Sharing code across the client and server is also important. Not just code sharing amongst clients. The JVM is going to be the preferred server target at Googl

Sharing code across the client and server is also important. Not just code sharing amongst clients. The JVM is going to be the preferred server target at Google over C# and .NET by a wide wide margin. Which probably rules out Xamarin. Add to that the fact that native Android is already Java (source). And GWT is a mature technology that is Google maintained. Seems like the logical route to take.