I used the book “OCA: Oracle Certified Associate Java SE 8 Programmer I Study Guide: Exam 1Z0-808” by Jeanne Boyarsky&Scott Selikoff. My english was not good enough therefore the first important thing for me was the writting style of book. Before buying the book I read some parts of it from “Look inside” in Amazon. I found its writing style simple and straighforward, so decided to buy it. In a short time I got used to the book. The book is very compact, and the reader is not overwhelmed by additional information. Everything is explained in a short and clear way. The book informs you about the topics that are out of scope for the OCA exam, so that you don’t need to read them. In this way you can save your time. The best thing about the book was that its predictions about out of scope questions for the exam were true. Indeed, I didn’t come across with those questions in actual exam.
The most confusing topic of the book for me was the Garbage Collection. At first it was hard to answer such questions. I encountered some tough questions regarding GC in coderanch and I couldn’t answer them. Therefore I needed to read extra information about GC from other sources. Then I learned the easy way to find right answers to such questions: using pen and paper. But there was only one question regarding GC in actual exam and it was absolutely enough to read only SYBEX.
The book covers 100% of exam objectives. I encountered only one thing (append() method with three parameters) in actual exam which doesn’t exist in the book.
If you look at Errata page you can see my name as the most reported person. But despite this, my opinions are very positive about this book. Most of these typos are minor and will not cause you problems in answering questions correctly in actual exam. I remember only two important errors that I encountered in Practise Exams and fortunately, they can be fixed (if they are fixed the next readers will not encounter these problems). But it is pity that these errors are still exist and haven’t been fixed yet, although they were reported several months ago. But in general this book is very good and I loved it very much 
I was able to answer only 3-4 questions in Assessment Test before reading this book, but after reading the book I increased my knowledge a lot. If online material quality is improved a bit (it is impossible to return previous questions in Practise Exam, it is impossible to look at your result after next login, there is no time limit information etc.) this study guide would become much better learning tool for future exam takers.
Thanks a lot to Jeanne and Scott for this valuable book 
