1. Introduction
In the world of Java concurrency, managing threads efficiently is paramount. This is where the Executor Service comes into play, offering a powerful framework for executing tasks asynchronously. In this article, we’ll delve into the Executor Service in Java, exploring its functionality, usage, and best practices.
2. Understanding Executor Service
At its core, the Executor Service provides a thread pool to manage and execute tasks concurrently. It abstracts away the complexities of thread management, allowing developers to focus on task execution logic rather than thread creation and management.
3. Creating an Executor
One of ways to do it is just calling a factory method like bellow. In this case we are creating an Executor with 10 threads.
4. Adding a task to an Executor
Runnable and Callable tasks. For the sake of simplicity in this article, we’ll utilize two basic tasks. It’s worth noting that we’ll employ lambda expressions instead of anonymous inner classes for clarity and brevity. 4.1 execute()
execute() method returns void, which means it doesn’t provide a way to obtain the result of a task’s execution or to check its status (whether it’s running or not). 
4.2 submit()
submit() submits a Callable or a Runnable task to an ExecutorService and returns a result of type Future. 
4.3 invokeAny()
invokeAny() assigns a collection of tasks to an ExecutorService, causing each to run, and returns the result of a successful execution of one task (if there was a successful execution).
4.3 invokeAll()
invokeAll() assigns a collection of tasks to an ExecutorService, causing each to run, and returns the result of all task executions in the form of a list of objects of type Future. 
5. Conclusion
In conclusion, the Executor Service is a versatile and powerful tool for managing concurrency in Java applications. By abstracting away the complexities of thread management, it simplifies the development of multithreaded applications while providing fine-grained control over task execution. By understanding its key components, usage patterns, and best practices, developers can leverage the Executor Service effectively to build robust and efficient concurrent systems.
