What is the RMI architecture?

Remote Method Invocation RMI consists of four layers and each layer performs specific functions:
1. Application Layer : contains the actual object definition
2. Proxy layer : consists of stub and skeleton
3.Remote Reference Layer : gets the stream of bytes from the transperent layer and sends it to the proxy layer.
4. Transportation layer : Responsible for handling the actual machine-to-machine communication.
http://wiki.answers.com/Q/What_is_RMI_Architecture

The server creates remotes objects and makes references to those objects accessible. Then it waits for clients to invoke methods on the objects. The client gets remote references to remote objects in the server and invokes methods on those remote objects. Java RMI is a mechanism that allows one to invoke a method on an object that exists in another address space. The other address space could be on the same machine or a different one. Java Remote Method Invocation (Java RMI) enables the programmer to create distributed Java technology-based to Java technology-based applications in which the methods of remote Java objects can be invoked from other Java virtual machines possibly on different hosts

I think your query has been answered already. So not adding anything here.