rmi

http://docs.oracle.com/javase/6/docs/platform/rmi/spec/rmi-arch3.html

 

a remote object is one whose methods can be invoked from another Java virtual machine

 

A method dispatched by the RMI runtime to a remote object implementation may or may not execute in a separate thread. The RMI runtime makes no guarantees with respect to mapping remote object invocations to threads. Since remote method invocation on the same remote object may execute concurrently, a remote object implementation needs to make sure its implementation is thread-safe.