Hi,
Ariba runs now on Android, see
http://ariba-underlay.org/wiki/Documentation/Android
for instructions. The runtime environment is not the managed Java
environment, but it runs directly on the device using the Android NDK.
To develop GUI-based apps you have to build a normal Java Android App
and use inter process communication, e.g. using JNI to communicate
with the Ariba-based application.
Best,
Chris