Well, now let's imagine that you spent 50 years developing a rich and complex library of code, say, in C++, and you make your living after all your hard work by licensing people to use your binaries, and in a gesture of goodwill you release the source to those binaries to allow people to see how it all works and some smartass just goes "yoink" and copies all 208 header files and starts redistributing them without so much as a by-your-leave and then goes on to make billions of dollars from it. Would you be happy about that?
It's not that simple though.
A lot of people seem to think that Android "stole" some open-source Java code. But that's not what the debate is.
The debate is whether or not an API
(in other words, the JavaDoc) can be copyrighted.
Android took the Java API
(the list of its classes and methods, which any developer can access) and reimplemented
those classes and methods in "Android Java".
Oracle claims that the API itself is copyrighted. They aren't claiming that Android developers stole Java's implementation
of those APIs- in other words, nobody is claiming that Android stole code
. They're claiming that coming up with your own implementation of an API is copyright infringement.
If Oracle wins this, that means that Joe Programmer can no longer implement a class called ArrayList that uses the same method names as the existing ArrayList class, without infringing on Oracle's copyright. Whether or not Oracle will enforce this is debatable, but larger-scale open-source projects that reimplement part of the API might be pretty worried about this. And that's the part that trickles down to us measly programmers.