RETAIL POS SYSTEM - CONSOLE APPLICATION

Complete Java Project with File Handling (No GUI, No Database)

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PROJECT OVERVIEW

This is a Console-Based Retail Point of Sale (POS) System developed using Core Java with Text File Storage for data persistence. The project demonstrates comprehensive use of Object-Oriented Programming concepts, File Handling, Exception Handling, and modular design.

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TEAM STRUCTURE

This project is designed for a team of 4 members, with each member responsible for specific packages and modules:

Person 1 - Main Application & User Module

• Package: com.retailpos.main
• Files: MainApp.java
• Responsibilities:
  • Menu-driven application interface
  • User authentication system
  • Main program flow control
  • Integration of all modules

Person 2 - Model Classes (OOP Design)

• Package: com.retailpos.model
• Files: Product.java, Customer.java, Bill.java
• Responsibilities:
  • Entity class design
  • Encapsulation implementation
  • Data modeling
  • Inner class implementation (BillItem)

Person 3 - Business Logic Services

• Package: com.retailpos.service
• Files: InventoryService.java, BillingService.java
• Responsibilities:
  • Inventory management logic
  • Billing operations
  • Customer management
  • CRUD operations
  • Report generation

Person 4 - File Handling & Exception Handling

• Package: com.retailpos.util & com.retailpos.exception
• Files:
  • FileUtil.java, ValidationUtil.java
  • ProductNotFoundException.java, InsufficientStockException.java,
  • InvalidInputException.java, AuthenticationException.java
• Responsibilities:
  • File I/O operations
  • Data validation
  • Custom exception classes
  • Error handling utilities

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PACKAGE STRUCTURE

com.retailpos
├── main
│   └── MainApp.java                    (Suraj Arya)
├── model
│   ├── Product.java                    (Aryan Pandey)
│   ├── Customer.java                   (Aryan Pandey)
│   └── Bill.java                       (Aryan Pandey)
├── service
│   ├── InventoryService.java           (Vaibhavi Anand)
│   └── BillingService.java             (Vaibhavi Anand)
├── util
│   ├── FileUtil.java                   (Atul Mishra)
│   └── ValidationUtil.java             (Atul Mishra)
└── exception
    ├── ProductNotFoundException.java   (Atul Mishra)
    ├── InsufficientStockException.java (Atul Mishra)
    ├── InvalidInputException.java      (Atul Mishra)
    └── AuthenticationException.java    (Atul Mishra)

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FILE STORAGE STRUCTURE

data/
├── products.txt      - Product inventory data
├── customers.txt     - Customer information
├── bills.txt         - Generated bills/invoices
└── users.txt         - Login credentials

File Formats:

products.txt:

ProductID|ProductName|Category|Price|StockQuantity|Description
P001|Laptop|Electronics|45000.00|15|Dell Inspiron 15 3000 Series

customers.txt:

CustomerID|CustomerName|PhoneNumber|Email|TotalPurchaseAmount
C001|Rahul Sharma|9876543210|rahul.sharma@email.com|0.0

users.txt:

Username|Password|Role
admin|admin123|ADMIN
cashier|cash123|CASHIER

bills.txt:

BillID|CustomerID|CustomerName|CashierName|BillDate|Subtotal|GST|TotalAmount|Items
B0001|C001|Rahul Sharma|admin|01-01-2026 10:30:00|45000.00|8100.00|53100.00|P001:Laptop:1:45000.00

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JAVA CONCEPTS IMPLEMENTED

1. Object-Oriented Programming (OOP)

• Encapsulation: All model classes with private fields and public getters/setters
• Inheritance: Exception classes extending base Exception class
• Polymorphism: Method overloading in constructors and utilities
• Abstraction: Service layer abstracting business logic

2. File Handling

• FileReader / FileWriter
• BufferedReader / BufferedWriter
• Try-Catch-Finally blocks
• File existence checking
• Directory creation

3. Collections Framework

• ArrayList for dynamic lists
• HashMap for key-value storage
• Iterating collections

4. Exception Handling

• Custom exception classes
• Try-Catch blocks
• Exception propagation
• Meaningful error messages

5. Advanced Concepts

• Inner classes (BillItem inside Bill)
• Static methods and constants
• String parsing and tokenization
• Date/Time handling
• Wrapper classes (Integer, Double)
• Input validation

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SYSTEM FEATURES

1. User Authentication

• Login system with username and password
• Role-based access (Admin/Cashier)
• Maximum 3 login attempts
• Credentials stored in users.txt

