External Documentation
From Salespoint 5
Java
Java 1.7 Javadoc
Spring MVC
Introduction to Spring Web MVC framework
Spring Expression Language (SpEL)
Spring Security 1
Spring Security 2
Spring 3 Javadoc
Spring Framework Reference Documentation
Validation
[1]
[2]
[3]
Thymeleaf
Thymeleaf
Thymeleaf - Spring Security 3 integration module
JPA
Introduction to the Java Persistence API
javax.persistence Javadoc
Wikibooks - Java Persistence
Google JPA tutorial
Joda Time
Joda Time - Java date and time API