IntensiBuild
Minimal build system with support for building Android, J2ME, J2SE desktop and J2SE Web-Start applications.
I created IntensiBuild a few years ago for one of my first commercial J2ME projects. Looking at J2ME Polish I decided I needed a smaller, more minimalistic build system. Ruby was chosen as the implementation language. A generic Ant build file implements the Java and J2ME build tasks.
This project is hosted at github. See the description there for more details.