Reactive Java EE monolith

Java EE doesn't include reactive paradigms in its specifications. The reason is simple—it was born before the ability to design architecture in this way was developed. For this reason, it's not very easy to make Java EE reactive.

Despite this, the latest Java EE releases introduced, and subsequently improved, one of the key features of the Reactive Stream specifications—asynchronicity.

So if you don't want to rewrite your application using one of the frameworks we described earlier, or other options such as Akka, you could try revisiting your Java EE classic implementation to make it reactive-oriented.

Java EE has the following two main aspects that could be useful for this topic:

•  The ability to process requests in asynchronously 
•  The ability to decouple communications between its components via messages

Let's examine these features in more detail.