You're probably right about Spring Boot. I've never been a web developer, and TBH, I've had no direct experience with either Boot or DW other than a simple Hello, World. At the time DW seemed the safer choice simply because it used the JAX-RS standards, and using standards in the Java world (especially good ones like JAX-RS) is a very good idea. But in the meantime Spring Boot has also done the right thing and adopted JAX-RS (at least as an alternate API), so I should add it to the post.

As to Maven vs. Gradle, that turned out to be the most controversial point of the entire guide -- which surprised me. Let me put it this way: both are good and I prefer Gradle. Also, Gradle, while still far behind Maven in terms of adoption, has good momentum. Either is a good choice at this moment, but I would guess that Gradle will take the lead in five years (although it's far from a safe bet).