Java Remote Method Invocation (Java RMI)

Java RMI is a technological mechanism in which a server and client communicate and pass information while relying on the Java Remote Method Protocol (JRMP). Java relies heavily on Java object serialization, which allows the transmission of objects as a stream. RMI also allows a client and server to load new object types dynamically, as required.

RMI uses layered architecture:

• Application layer
• Stub and skeleton layer
• Remote reference layer
• Transport layer

Java RMI has numerous advantages, as follows:

• Portable to any JVM
• Part of Java’s write once run anywhere (WORA) approach
• Safe and secure: Uses built-in Java security mechanisms to facilitate system safety during user download implementations
• Easy to write/Easy to maintain: Facilitates write remote Java servers and Java clients that access those servers

Consider this scenario: User A creates a class, which has methods that provide a specific service. User B wants to user A's service. Through Java RMI, user B is able to invoke the object's method. User A places the service in the registry. User B is unaware of the service location, so it invokes the RMI registry. The registry then locates the service, which invokes the method.