RMI library is not included in Android API. That's really bad. I did a project where I need to use this feature, but couldn't do it. Unfortunately, if you google for this answer, some people tried to wrap RMI into self-defined library, but that does not work for everyone.
You are using RMI, I assume you will need access some database using RMI. Here is my solution:
I built a simple java server to as a connection.
I pull data from the source into the java server, use simple TCP connection to transmit data into my Android.
Also, Android transmit data into my sever, and my server forward data into the source server using RMI.
Not a direct way, but it's quite easy to do so. If you want to read more, I'd include my report on how I construct this intermedia Java server. http://www.shawnfandev.com/wordpress/2014/06/07/ibm-cognos-admin-android/
Good luck!