One of the main reasons why Spring 5.0's framework was created is to fully integrate functional programming when implementing the asynchronous web framework. The so-called functional web framework has a reactive core that has its own annotation, interfaces, and classes for handling requests. Thus, to fully understand reactive programming in Spring is to know the core platform of Java functional programming.
The main idea of functional programming is to build a set of definitions to evaluate computer instructions. Each definition is a concise, single, and atomic expression that calls another occurrence of expressions which, collectively, can give a simplified result. Although functional programming is an old programming methodology based on mathematical principles, it is now being integrated in Java for the purposes of creating a transition from an imperative...