Java RMI (Remote Method Invocation, reference Chapter 5 of the textbook and Week-3 lecture) makes the local invocation and remote invocation use the same syntax to implement generic remote servers like the Compute Engine example in Week-3 lecture slides. However, Java RMI needs 2 HTTP servers to transfer Java classes between a RMI client and a RMI server at runtime. In addition, Java RMI applications need a RMI Registry for registering or looking up the remote objects.