I've been half expecting that Google would announce something like this at IO as a counter to Swift. But this makes it look like an unofficial side project.
It is an unofficial side project. Same as what the go team is doing with their language.
I don't expect the Android team to switch language soon. In their own words, the engineering cost to rewrite the whole stack in another language is just too big, especially since they are not convinced that it is an obvious way to improve the platform.
In the near future, I would be less surprised to see them adopt Kotlin : it fixes many of java weaknesses, accepts java classes and produces compatible bytecode.
I think its pretty exciting that Google is attacking the cross-platform development problem from many angles.
They are building Java apps like Inbox that work on many platforms, using tools like Google web toolkit and J2ObjC.
Plus there is the App Runtime for Chrome, which basically allows Android apps to run in Chrome on any desktop OS.
And now there is this Dart approach. Hopefully these different teams are collaborating and will eventually converge when one of these tools eventually takes off.
It was announced/demoed at the Dart Dev Summit earlier this week (see talk: https://www.youtube.com/watch?v=PnIWl33YMwA) which imho is fitting. It is still a bit early but you can already follow the related GitHub projects:
Imho it makes sense for both Google on Android (Java) and Apple on iOS (Objective-C) to provide more (and more) modern alternatives to develop applications for their platforms.
There certainly are people who are happy with Java and Objective-C but there are many who'd like to use different languages/runtimes/ecosystems.
The popularity of projects like Cordova and CrossWalk show how much demand there is to build applications using web technology even if you have to pay for it in performance.
Sky is a way to use Dart without having to compromise on application performance nor on development feedback speed and debugging tools.
Also think of the people (whether large or small companies) who have to support multiple platforms (Web, Android, iOS, Server, …) simultaneously and right now are forced to use multiple languages and tools for building/debugging. This is incredibly costly, especially if you want to deliver high quality products.
