The book is mostly about the use of the Java EE APIs. As such, it's not all that affected by the evolution of the core language from 6 to 7 to 8.

However, it probably will be affected by the evolution of the Java EE API. EE 6 was a huge, massively simplifying, change from EE 5, which is why it needed a book like this. EE 7 was a fairly incremental change from EE 6, and EE 8 is set to also be a modest step forward.

The biggest change in EE 8 - and i don't know whether to laugh or cry about this - is that Java will be getting a standard web MVC layer. Fifteen years after such things first appeared on the scene, and five years after they became passé. Maybe there'll be an API for controlling dialup modems or AIM clients next.