This has been my experience too.

I constantly fear Spring Boot magically reconfiguring itself based on what it finds in the classpath, and half the codebase being annotations and import statements.

I've found the metaprogramming in Ruby much easier to understand and teach than Java's reflection and annotation processing.

I really gave Spring Boot a shot, it's just way above my head. Never felt like I had a good sense of knowing what the heck was going on what with all the Beans and annotations. But my Java was pretty poor - that could be the reason. However I never had this difficulty with Rails/Django/Node, they all felt pretty intuitive to me.

It's not your fault. Spring Boot is a trip to hell compared with Rails.

Perhaps I've only had to deal with sane Java codebases - I feel like magic is not the norm in Java.

Magic is built into the Ruby language, what with everything being "message passing" under the hood.