In Chapter 7, Microservice Patterns, we explored the reactive programming paradigm and how it is implemented using Java EE 8 mechanisms. We also demonstrated how we can make asynchronous calls using Java EE 8 mechanisms, and how to control these calls and apply actions to them via asynchronous processing.
Event in CDI is a mechanism of the CDI specification that can be used in all tiers of an application. However, using this mechanism is recommended when working with a presentation tier. This is because CDI has a major focus on the presentation tier and its scopes are directly related to the HTTP interaction and HTTP session. Furthermore, we could launch an event with various elements that react to this event.
The asynchronous EJB method doesn't use the reactive programming paradigm but is an asynchronous process that makes it possible to decrease the time it takes to respond to the client. This is an EJB mechanism and it is recommended to use it at the business tier. The benefit...