http://arstechnica.com/apple/2015/02/silver-brings-apples-swift-language-to-the-net-and-java-worlds/
“Silver” brings Apple’s Swift language to the .NET and Java worlds

http://elementscompiler.com/elements/silver/

Silver is a free implementation of Apple's Swift programming language.

With Silver, you can use Swift to write code directly against the .NET, Java, Android and Cocoa APIs. And you can also share a lot of non-UI code between platforms.