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.