References – Spring

Official documentation

Spring Core Spring Core 5.x

Spring Security Spring Security 5.x

Spring Data Spring Data 3.1.1

Spring Boot Spring Boot 2.7.x

Certification

spring-certified-developer-study-guide [git]

Top 5 Spring Professional Certification Exam Resources for Java Developers

ALL WHAT YOU NEED TO KNOW TO PASS VMWARE SPRING PROFESSIONAL CERTIFICATION

Top 5 Spring Certification Books and Courses

Spring Courses

Spring Academy

Courses Baeldung