Passed 1Z0-810 with 81%.
The following are my study materials.
What's New in JDK 8
Mikalai Zaikin's notes.
Mikalai's Quiz was a really helpful to pass the test.
I saw Lambda, nested inner class, merge, ZonedDateTime, functional interface, etc. Well, exam covers all topics in 81 questions. but i saw many merge questions.
Good Luck to everyone.