentals to advanced object-oriented programming (OOP) concepts. The files are organized to showcase my learning journey in Java development.

Repository Structure

📁 Core Java Practice Files (Root Directory)

Basic Java programs demonstrating fundamental concepts:

Basic Programs

• Hello.java / InputExample.java - Basic input/output operations
• Calculator.java - Simple calculator with basic arithmetic operations
• Temperature.java - Temperature conversion (Celsius ↔ Fahrenheit)
• Table.java - Multiplication table generator
• SumOfNatural.java - Sum of first N natural numbers
• Factorial.java - Factorial calculation
• Marks.java - Grade calculation based on marks in DSA, OOP, and DBMS
• Counter.java - Even/odd number counter
• Password.java - Simple password guessing game
• GuessTheGame.java - Number guessing game with random number generation

Advanced Applications

• SimpleInterestCalculator.java - Multi-customer simple interest calculator
• BusTicket.java - Bus ticket booking system simulation
• Atm.java - Basic ATM withdrawal simulation
• Bill.java - Electricity bill calculator with tiered pricing

Object-Oriented Programming

• Animal.java - Basic class definition with constructor and methods
• AnimalDemo.java - Inheritance and polymorphism with Animal, Dog, and Cat classes
• Shape.java - Basic shape class with method definitions
• Geeks.java - Abstract classes and method overriding with geometric shapes
• Person.java - Base Person class for inheritance examples
• SingleInheritanceDemo.java - Student extends Person class demonstration
• LibraryDemo.java - Advanced inheritance with LibraryItem, Book, and Magazine classes
• Bank.java - Basic banking class structure

📁 Assignment Folder

Structured assignments demonstrating specific programming concepts:

Banking System (assignment/)

• Account.java - Complete banking account class with deposit, withdrawal, and contact management
• UserInterface.java - Console-based banking application with menu system

Assignment 2 (assignment2/)

Folder 1: Library Management System

• Book.java - Book class with encapsulation
• Library.java - Library management with ArrayList operations
• Main.java - Demonstration of library operations
• README.md - Detailed documentation

Folder 2: Student Management System

• Student.java - Student class with grades and GPA calculation
• Course.java - Course enrollment and management
• Main.java - Combined student and course management demo

Folder 3: Employee Management System

• Employee.java - Base employee class
• Manager.java - Manager class extending Employee with bonus
• Developer.java - Developer class extending Employee with overtime pay
• Department.java - Department management with salary calculations

📁 Additional Files

• staticArray.cpp - C++ example for comparison (dynamic vs static arrays)

Key Programming Concepts Demonstrated

🔸 Basic Programming

• Variables, data types, and operators
• Control structures (if-else, loops, switch)
• Scanner for user input
• Random number generation
• Mathematical calculations

🔸 Object-Oriented Programming

• Classes and Objects: Creating and using custom classes
• Encapsulation: Private variables with public getter/setter methods
• Inheritance: Single and multilevel inheritance examples
• Polymorphism: Method overriding and dynamic method dispatch
• Abstraction: Abstract classes and methods
• Constructors: Default and parameterized constructors

🔸 Data Structures

• Arrays and ArrayList operations
• HashMap for key-value storage
• Collection iteration and manipulation

🔸 Design Patterns and Best Practices

• Proper class design and separation of concerns
• User interface separation from business logic
• Input validation and error handling
• Code documentation and commenting

How to Run the Programs

Prerequisites

• Java Development Kit (JDK) 8 or higher
• Terminal/Command prompt access

Compilation and Execution

1. Single File Programs:

   javac ProgramName.java
   java ProgramName

2. Multi-Class Programs:

   javac *.java
   java MainClassName

3. Assignment Folders:

   cd assignment/
   javac *.java
   java UserInterface

Example Usage

# Run the calculator
javac Calculator.java
java Calculator

# Run the banking system
cd assignment/
javac *.java
java UserInterface

# Run the library management system
cd assignment2/1/
javac *.java
java Main

Sample Programs Output

Calculator Example

Enter the value 1: 10
Enter the value 2: 5
Enter the operator: +
Result: 15

Banking System Example

Welcome to the Banking Application!
1. Create a new account
2. Deposit money
3. Withdraw money
4. View account details
5. Update contact details
6. Exit
Enter your choice: 1
Enter account holder name: John Doe
Enter initial deposit amount: 1000.0
Enter email address: john@example.com
Enter phone number: 123-456-7890
Account created successfully with Account Number: 1001

Grade Calculator Example

Enter the marks of Subject DSA: 85
Enter the marks of Subject OOP: 90
Enter the marks of Subject DBMS: 88
Grade: A

Learning Outcomes

Through these exercises, I have practiced and demonstrated:

• Problem Solving: Breaking down complex problems into manageable components
• Code Organization: Structuring code for readability and maintainability
• User Experience: Creating intuitive console-based applications
• Error Handling: Implementing proper input validation and error management
• Documentation: Writing clear, comprehensive documentation

Technologies Used

• Language: Java (JDK 8+)
• IDE/Editor: VS Code
• Version Control: Git
• Documentation: Markdown

Projects Highlights

🏆 Banking Application

A complete console-based banking system featuring:

• Account creation and management
• Deposit and withdrawal operations
• Contact information updates
• Data validation and error handling

🏆 Library Management System

Object-oriented library system demonstrating:

• Book and Library class design
• ArrayList operations
• Encapsulation principles
• Clean code practices

🏆 Employee Management System

Inheritance-based system showcasing:

• Base Employee class with Manager and Developer extensions
• Polymorphic salary calculations
• Department-level aggregation and reporting

Future Enhancements

• Add GUI interfaces using Swing or JavaFX
• Implement file I/O operations for data persistence
• Add unit testing with JUnit
• Integrate database connectivity with JDBC
• Implement more advanced design patterns
• Add exception handling mechanisms
• Create web-based interfaces using Spring Boot

Repository Statistics

• Total Java Files: 40+
• Lines of Code: 2000+
• Concepts Covered: 15+
• Assignment Folders: 3
• Documentation Files: 2

Author

Varun Chauhan
Java Programming Practice Repository
Demonstrating fundamental to advanced Java concepts

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This repository represents my continuous learning journey in Java programming, from basic syntax to advanced object-oriented design principles. Each program is designed to reinforce specific concepts and build upon previous knowledge.