Reactive Systems in Java

Chapter 2. Introduction to Quarkus

Before continuing with understanding Reactive, let’s take a few moments to learn more about Quarkus. So what is Quarkus?

Quarkus is a Kubernetes-native Java stack. It has been tailored for Kubernetes, containers, and the cloud, but works perfectly well on bare metal and virtual machines.¹ Quarkus applications require less memory and start faster than applications using traditional frameworks. They also have the capability to be compiled into native executables, which make them consume even less memory and start instantly.

One exciting, and central, aspect of Quarkus is the reactive engine. When running in containers or virtualized environments, a reactive engine is essential to reducing memory and CPU consumption. The engine makes any Quarkus application efficient while also enabling the creation of reactive applications and systems.

In this chapter, you will see the main characteristics of Quarkus and learn to create an application, deploy it to Kubernetes, and create native builds. In Chapter 6, we cover the reactive engine in detail and show how to develop on Quarkus with a unified reactive and imperative programming model.

Java on the Cloud

Java is now 25 years old! That’s hard to imagine sometimes. From the era of three-tier and client/server architecture, Java has evolved with many changes in architecture over the years. However, when a language is 25 years old, there will be pieces lingering that may not be suited to modern development. ...