Clarification in page 340,341 of the OCP Java SE 8 Programmer II Study Guide (Sybex)

[Ramya R Subramanian]

I saw in Javadocs that Future is a interface

But in the Sybex guide Page 340 3rd para last line, it says "when discussing the Future class", ...then class must be interface

I saw this again in Page 340 under Waiting for Results , in the para line it says "Future class includes methods".

and similarly in page 341 in the second paragraph after the code it says "As Future<V> is a generic class".

[Scott Selikoff]

I'll admit it, that ones mine! Since you never have to work with the specific implementation class of Future when studying concurrency for the OCP 8 exam, I got used to thinking of it as a class.

I love the factory pattern (where the specific return class type is "hidden" in favor of coding to an interface) but it has the side effect of you tend to think of an instances of an interface as belonging to a class with the same name.

Same thing happens when working with NIO.2, Path is an interface but it often is used like a class, since you are unlikely to ever work with the file system dependant class type. We did fix similar errors for Path, must have missed some for Future in Chapter 7!

If you call get() on a Future instance of our book, it shall be fixed

[Ramya R Subramanian]

Scott Selikoff wrote:If you call get() on a Future instance of our book, it shall be fixed

Sure. No problem

[Jeanne Boyarsky]

Noted in the errata. Thanks.