US Supreme Court decides Google v. Oracle for Google
In short: using compatible APIs is fair use in the non-overlapping magisteria of common sense and US legal doctrine.
Copyright is a subject with vast scope and consequence. Oracle's tradition has always been using aggressive lawyers as their primary source of innovation. (Java was more innovative than anything Oracle's ever done; all Oracle did was to purchase it, which is not nothing, but does not morally justify treating events before their ownership as a personal affront.) Their angle has been the Lion King angle: everything the light touches is our kingdom, indivisible and equally covered by copyright. The majority opinion as well as Justice Thomas' dissent attaches to this train of thought by treating the entire code base as a pile of lines of fungible value.
Consider a copyright case of an affluent painter v. another, with the argument that the wood grain in the frame looks suspiciously familiar, never mind whether that's where the threshold of originality is met. Or one author v. another, about whether a point-by-point debunking of a crackpot theory should be seen as an unlawful derivative because of a similar looking table of contents, never mind whether it is a pedagogical arrangement for the reader.
Software platforms, programming languages, APIs, SDKs, modules and more all have many aspects to their construction and to their use, angles from which the entire thing is considered. As do most creative works, but here made even more complicated not only because of the distinction between library use or library production, but because of the entirely separate class of consumer in the executing computer, which by nature requires similarity to achieve compatibility.
Going back to those books, would simply having the same outward dimensions, typeface and paper stock be enough to call one of them infringing on the other? Or if we're satisfying humans by convention instead of computers by requirement, could a restaurant chain bring another restaurant chain to court over similar room layout and serving flow?
The ruling managed to find its way to a reasonable outcome, but if these are the tools used to chisel fundamental conditions for developers, companies and people the world over, we are all in bad shape for the future.