Hi Martin,
Good question.
The Map<String,String> example was just a simple Spring Boot demonstration and
not intended to represent anything related to XSLT or result documents. It was
included to demonstrate how an endpoint works and how a request maps to a
response.
That said, your question made me realize my example could be misleading in
this context. Ibve updated the example so that it returns XML instead, which
is more consistent with the rest of the paper. The revised version is:
@GetMapping("/hello")
public String hello() {
    return "<message>Spring Boot is working!</message>";
}
Thanks for pointing that outbitbs a helpful improvement.
Regarding your suggestion about hosting the guides online: thatbs a good
idea. For now, Ibve just been sharing them directly with anyone whobs
interested. I donbt currently have a place set up to publish them, and
Ibve been trying to keep things simple and focused on the writing itself.
Best,
Roger