There are two common implementations of the API. The original implementation depends on Java Virtual Machine (JVM) class representation mechanisms and it thus only supports making calls from one JVM to another. The protocol underlying this Java-only implementation is known as Java Remote Method Protocol (JRMP). In order to support code running in a non-JVM context, a CORBA version was later developed. Usage of the term RMI may denote solely the programming interface or may signify both the API and JRMP, whereas the term RMI-IIOP, read RMI over IIOP, denotes the RMI interface delegating most of the functionality to the supporting CORBA implementation.
The original RMI API was generalized somewhat to support different implementations, such as an HTTP transport. Additionally, work was done to CORBA, adding a pass by value capability, to support the RMI interface. Still, the RMI-IIOP and JRMP implementations are not fully identical in their interfaces.
The package name is while most of Sun's implementation is located in the
sun.rmi package. Note that with Java versions before Java 5.0 it was necessary to compile RMI stubs in a separate compilation step using
rmic. Version 5.0 of Java and beyond no longer require this step.
A more advanced version of RMI in Java is Jini - it is similar but provides more advanced searching capabilities and mechanisms for distributed object applications .