I have just passed the exam 1Z0-808 OCAJP SE 8 with score 87% today(07/16).
I studied OCA: Oracle Certified Associate Java SE 8 Programmer I Study Guide by Jeanne Boyarsky and Scott Selikoff. Very good book with many examples, review questions and a lot of code.
I have also used Enthware mock exams and OCA book mock exams, to test my knowledge before the real exam.
In my company, I am the first certified in Java 8.
Very Happy now, but this is only the beginning.