I took some time to read this book and I do not think I lost my so "precious" time. I would say that the book is not intended for Java beginners but more for people with a good technical background and especially with at least, some knowledge of the Java Enterprise world. Never the less, if you are not a specialist, just like I am not one, you could still read the book and you could learn a lot of new stuff.
Indeed, the book is taking you from the beginning and tries to lead you through different technologies like Java Messaging service (JMS), Enterprise Java Beans (EJB), WebServices (WS) and a few more. The author is clearly explaining how to use those different technologies within an Enterprise Service Bus (ESB) and how to implement it using the Java Business Integration (JBI) specification. The aim is to make you understand of how you could use any technology to achieve the Service Oriented Architecture.
A good point is that the theory is accompanied with a lot of examples based on Service Mix, which is an Apache JBI implementation. Those samples are insisting on EJB and WS, I would qualify them as realistic or real world samples. My opinion is that it could help a lot of people and companies not to rewrite their existing code but to rather reuse the code they already have and to make it working within a JBI container. You could find some explanations on how to make a real enterprise application using Service Mix and a huge assortment of useful packages like XStream or Axis. Also, on how to expose your EJBs as WSDL, which I find interesting. The samples provided in the book are accompanied with a lot of code and the whole build process. Thus even if you are not familiar with all those technologies you will be able to test and see the samples running.
All that is strengthen by the link to the Java Connector Architecture and to the point on how to exchange the information between all those different/heterogeneous systems.
While the book is correctly explaining the point of JBI, I would really appreciate to hear some words about the Service Component Architecture (SCA) and to see something about REST, but not only about WS. There are also a couple of references to VoIP and probably that a parallel could be shown with the SLEE (or JAIN SLEE) specification.
I also think there should be less explanation about WebServices and especially about the WS versioning, but some more words about XA transactions and services orchestration.
Finally, I really do recommend the book to those who are not familiar with ESBs or SOA and that want to learn something without investigating a lot on the web alone. Also, as I already mentioned to those who want to use a JBI container but have a lot of EJB and WS implementations around.