Java remote method invocation

A typical implementation model of Java-RMI using stub and skeleton objects. Java 2 SDK, Standard Edition, v1.2 removed the need for a skeleton.

The Java Remote Method Invocation API, or Java RMI, is a Java application programming interface that performs the object-oriented equivalent of remote procedure calls (RPC).

1. 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).
2. 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 programmers of the original RMI API generalized the code somewhat to support different implementations, such as an HTTP transport. Additionally, the ability to pass arguments "by value" was added to CORBA in order to support the RMI interface. Still, the RMI-IIOP and JRMP implementations do not have fully identical interfaces.

RMI functionality comes in the package java.rmi, while most of Sun's implementation is located in the sun.rmi package. Note that with Java versions before Java 5.0 developers had to compile RMI stubs in a separate compilation step using rmic. Version 5.0 of Java and beyond no longer require this step.

Jini offers a more advanced version of RMI in Java. It functions similarly but provides more advanced searching capabilities and mechanisms for distributed object applications.^[1]

See also

• Cajo
• Serialization
• Jini

References

External links

• The Java RMI tutorial - a good starting point to learn RMI. Also check the Hello World in RMI
• The RMI page in the JDK docs
• java.rmi (Sun's Java API Reference for the RMI package)
• The RMI forum on java.sun.com
• Wollrath, Ann; Riggs, Roger; Waldo, Jim (PDF). A Distributed Object Model for the Java System. http://pdos.csail.mit.edu/6.824/papers/waldo-rmi.pdf. Retrieved 2009-02-11.