ExecutorService

Manually creating and managing threads (`new Thread(...)`) can be inefficient. Creating a new thread is a relatively expensive operation, and having too many active threads can degrade performance due to the overhead of context switching. A more robust and efficient approach is to use a thread pool. A thread pool is a managed collection of reusable worker threads. The `ExecutorService` framework, part of the `java.util.concurrent` package, is Java's high-level API for managing thread pools. Instead of creating a thread for each task, you submit your tasks (as `Runnable` or `Callable` objects) to an `ExecutorService`. The service then assigns the task to one of the available threads in its pool. If all threads are busy, the task is placed in a queue to wait for a thread to become free. This model decouples task submission from task execution and handles all the low-level details of thread management for you. You can create different types of thread pools using factory methods in the `Executors` class. For example, `Executors.newFixedThreadPool(10)` creates a pool with a fixed number of 10 threads. `Executors.newCachedThreadPool()` creates a pool that can grow and shrink dynamically based on demand. Using an `ExecutorService` not only improves performance by reusing threads but also provides better control over resource consumption and makes your concurrency code cleaner and more manageable. It is the modern, recommended way to handle concurrent tasks in Java.