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.
Although there is significant overlap with the JDK 1.4 exam I guess that there is at least 30% new material to learn. Some of the new topics are
regular expressions the Locale class the Text class serializing streams generic collections generic method parameters input/output classes for-each looping locales (dates and currencies) enums autoboxing OO concepts (coupling and cohesion) jar files sorting and searching collections covariant returns JavaBean naming varargs