- Java Brains – Hibernate, Spring, Java EE, Struts 2, Maven, Servlets&JSPs
- Tutorials by Artur Owczarek – Hibernate, JPA, Spring (polish)
- Spring Boot Reference Guide
- Spring Boot Tutorial
- Official Spring Guides
- Spring by John Purcell – quite old, but you can try it too 🙂
- Java EE
- Java 8 Tutorial
- Gradle Docs
- Guava Tutorial and here
- Grails Tutorial + and this one(never tried it, but looks ok 😉 )
- Book: Spring in Action