Years ago when I was investigating Spring and Java EE, I was taken aback by how much additional work was involved. Not only do some tutorials only show how to install through Java's dedicated IDE, but also deciding on which application server to use, which adds another layer of technical decisions and slows down the process of "quickly testing" frameworks.
If you were "deciding which application server to use", then that WAS "years ago" indeed! The paradigm shifted, from applications being deployed to a server such as Weblogic or Websphere, to applications bundling their own HTTP server like Node or Golang. This shift happened around 15 years ago. Modern Java development looks almost nothing like it did back in that era.
@SpringBootApplication was all you needed on top of a main class. The biggest issue is somewhere along the Spring -> Pivotal -> VMWare -> Spring hot potato, their tutorials and documentation fell off a cliff. Everything became “just use initializer…”
Javelin breaks free of that. Excellent stuff!