Spring Cloud Stream can be treated as a separate category in comparison to all the other Spring Cloud projects. It is often being associated with other projects, and which are currently strongly promoted by Pivotal Spring Cloud Data Flow. That is a toolkit for building data integration and real-time data processing pipelines. However, it is a huge subject and rather a topic of discussion for a separate book.
More to the point, Spring Cloud Stream provides support for asynchronous messaging, which may be easily implemented using a Spring annotation style. I think that for some of you, that style of inter-service communication is not as obvious as the RESTful API model. Therefore, I have focused on showing you the examples of point-to-point and publish/subscribe communication using Spring Cloud Stream. I have also described the differences between those two styles...
