So...I guess this api signature for string concatenation is on the verge of being owned by oracle forever. Perhaps I can create a non-derived work by adding a few extra arguments.
I'd bet that isolated examples couldn't be copyrighted any more than a single sentence in a novel couldn't be copyrighted. Doesn't it have to do with the whole work?
The case is about APIs, not the whole work. By their very nature, all APIs are both:
1. Single sentence.
2. Usually obvious. In fact, just about every API definition in the above linked String method list is blatantly obvious, and many of the APIs look similar to ones in various other completely incompatible languages.
So even if you argue the copyrighted work is comprised of the whole set of APIs, it may be patent-able as an invention, but it does not seem reasonable to suggest it be protected by copyright.