🚗 Parking Lot System in Java

An advanced, console-based Parking Lot System built using Java and Object-Oriented Programming (OOP) principles.
This project simulates a real-world parking lot with time-based parking fees, different parking spot sizes, and fast vehicle lookup using HashMap.

Perfect for Java beginners → intermediate learners, college mini-projects, and interview preparation.

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✨ Features

✅ Park and remove vehicles
✅ Parking fee calculation based on parking duration
✅ Time tracking using LocalDateTime
✅ Supports different vehicle types (Bike, Car)
✅ Different parking spot sizes (SMALL, MEDIUM, LARGE)
✅ Automatic spot allocation based on vehicle size
✅ Fast O(1) vehicle lookup using HashMap
✅ Clean, scalable OOP design

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🧠 System Design (OOP)

Core Components

• Vehicle (Abstract Class)
• Car, Bike (Inheritance)
• ParkingSpot
• ParkingLot
• Enums for type safety
• Main (Driver class)

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🏗️ Class Diagram (Logical)

Vehicle (abstract)
├── Bike
└── Car

ParkingLot
├── List<ParkingSpot>
└── HashMap<VehicleNumber, ParkingSpot>

ParkingSpot
├── SpotSize
├── Vehicle
└── EntryTime

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📦 Technologies Used

• Java (JDK 8+)
• OOP Concepts
• Collections Framework
• Date & Time API

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🧩 Concepts Covered

• Abstraction
• Inheritance
• Polymorphism
• Encapsulation
• Enums
• HashMap
• Time-based calculations
• Real-world system design

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🚀 How It Works

1. Vehicle arrives at parking lot
2. System finds a suitable parking spot based on size
3. Entry time is recorded
4. Vehicle is stored in a HashMap for fast access
5. On exit:
   • Parking duration is calculated
   • Fee is generated
   • Spot is freed

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💰 Parking Fee Logic

• Minimum charge: 1 hour
• Fee calculation: Parking Fee = Hours Parked × Rate per Hour
• Uses Duration.between(entryTime, exitTime)

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▶️ How to Run

1. Clone the repository

git clone https://github.com/yogeshkumarsaini/parking-lot-system-java.git

2. Open in IDE (IntelliJ / Eclipse / VS Code)
3. Compile and run Main.java

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📂 Project Structure

src/
 ├── Bike.java
 ├── Car.java
 ├── Vehicle.java
 ├── ParkingSpot.java
 ├── ParkingLot.java
 ├── SpotSize.java
 ├── VehicleType.java
 └── Main.java

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🔮 Future Enhancements

• Multi-floor parking lot
• Dynamic pricing (weekend/night rates)
• Parking tickets
• Database integration
• REST API using Spring Boot
• Unit tests (JUnit)