2. Product Management

• Add new products
• View all products
• Search products by ID/Name/Category
• Update product details
• Delete products
• Auto-generated Product IDs

3. Inventory Management

• Check stock availability
• Add stock to products
• Low stock alerts (stock < 10)
• Calculate total inventory value
• Stock reduction after billing

4. Billing System

• Create new bills
• Add multiple products to bill
• Calculate subtotal, GST (18%), and total
• Generate and display invoice
• Save bills to file
• Search bills

5. Customer Management

• Add new customers
• View all customers
• Search customers
• Track purchase history
• Auto-generated Customer IDs

6. Reports

• Sales report (total sales, GST, items sold)
• Inventory report
• Customer report

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HOW TO RUN

Method 1: Using Scripts (Linux/Mac)

1. Compile the project:

   chmod +x compile.sh
   ./compile.sh

2. Run the application:

   chmod +x run.sh
   ./run.sh

Method 2: Manual Compilation

1. Compile all files:

   javac -d bin -sourcepath src src/com/retailpos/exception/*.java
   javac -d bin -sourcepath src src/com/retailpos/util/*.java
   javac -d bin -sourcepath src src/com/retailpos/model/*.java
   javac -d bin -sourcepath src src/com/retailpos/service/*.java
   javac -d bin -sourcepath src src/com/retailpos/main/*.java

2. Run the application:

   cd bin
   java com.retailpos.main.MainApp

Method 3: Using IDE

1. Import the project into Eclipse/IntelliJ/NetBeans
2. Set src as source folder
3. Run MainApp.java

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DEFAULT LOGIN CREDENTIALS

Username	Password	Role
admin	admin123	ADMIN
cashier	cash123	CASHIER
manager	manager123	MANAGER

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SAMPLE WORKFLOW

Adding a Product:

1. Login as admin
2. Select Product Management → Add New Product
3. Enter product details
4. Product saved to products.txt

Creating a Bill:

1. Login as cashier
2. Select Billing System → Create New Bill
3. Enter Customer ID
4. Add products with quantities
5. Confirm billing
6. Invoice generated and saved
7. Stock automatically reduced

Checking Low Stock:

1. Select Inventory Management → Low Stock Alert
2. View products with stock < 10
3. Add stock as needed

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CODE QUALITY FEATURES

• Proper Comments: Every class and method documented
• Developer Attribution: Each file has developer name and responsibility
• Modular Design: Clear separation of concerns
• Error Handling: Comprehensive exception handling
• Input Validation: All user inputs validated
• Clean Code: Proper naming conventions and formatting
• Resource Management: Proper closing of file streams

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LEARNING OUTCOMES

Students working on this project will learn:

1. Core Java Concepts:

   • OOP principles
   • File handling with text files
   • Exception handling
   • Collections framework

2. Software Design:

   • Package organization
   • Layered architecture
   • Separation of concerns
   • Modular programming

3. Real-World Skills:

   • Team collaboration
   • Code documentation
   • Error handling strategies
   • Data validation

4. Problem Solving:

   • Inventory management logic
   • Billing calculations
   • Search and filter operations
   • Report generation

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TROUBLESHOOTING

Issue: Files not found

• Ensure data directory exists in project root
• Check file paths in FileUtil.java

Issue: Compilation errors

• Verify Java version (Java 8 or higher)
• Check CLASSPATH settings
• Ensure all files are in correct packages

Issue: Login failed

• Check users.txt file exists
• Verify credentials format in file

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IMPORTANT NOTES

1. No GUI: This is a console-based application
2. No Database: All data stored in text files
3. Text Files Only: Uses .txt files for storage
4. File Handling: Proper exception handling for file operations
5. Data Persistence: Data saved immediately after operations
6. GST Calculation: Fixed at 18% for all products

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PROJECT SUBMISSION CHECKLIST

• All Java files with proper package structure
• Developer name mentioned in each file
• Sample data files (products.txt, customers.txt, users.txt)
• Compilation scripts
• README documentation
• Code compiles without errors
• Application runs successfully
• All features working as expected

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SUPPORT

For issues or questions:

1. Check the README carefully
2. Review code comments and JavaDoc
3. Verify file paths and permissions
4. Check Java version compatibility

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LICENSE

This project is created for educational purposes as part of a Core Java course assignment.

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Developed by Team of 4 Members (Suraj Arya, Aryan Pandey, Vabhavi Anand, Atul Mishra) Technology Stack: Core Java, File Handling, Console I/O Version: 1.0 Date: January 2026