Product Management System (Core Java)

A menu-driven, console-based Product Management System implemented in Core Java using HashMap.
This project demonstrates CRUD operations, exception handling, interface usage, and custom sorting (by name and price).
It also includes JUnit test cases for validating each operation.

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🚀 Features

• Add Product → Insert new products with unique IDs
• View Product by ID → Retrieve product details
• Update Product → Modify product name and price
• Delete Product → Remove product by ID
• Display All Products → Show all available products
• Sorting → Sort products by Name or Price (using Comparator)
• Exception Handling → Handles duplicate IDs, missing products, etc.
• Interface Usage → Follows abstraction via ProductOperations
• JUnit Test Cases → Covers all CRUD + sorting functionality

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🛠️ Tech Stack

• Java (Core Java, JDK 25)
• Collections API (HashMap, List, Comparator)
• JUnit 5 (Testing framework)

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📂 Project Structure

ProductManagementSystem/
│
├── src/main/java/com/example
│ ├── Product.java # Entity class
│ ├── ProductOperations.java # Interface for operations
│ ├── ProductService.java # Implementation using HashMap
│ └── Main.java # Menu-driven console client
│
├── test/
│ └── ProductServiceTest.java # JUnit test cases
│
├── README.md
└── .gitignore

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📖 Learning Outcomes

• Using HashMap for CRUD-based storage
• Implementing interfaces for abstraction
• Applying custom sorting with Comparator
• Handling exceptions effectively
• Writing JUnit tests for validation

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