Adding new Attribute Interfaces to java-api.

[Tom Zeller]

>>Interfaces for those objects were explicitly removed in v3, reversing
>>warrants a review of that fundamental design choice. So, no, I am not
>>in favor at the moment because the original author specifically did
>>not do so.
>
> I don't like locking people into specific classes in Java as an API for
> components like this because it limits implementation flexibility. I do
> see that it was changed, but I really have no understanding of why, or why
> it would be a good thing. I see it as a pretty universal bad.

I remember talking with Chad about the removal of interfaces, and I
think his line of reasoning was that what we lose in flexibility we
gain in simplicity, and the flexibility gained was 'never' used anyway
(my quotes).

If we are serious about re-working our API then someone should
probably ping Chad for more background, I believe it was a thoughtful
decision.