Ralph Goers wrote:
I think you are splitting hairs. "the implementation can be replaced" amounts to pretty much the same thing as the dependency can't be used. In fact, the way I read the original question it sounds like IBM is providing the API interface (not just the implementation) under an unacceptable license. I'm not sure how you get around that.
Now I'm confused. So perhaps it is time for me to add to the confusion.
An application programming interface (API) is a set of functions, procedures, methods, classes or protocols that an operating system, library or service provides to support requests made by computer programs.
Under US copyright law, such things are not subject to copyright:
In no case does copyright protection for an original work of authorship extend to any idea, procedure, process, system, method of operation, concept, principle, or discovery, regardless of the form in which it is described, explained, illustrated, or embodied in such work.
[17 USC 102(b)]
What then is IBM claiming?
It is always important to keep our contributors' potential copyright claims separate from their patent claims and to classify them properly. Otherwise, we'll be asking for licenses we don't actually need. That isn't what "software freedom" is supposed to be about.
To misquote the old Santa Claus line, "Yes, Virginia, there is a public domain of ideas and APIs, and Apache ought to feel free to implement them without asking for permission."
But maybe I'm misunderstanding your questions about this....