It's more analogous to -- very analogous to -- the "clean room" BIOS clones that enabled the PC Clone industry to take off (and made IBM-compatible PCs actually affordable; before the clones took off, IBM's prices made Apple seem like a bargain).

Atari and Amiga prices were quite competitive, offering much more than those early expensive PCs.

Except Google did not do a clean room clone. They simply copied, thus violating the whole point of copyright. If they had developed their own API that simply used different names but was functionally identical, they would not have violated copyright. Copyright protects against copying. They didn't do that because they wanted to take advantage of the huge existing JAVA developer base who would easily be able to use the copied APIs to develop for Android. I.e., Google chose to copy and thus are liable for that choice.

AS has been covered elsewhere, an API is a functional description and not copyrightable, irrespective of what a specific court says. This specific court has had its rulings slapped about so much by the next higher court, it is a wonder that they haven't just packed up and gone home.

That is why telephone books and others things are not copyrightable. They are lists of facts. API's are lists of facts, a functional specification for use.

There are consequences if this stands and it will not be to our benefit as programmers, developers, designers, etc. Nor will it be to the benefit of society as a whole.

Telephone books are copyrightable. This is black letter law. As said by the Supreme Court in Feist, "Notwithstanding a valid copyright, a subsequent compiler remains free to use the facts contained in another's publication to aid in preparing a competing work, so long as the competing work does not feature the same selection and arrangement,"

In other words, if it does feature the same selection and arrangement, it is a violation of copyright.

Your statement that APIs are not copyrightable is not true as well.

Where can I go copyright my phone number? I want to make those marketers pay a royalty for even storing my number.

An api with different names isn’t functionally identical, at least not without some sort of very weird indirection.

It depends on your meaning of functionally identical. In the hypothetical non-copied Android ecosystem, it could be functionally identical. In terms of interoperating with Java, no. But I fail to see the relevance of the latter point with respect to copyright. Copyright says: don't copy. If that unfortunately makes it difficult to leverage the existing Java developer base for your multi-corps next megaproject, too bad. Develop your own ecosystem.

The Java API is hundreds of classes and thousands of methods. It is far beyond something as simple as the height of a door.

I don't see how the size of the spec has anything to do with it. It could be the standard height of doors or the standard interface/protocol between every sensor and smart component in a smart home.

What if I create my own smart home server that can be a drop in replacement for some commercial product using just what I've gather from their public API? Is that infringement, when the underlying implementation is entirely my own?

You can't copyright trivial work so the size of the spec matters.

It depends on how you create your server. If you go to their website, look at their API, and start typing identical code then that's not ok. It's pretty clearly copying. If you do black box testing and then write your own API that's fine. It's clearly not copying but a new original work.

And what criteria should be used to tell when an API is complex enough to be copyright-able?

Generally, anything can be copyrighted as long as it's sufficiently original. The phrase “I have abandoned my search for truth and am now looking for a good fantasy”, for example, is under copyright by Ashleigh Brilliant, who own a case against a t-shirt manufacturer using it.