Modernized Java for Android Development (lambda expressions, etc.) It compiles to Java source, so seamlessly work on...

Modernized Java for Android Development (lambda expressions, etc.) It compiles to Java source, so seamlessly work on Android.   

http://www.eclipse.org/xtend/

https://github.com/tobykurien/Xtendroid - it is an Xtend based lib for easier development

http://www.infoq.com/articles/unusual-ways-to-create-a-mobile-app - a good article about cross-platform (iOS, Android) mobile development based on RoboVM and Xtend

And finally the G+ group of the Xtend language: 
Eclipse Xtend 
http://www.eclipse.org/xtend