The client-server architecture is one of the most common architectural styles applied today, and it has been used in many different ways.

When we hear the term client-server architecture, we often think of old applications that provide a UI for editing complex databases in which the major part of the business logic resides. However, the truth is that this architectural style offers underlying support for almost every single modern architectural style, including microservices, event-driven architectures, or any distributed computing system.

In this chapter, we will review how the client-server architecture works, as well as how it can be implemented. We will use the Spring Framework to build the server side, and then we'll code clients interacting with the server using Java.

This chapter will cover the following points:

• Understanding client-server architectures
• Where to apply client-server architectures
• Implementing client-server architectures: 
  • Writing a server with Spring
  • Introducing Spring actuator
  • Monitoring the health of an application
  • Writing clients with Java FX and Android
• Testing the implemented code