Implement Thread-Pool Executor pattern

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Description

The Thread-Pool Executor is a concurrency design pattern that maintains a pool of worker threads to process tasks. Rather than creating a new thread each time a task is submitted, the pattern reuses existing threads in the pool. This leads to more efficient CPU usage, less overhead from thread creation/destruction, and improved overall application performance.

Key Elements

• Thread Pool: A fixed or dynamically sized set of threads that carry out tasks.
• Task Submission: Tasks (e.g., Runnable or Callable) are placed in a queue for execution.
• Executor / ExecutorService: Provides an interface for submitting tasks (execute, submit) and managing the pool (shutdown, etc.).
• Resource Management: Reusing threads reduces overhead and improves response time in high-load scenarios.

References

1. Java Documentation for ThreadPoolExecutor
2. Java Concurrency in Practice (Brian Goetz)
3. Java Design Patterns - Contribution Guidelines

Acceptance Criteria

• Create a new module or package named thread-pool-executor (or similar).
• Demonstrate how tasks can be submitted to an executor service and processed by a pool of threads.
• Provide a README (or .md file) explaining the pattern, including code examples, diagrams, or both.
• Ensure all code follows the repository’s style, naming conventions, and best practices.
• Include unit tests that confirm correct behavior under load (multiple tasks) and confirm proper shutdown.
• Pass all continuous integration checks and meet the project’s contribution guidelines.