Android Ported to C# – Xamarin

Code different; also see Xamarin XobotOS ports Android to C# and .NET framework (Slashgear); in another weird platform/tool permutation, see Skype replaces P2P supernodes with Linux boxes hosted by Microsoft (updated) (Ars Technica)

“Oracle and Google are currently in a $1 billion wrestling match over Google’s use of Java in Android.
But Java is not the only way to build native apps on Android. In fact, it’s not even the best way: we have been offering C# to Android developers as a high-performance, low-battery consuming alternative to Java. Our platform, Mono, is an open source implementation of the .NET framework that allows developers to write their code using C# while running on top of the Java-powered operating system, and then share that same code with iOS and Windows Phone.”

Android Ported to C# – Xamarin