After doing the whole \"enterprise\" programming for a while, I\'m seriously disillusioned by the language itself and always feel quite hampered if I have to go back to it. The
You can build an android app with the knowledge of just Html/css/Js. So there is no need of Java to create an android applications. Visit here for some basic knowledge. [1]http://www.chromeearth.com/requirements-cordova-platform/
This link has some details on how to get scala apps working on android. I'm sure you can do something similar for clojure or other jvm languages.
Ruboto is aiming to bring JRuby in.
Have you looked at Mirah? It gives you a Ruby-like syntax and compiles to Java. It’s been labeled the CoffeeScript of Java.
Xamarin Studio let's you build in C#/Mono and build apps for both Android and iOS. Now the presentation layers have to be implemented differently on both platforms, but for the ability to use C#, it's a big Win.
DroidScript is probably one of the easiest of the above mentioned development tools to use for Android development. Like Cordova you use JavaScript, but unlike Cordova you have the choice of using native Android GUI's or HTML5 to build your App interfaces.
Also you still have access to all the devices sensors/hardware without needing to import loads of complicated plugins. Plus you get the bonus of being able to develop actually on your mobile device if you need to (you can even build APK's and publish them from your device).
I would say its very good for beginners or prototyping but perhaps not flexible enough for seasoned developers.
I have never used it, but Kotlin is a new language that runs on the JVM developed by JetBrains (the maker of Android Studio) that deserves a mention. The Kotlin website claims the language is 100% interoperable with Java and has a tutorial for Getting started with Android and Kotlin and Android Studio now actually comes with Kotlin support.