Spring documentation is excellent. I had to learn Spring as a PHP developer, so I put the documentation onto a Kindle and read it. It's also versioned, so you don't need to read out of date versions:
https://docs.spring.io/spring-framework/docs/
> This is different to eg DropWizard where you actually boot the app (no different to how it does in a real env ie no "test application context") and make real http requests to it. (not some watered down fake Spring HTTP test requests)
Spring Boot allows you to write full application tests that will boot it up on a random port with the @SpringBootTest annotation, as is covered by the excellent documentation
https://spring.io/guides/gs/testing-web/
> Add in the horribly, horribly ingrained, unidiomatic ways people use Spring (eg sprinkling field autowiring all over the place instead of instead of using constructor injection)
You can use whichever.
> anyone who uses any other framework is just stubborn and wrong.
Not at all. Spring Boot is just a great solution, that's all. It's got strong support from a company, lots of documentation and first class support for testing. It also allows you to easily swap out different underlying technology, eg. you can switch from Jetty or Tomcat, Liquibase to Flyway.
It's a disservice to persuade businesses to use smaller projects that don't have a comparable level of support, or flexibility.