Google had previously won in court over its use of some Java APIs within Android. The judge had ruled that it was within fair use for Google to build on the Java API because it was offered free.
But today a federal court overturned that decision, opening the way for Oracle to demand money from Google for the time it was using the APIs without permission. Google had used Java's APIs because it wanted to make developing for Android as easy as possible. The move achieved this, and Android no doubt grew quickly as a result, and Oracle wanted money from the outset.
The original jury couldn't decide if the use was fair or not, but that didn't end up mattering because the judge tossed the case out anyway, claiming that it wasn't possible to copyright an API. Today's judgement suggests that the Federal Circuit Court of Appeals does not agree. The next step in the case will be for Oracle to take it to the Supreme court, which will probably take years.
This is something of a big deal in terms of precedent too, because APIs are widely used for one service to build on the core of another. APIs are crucial for helping with software development, and letting companies work with each other, without the need of complicated legal contracts to do so. And what's more, it will also cause problems for applications that leverage services without an API, but via clever engineering. That could affect any number of apps you currently use and mean that only "official" apps will work with a service.
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