The fact that this is one of the top-ranking books on Amazon for Spring is indicative of a broader necrosis in Java-centric technical writing and (in my opinion) the failings of the technology as a whole. In this text we have what appears to be someone's lecture outlines from a CS class, with no explanation, error-ridden code, and no context. Even by following the code examples by rote one cannot drive any useful information from this text because it's never clear WHY things work the way it suggests they do. An example from near the beginning of the text:
"@Qualifier
This annotation can be applied to classes, methods, fields, constructors and parameters of a bean class to allow for great control in using the correct reference types. The following example demonstrates the use of the @Qualifier annotation. In this example, the @Qualifier annotation is applied to the member of a class."
Followed by a single code example of a partial class, wherein the @Qualifier annotation is tossed onto one of the class's members, with no explanation as to why or what the annotation is actually doing there. Horrendous.
This is a very poor book and I would strongly recommend avoiding it.