[zmmmmm]

I don't think it's actually about that.

APIs are facts, and facts are not copyrightable. How is an API a fact? You have a system, in the real world. It is a "thing". There are facts about this thing: if you send it particular bytes, it does X, if you send other bytes, it does Y. The fact that it does this is empirically derived. There are not two or more options for it, it's like gravity or electromagnetism. APIs are facts about the systems they apply to, so while there is creativity in designing them, there is no creativity in building a system that interacts with them. There is exactly one way derived from the empirical fact of how it works.

Where the case IS weak is that there IS creativity in how you document and organise the API. And I'm pretty sure Google's re-implementation was very similarly organised to the real Java. That will be the crack Oracle will be trying to exploit here. But its not actually about the original work being "original" or even "creative".