In theory, the market will adapt to track this layer of copyright, but the short-term shock effect is large. Since nobody's assumed APIs are copyrightable 'til

In theory, the market will adapt to track this layer of copyright, but the short-term shock effect is large. Since nobody's assumed APIs are copyrightable 'til now, nobody's been keeping track. So every API currently in use is under threat (especially since in the US, you don't have to file a copyright claim to have copyright; if you can just prove your API came first and there's reason to believe the younger API was familiar with your own, you can claim statutory damages, IIUC). It'll be exciting to see how many of Oracle's APIs are 100% derivative of some software released under Copyleft licenses... ;)