Java Invoice Management System

A lightweight, object-oriented invoice management application built in Java. This project demonstrates class design, encapsulation, and simple I/O-based reporting for managing clients, users, and billing line items.

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🧠 Key Skills Demonstrated

• Object-Oriented Programming (OOP): Encapsulation, modular class design (User, Client, Invoice, etc.)
• File and Report Generation: Structured invoice reporting with Report.java
• Data Modeling: Clear separation of responsibilities through specialized classes
• Code Readability & Maintainability: Logical organization and straightforward method structure
• Practical Use Case Implementation: Simulates a real-world business process (client billing)

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🧱 Tech Stack

• Language: Java SE
• Structure: Single-package class-based architecture
• Run Environment: Terminal or IDE (Eclipse, IntelliJ)
• Input Format: Hardcoded or test-structured objects
• Output: Invoice reports via console or file

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🗂️ Project Structure

INVOICE/ ├── src/ │ ├── User.java → Represents a system user or employee │ ├── Client.java → Represents a client/customer │ ├── Invoice.java → Core invoice details (client, items, totals) │ ├── LIneItem.java → Billing line items (description, price, quantity) │ ├── Report.java → Report generator │ └── Class.java → Main entry point (can be renamed to Main.java)

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🚀 How to Run

Option 1: In an IDE

1. Open the INVOICE/src/ folder in Eclipse or IntelliJ
2. Rename Class.java to Main.java (recommended for clarity)
3. Run the Main.java file

Option 2: From Terminal

cd INVOICE/src
javac *.java
java Class