Executors

29 Sep 2023

In Java, the java.util.concurrent package provides us with a powerful feature called Executors to handle parallel execution of tasks. It abstracts the complexities of managing threads and allows us to focus on writing efficient and scalable code.

What is Executors?

Executors is a utility class that provides several factory methods to create different types of thread pools. It simplifies the process of creating and managing threads, allowing us to concentrate on the business logic of our application rather than low-level thread management.

Using Executors, we can easily create thread pools of fixed size, cached threads, scheduled threads, and more.

Types of Executors

FixedThreadPool: This executor maintains a fixed number of threads. Tasks are submitted to the pool and executed as soon as a thread becomes available. If all threads are busy, tasks are queued waiting for a thread to become available.
```
ExecutorService executor = Executors.newFixedThreadPool(5);
```
CachedThreadPool: This executor is useful when the number of threads can vary as per the concurrent workload. If a thread is available, it will be reused. If no threads are available, a new one will be created. Threads that remain idle for a certain period of time (60 seconds by default) are terminated and removed from the pool.
```
ExecutorService executor = Executors.newCachedThreadPool();
```
SingleThreadExecutor: This executor maintains a single thread to execute tasks sequentially. If a task is submitted while another is still running, it will be queued and executed only after the current task completes.
```
ExecutorService executor = Executors.newSingleThreadExecutor();
```
ScheduledThreadPool: This executor supports delayed execution and task scheduling. It can schedule tasks to be executed after a certain delay or periodically at fixed intervals.
```
ScheduledExecutorService executor = Executors.newScheduledThreadPool(3);
```

Conclusion

Utilizing Executors in Java allows us to manage concurrent execution efficiently. By choosing the appropriate type of executor, we can optimize the utilization of system resources and improve the performance of our applications.

#Java #Concurrency