This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
The concurrency update for 5.0 is relatively huge. This was one of the reasons why our book was practically a total rewrite. Some stuff, like the atomic libraries, required new techniques -- in this case, understanding optimistic locking.