Java Point-of-Sale System (POS)

A fully functional, modular Point-of-Sale (POS) application developed in Java, showcasing practical implementation of object-oriented principles, GUI development, and data-driven transaction processing. Designed to simulate real-world retail operations including item management, payment processing, and session handling.

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🧠 Key Skills Demonstrated

• Object-Oriented Design (OOP): Inheritance, abstraction, composition, aggregation, interfaces
• Java GUI (Swing): Form-based input, panels, event handling with ActionListeners
• File I/O and Data Parsing: CSV ingestion with error-handling and structured memory loading
• Design Patterns: Modular MVC-style separation across PD, DM, and UI packages
• Unit Testing: Functional and data-layer testing with robust test classes
• Business Logic Modeling: Cash, check, and credit payment types; tax calculation; price promotions

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🧱 Tech Stack

• Language: Java SE
• GUI: Java Swing
• Testing: JUnit-style unit tests
• Build Tools: Manual via IDE or terminal
• Date Utility: LGoodDatePicker JAR (for GUI date input)
• Data Format: CSV

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🗂️ Project Structure Overview

src/ ├── POSPD/ → Domain models (Item, Sale, Cashier, Payment, Tax) ├── POSDM/ → Data management (CSV parser, in-memory store) ├── POSUI/ → Full-featured GUI with real-time interaction ├── POSTests/ → Functional and integration test suites

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🚀 How to Run

Option 1: Using Eclipse or IntelliJ

1. Open the POS folder as a Java project
2. Add LGoodDatePicker-10.4.1.jar to the classpath
3. Run Start.java inside POSUI

Option 2: Terminal

cd POS/src
javac -cp .;../LGoodDatePicker-10.4.1.jar POSUI/Start.java
java -cp .;../LGoodDatePicker-10.4.1.jar POSUI.Start