Putting in Reactive fashion

We have been creating an amazing application with Spring Boot. The application was built on the traditional web stack present on Spring Framework. It means the application uses the web servers based on Servlet APIs. 

The servlet specification was built with the blocking semantics or one-request-per-thread model. Sometimes, we need to change the application architecture because of non-functional requirements. For example, if the application was bought by a huge company, and that company wanted to create a plan to launch the application for the entire world, the volume of requests would probably increase a lot. So, we need to change the architecture to adapt the application structure for cloud environments.

Usually, in a cloud environment, the machines are smaller than traditional data centers. Instead of a big machine, it is popular to use many...