What are best learning resources for Java Spring boot Framework?

Question

I am principally on .Net Framework stack but recently, we have been moving our legacy applications from AS400 [RPG] to Front Angular and Backend Java Services written in Spring Boot MVC and interacting with DataStax and IBM's LUW.
I have been to canonical and some other places for Spring Boot but I have noticed most of them are not as up to date as they should be and there are huge changes in the way services/controllers/configurations can happen b/w versions.
Is there any good site for Spring Boot learning? If yes, please share.
Thanks!!!!

Answer 1

https://www.sololearn.com/Discuss/2062588/?ref=app

Answer 2

Thanks. I have been to them and tbh, they mostly are primitive [except spring.io and its code generator part]