My website's content is xml, and I use Apache Fop to turn it into a PDF with page numbers and other nice things. It works nicely, but takes some setup.

This site has great tutorials for Java and Spring:

https://www.marcobehler.com/courses/spring-professional

Take him to a planetarium or dinosaur museum

#2 is interesting...can you give an example solving circular dependencies? Even if you had an interface, wouldn't you still have the implementations still causing a circular dependency?

You can turn A->B, B->A into A->I,B->A + A.I=B and that does avoid a circular dependency.

A->B means a depends on B, A->I means A depends on an interface, and A.I=B means that B is set as the implementation of the I interface that A depends on.

I’m on mobile so that was the best I could come up with. Try it out using Swift though, and that can be translated pretty directly.