This is the very simplest of Spring servers.

Simplest SimpleSimon server

to run from the project's directory:

$ mvn spring-boot:run

If ain't got Maven, well, figure that out.

And if it works, look at all those amazinly informative log messages!

And then... In another terminal....

$ curl localhost:8080

<h2>Simple Simon Says: Hello World.</h2>

and TaDa!!