>Fuchsia will be using Dart instead of Java

The current sysui is flutter/dart based, Flutter is google's newish mobile app sdk, the guys who started it have work on the chrome team, it's in alpha and has support android and ios.

https://github.com/fuchsia-mirror/sysui "Armadillo is currently the default system UI for Fuchsia. Armadillo is written in Flutter"

Here is an example of a rust programme, Xi editor, using flutter for the ui. https://github.com/fuchsia-mirror/xi