Before learning Spring framework learn basics of Interfaces, XML and Annotations.
Docs:
- https://spring.io/projects (Spring projects)
- https://www.baeldung.com/ (Huge amont of small arcticles with working examples)
Where to learn (Spring core):
- A great playlist from YouTube: https://www.youtube.com/playlist?list=PLAma_mKffTOR5o0WNHnY0mTjKxnCgSXrZ (lesson 1 - 8).
- Spring in Action (Book) - best choise used to be version 4, now 5 is avalible, but is more complex.
But this is just start to a new world :)
What to learn later:
- Spring Boot
- Spring MVC
- Hibernate
- Spring Data
- Patterns
- SQL and NoSQL