Multi-Threading in Spring Boot using CompletableFuture

Swathi Prasad
6 min readSep 15, 2019

Multi-threading is similar to multitasking, but enables the processing of executing multiple threads simultaneously, rather than multiple processes. The CompletableFuture, was introduced in Java 8, provides an easy way to write asynchronous, non-blocking and multi-threaded code.

Spring Boot and Multi-threading

The Future interface which was introduced in Java 5, to handle asynchronous computations. But, this interface did not have any methods to combine multiple asynchronous computations and handle all the possible errors. The CompletableFuture implements Future interface, it can combine multiple asynchronous computations, handle possible errors and offers much more capabilities.

Let’s get down to writing some code and see the benefits.

Create a sample Spring Boot project and add the following dependencies.

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns=""
<relativePath />
Swathi Prasad

Software architect and developer living in Germany. Sharing my opinion and what I learn.