RMI is an easy way to communicate between JVMs. It is particularly helpful for the encapsulation of e.g. legacy JNI code or any other unstable part of the system.
Java EE 7 Workshops: Bootstrap, Effective, Architectures, June, 13th-15th, Munich's Airport
On demand workshops: Java EE 7 Bootstrap, Effective Java EE 7, Java EE 7 Testing and NEW: Java EE 7 Microservices are available for streaming