How do you create a CompletableFuture in Java?
Tale of Contents
Introduction
CompletableFuture
is a powerful class in Java introduced in Java 8 that simplifies asynchronous programming and allows you to write non-blocking code. It provides a way to represent a future result of an asynchronous computation, making it easier to manage tasks that run in the background.
Creating a CompletableFuture
1. Using the CompletableFuture.supplyAsync
Method
You can create a CompletableFuture
by using the supplyAsync
method, which executes a task asynchronously and provides the result.
Example:
2. Using the CompletableFuture.runAsync
Method
If you do not need a result and just want to execute a task asynchronously, you can use the runAsync
method.
Example:
Chaining CompletableFutures
You can chain multiple operations using methods like thenApply
, thenAccept
, and thenCombine
.
1. Using thenApply
This method allows you to transform the result of a CompletableFuture
.
Example:
2. Using thenCombine
You can combine the results of two CompletableFuture
instances.
Example:
Exception Handling
CompletableFuture
provides methods for handling exceptions, such as exceptionally
and handle
.
Example using **exceptionally**
:
Conclusion
Creating a CompletableFuture
in Java is straightforward and provides a robust way to handle asynchronous programming. With methods like supplyAsync
, runAsync
, and various chaining options, you can efficiently manage background tasks, combine results, and handle exceptions. By utilizing CompletableFuture
, you can write non-blocking code that enhances the responsiveness and performance of your applications.