Servlet 3.0 Async Support in Spring and Performance Misconceptions

It is possible to improve the performance of application servers using Servlet 3.0 async, but is it necessary?

Before We Start

Spring makes it easy to write Java applications. With Spring Boot, it became even easier. Spring Boot allows us to quickly create Spring applications: build and run a Java application server with embedded Tomcat and your own controller in less than 5 minutes. Well, I admit I used Spring Initializer for that: