Let's move on to the implementation of the application boundaries with Java EE. This is, in fact, a more system-architectural question than an implementational one.

Communication between microservices should use technology-agnostic protocols. As seen previously, Java EE heavily supports HTTP, for both HTTP and REST services use Hypermedia.

The next sub-chapter will cover asynchronous communication in CQRS systems, using publish/subscribe messaging implemented with Apache Kafka.