Fungal-android is a project mainly written in Java, it's free.
Fungal/Android kernel
This is the home of the Fungal kernel project which implements a Plain Old Java Object (POJO) kernel environment for Android.
http://jesperpedersen.github.com/fungal-android
http://jesperpedersen.github.com/fungal-android/maven2
http://github.com/jesperpedersen/fungal-android