POS System — Java Swing

A full-featured Point of Sale system built with Java Swing following OOP principles.

Architecture

com.pos/
├── Main.java                  ← Entry point
├── model/                     ← POJOs (User, Product, Order, etc.)
├── dao/                       ← JDBC data access (ProductDAO, OrderDAO, etc.)
├── service/                   ← Business logic (OrderService, StockService, etc.)
├── ui/
│   ├── MainFrame.java         ← Main window with sidebar navigation
│   ├── panels/                ← SalesPanel, ProductPanel, StockPanel, OrderPanel, etc.
│   ├── dialogs/               ← LoginDialog, PaymentDialog
│   └── components/            ← RoundedButton, StyledTable, UIConstants
└── util/                      ← DatabaseConnection, PasswordUtils, AppContext

Features

Panel	Features
Sales	Barcode scanning, product search, cart management, discount application, cash/card/QR payment
Products	CRUD with category & supplier, barcode, cost/selling price, status
Stock	Stock-in, adjustments, low-stock alerts (highlighted red), history log
Orders	Date-range filter, order detail view, total revenue summary
Users	Admin-only: create/edit/delete users, change passwords, role assignment
Settings	Store name, phone, address, currency, tax %

Prerequisites

• Java 17+
• Maven 3.8+
• MySQL 8.0+

Setup

1. Create database

cd pos_db

docker compose up

2. Run schema

mysql -u admin -p mydb < init.sql

3. Seed initial data

mysql -u admin -p mydb < src/main/resources/seed.sql

4. Configure database connection

Edit src/main/resources/application.properties:

db.url=jdbc:mysql://localhost:3306/mydb?useSSL=false&serverTimezone=UTC&allowPublicKeyRetrieval=true
db.username=root
db.password=your_password

5. Build and run

mvn clean package -q
java -jar target/pos-system-1.0.0-jar-with-dependencies.jar

Or run directly in your IDE by running com.pos.Main.

Default Login Credentials

Role	Username	Password
Admin	admin	admin123
Cashier	cashier	cashier123

Change passwords after first login!

OOP Design Highlights

• Layered architecture: UI → Service → DAO → Model — no layer skips
• Single responsibility: each class has one job (e.g. OrderDAO only handles DB, OrderService handles business rules)
• Encapsulation: all model fields are private with getters/setters
• Connection pooling: HikariCP manages DB connections efficiently
• Transaction safety: OrderDAO.save() uses a single transaction for order + items + payment + stock deduction
• Enum-like constants: RoundedButton.Style, Payment.Method, StockHistory.Type
• Renderer pattern: ProductCellRenderer in SalesPanel shows rich list items

Dependencies

Library	Purpose
mysql-connector-j	MySQL JDBC driver
HikariCP	High-performance connection pool
FlatLaf	Modern flat look-and-feel for Swing
jbcrypt	Secure password hashing
slf4j-simple	Logging