ATM Banking System Simulation

This Java project simulates a basic banking system with an ATM, demonstrating concurrent transactions, thread synchronization, and basic banking operations like deposits, withdrawals, and interest calculation.

Features

• Concurrent Transactions: Supports multiple threads simulating users depositing and withdrawing money simultaneously.
• Thread Synchronization: Uses ReentrantLock and Condition to ensure that transactions are thread-safe and that withdrawals are blocked when there are insufficient funds.
• Logging: Tracks each transaction (deposit, withdrawal, interest addition) with timestamps and relevant details (thread name, amount, balance).
• Interest Calculation: A separate thread periodically adds interest to the account balance.
• Testable: Includes a comprehensive JUnit 5 test suite to verify the correctness of the banking operations under various scenarios, including concurrent access.

Project Structure

The project consists of the following classes:

• BankAccount: Represents the shared bank account. It handles deposits, withdrawals, interest calculations, and maintains the account balance. It uses synchronization mechanisms to ensure thread safety.
• DepositThread: Represents a thread that repeatedly deposits a fixed amount into the bank account at a specified interval.
• WithdrawThread: Represents a thread that repeatedly withdraws a fixed amount from the bank account at a specified interval. It handles waiting when there are insufficient funds.
• InterestThread: Represents a thread that periodically adds interest to the bank account balance.
• BankingSimulation: The main class that sets up the simulation, creates the bank account and threads, and starts the simulation.
• BankingSimulationTest: A JUnit 5 test suite that thoroughly tests the BankAccount class, including concurrent transaction scenarios.

Code Principles Followed

• DRY (Don't Repeat Yourself): Common logic is encapsulated in appropriate classes (e.g., transaction logic in DepositThread and WithdrawThread).
• KISS (Keep It Simple, Stupid): The code is designed to be straightforward and easy to understand.
• Single Responsibility Principle: Each class has a well-defined responsibility (e.g., BankAccount manages the account, DepositThread handles deposits).

Prerequisites

• Java Development Kit (JDK) 8 or higher.
• A Java IDE (e.g., IntelliJ IDEA, Eclipse) or a build tool like Maven or Gradle (optional, but recommended for dependency management).

How to Run

1. Clone the repository:

   git clone <https://github.com/heev7777/ATM-Withdraw-Threads.git>

2. Compile the code:

   • Using an IDE: Import the project into your IDE and build it.

3. Run the simulation:

   • Using an IDE: Locate the BankingSimulation class and run its main method.

4. Run the tests:

   • Using an IDE: Locate the BankingSimulationTest class, right-click, and select "Run 'BankingSimulationTest'".

Output

When you run the BankingSimulation, you will see output similar to this in the console:

2025-02-03 12:01:10 - pool-1-thread-1 deposited $300.0. New balance: $1300.0
2025-02-03 12:01:10 - pool-1-thread-2 withdrew $200.0. New balance: $1100.0
2025-02-03 12:01:11 - pool-1-thread-1 deposited $300.0. New balance: $1400.0
2025-02-03 12:01:12 - pool-1-thread-2 withdrew $200.0. New balance: $1200.0
2025-02-03 12:01:12 - pool-1-thread-1 deposited $300.0. New balance: $1500.0
2025-02-03 12:01:13 - pool-1-thread-1 deposited $300.0. New balance: $1800.0
2025-02-03 12:01:14 - pool-1-thread-2 withdrew $200.0. New balance: $1600.0
2025-02-03 12:01:14 - pool-1-thread-1 deposited $300.0. New balance: $1900.0
2025-02-03 12:01:15 - pool-1-thread-1 deposited $300.0. New balance: $2200.0
2025-02-03 12:01:16 - pool-1-thread-2 withdrew $200.0. New balance: $2000.0
2025-02-03 12:01:16 - pool-1-thread-1 deposited $300.0. New balance: $2300.0
2025-02-03 12:01:17 - pool-1-thread-1 deposited $300.0. New balance: $2600.0
2025-02-03 12:01:18 - pool-1-thread-2 withdrew $200.0. New balance: $2400.0
2025-02-03 12:01:18 - pool-1-thread-1 deposited $300.0. New balance: $2700.0