"OCA Java SE 7 Programmer I Certification Guide" is Manning's book for developers looking to get the new entry level Java certification.
I wouldn't use this book to learn Java; I'd use it as a second Java book to get ready for this exam. (Nothing wrong with this - the book doesn't claim to teach you Java. I only mention this so you have proper expectations. I actually like when a book separates objectives between teaching from scratch or exam prep.)
The book comes with mock questions after each chapter and one full mock exam. There are also "twist in the tale" exercises sprinkled throughout the book which get you to realize how small changes to the code can change the behavior of the code.
The explanations are clear. Analogies prevent you from getting bored. There are great diagrams throughout the book.
Overall, I think the best test of a cert book is whether it prepares you for the test - this book does.
Disclosure: I will be receiving a copy of this book from the publisher in exchange for being the technical proofreader for the book.