I cannot say that I'm an expert in DI. But I've done DI quite a lot using Spring. And for me concept of DI is quite straightforward and easy to understand.
Frameworks like Spring also make it easy to implement DI. So I'm wondering will people who are already familiar with DI get any benefits from reading Dependency Injection book?
SCJA 1.0, SCJP 1.4, SCWCD 1.4, SCBCD 1.3, SCJP 5.0, SCEA 5, SCBCD 5; OCUP - Fundamental, Intermediate and Advanced; IBM Certified Solution Designer - OOAD, vUML 2; SpringSource Certified Spring Professional
That's a fair question. As I said in another post elsewhere on this forum and the welcome thread, this is mainly a software engineering, design patterns and best practices book. The approach to designing applications and architecture is constrained through the lens of DI, using it as a tool to illustrate many common pitfalls and use cases. So really the book is more about architecture and the background is DI and examples using real world libraries and tools.
You may want to look at some of the sample chapters posted on the book's website to get a taste of how things are explained (for example, modularity, concurrency, lifecycle management and so on): http://manning.com/prasanna