LipeRMI is a light-weight RMI implementation for Java. I decided to fork it from the original author as it has not been maintained for 3 years, and there were some changes I wanted to make.
The original project can be found here:
My interest in this project is as an RMI solution for Android. There is no java.rmi on Android, and porting it is cumbersome. LipeRMI has no dependencies outside of core Java (and all of them are satisfied under Dalvik) and is a very small code-base.
You can find JavaDoc here: http://jorgenpt.github.com/lipermi/