An article at Dr. Dobb's looks into the consequences of a dangerous idea from Oracle during their legal battle with Google: 'that Google had violated Oracle's Java copyrights by reimplementing Java APIs in Android
The issue is very much unsettled in the courts, but the judge in this case instructed the jury to assume the APIs were copyrightable. 'In a nutshell, if the jury sides with Oracle that the copyrights in the headers of every file of the Java source base apply specifically to the syntax of the APIs, then Oracle can extract payment and penalties from Google for having implemented those APIs without Oracle's blessing (or, in more specific terms, without a license).
Should this come to pass, numerous products will suddenly find themselves on an uncertain legal standing in which the previously benign but now newly empowered copyright holders might assert punitive copyright claims. Chief among these would be any re-implementation of an existing language.
So, Jython, IronPython, and PyPy for Python; JRuby, IronRuby, and Rubinius for Ruby; Mono for C# and VB; possibly C++ for C, GCC for C and C++ and Objective-C; and so forth. And of course, all the various browsers that use java-script might owe royalties to the acquirers of Netscape's intellectual property.