I have a few questions:
For whom is Java 8 New Features intended?
What are the significant differences (content) between Java 7 New Features Cookbook and Java 8 New Features?
What is one of the biggest additions in Java 8?
Why did you choose an avocado as your cover?
Java8 is of course for everybody who wants to use it.
A really big feature is lazy execution; you can select things from a stream and the code executes lazily so there is no excess work done behind the scenes.
Java 8 New Features is aimed more at experienced programmers as opposed to someone new to the language. It is intended to help Java programmers come up to speed on new Java 8 features. With regards to the differences between Java 7 and Java 8, there have been more basic language enhancements in Java 8 as opposed to Java 7. The changes to the language in Java 7 were limited whereas we have seen the introduction of default methods, lambda expressions, and streams to Java 8.
There is nothing significant about the avocado on the cover, other than the fact I like avocados. However, I am working on a jMonkeyEngine book where we will use bananas.