The reactive programming model stands out among the most exciting feature of Spring 5.0. The Spring 5.0 Framework is based on a reactive foundation and is completely asynchronous and non-blocking. The new event-loop execution model can scale vertically using few threads.

The framework procures reactive streams to provide a system for conveying backpressure in a pipeline of reactive components. Backpressure is an idea that guarantees consumers do not get overpowered with data originating from different producers.

While Java 8 does not have built-in support for reactive programming, there are a number of frameworks that provide support for reactive programming:

• Reactive Streams: Language-neutral attempt to define reactive APIs
• Reactor: Java implementation of Reactive Streams provided by the Spring Pivotal team
• Spring WebFlux: Enables the development of web applications based on reactive programming; provides a programming model similar to Spring MVC