I'd like to know if someone who's a beginner about Web development in Java can read this book without too many problems.
According to Pactpub website, this book is intended for Java developers who want to develop web frontends for their enterprise applications using Apache MyFaces as JSF implementation. Some basic knowledge of JSF is expected.
As Anil says, some basic JSF knowledge is expected for the book. However, I recently saw a JSF beginner being pretty successful after reading the book. The book uses an example case, so if you follow the book from cover to cover, you will be building a fully functional web application from scratch. I think that approach will work pretty good, even if you don't have JSF experience.