Building microservices from a monolith

One common question that I have already heard dozens of times is, "how do I break down my monolith into microservices?", or, "how do I migrate from a monolith approach to microservices?"

Well, that's what this recipe is all about.

Getting ready

For both monolith and microservice projects, we will use the same dependency:

        <dependency>
            <groupId>javax</groupId>
            <artifactId>javaee-api</artifactId>
            <version>8.0</version>
            <scope>provided</scope>
        </dependency>

How to do it...

Let's begin by building a monolith to split into microservices.

Building a monolith

First, we need the entities that will represent the data kept by the application.

Here is the User entity:

@Entity
public class User implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long...