MC78 Lab 4: The Return of NetFlip (Fall 1998)

Due: December 11, 1998

Goals of the lab

In this lab, you and your partner(s) will get some experience using RMI, the Java Remote Method Invocation facility, which is one example of a modern distributed object system. To do this, you will rewrite the NetFlip and FlipServer programs from lab 1 to use RMI instead of sending bytes over sockets.

If you would rather do some other simple client/server program using RMI, that is fine too. However, check with me on the suitability. One aspect I would like to see is that sometimes the server contacts the client, rather than always the client contacting the server.


You can use as starting points not only the code from lab 1, but also the RMI documentation, which is on the web at In particular, this includes the RMI Tutorial, the code from which I showed on the overhead in class. Your friendly neighborhood instructor is also a resource.


Remember that the client and the server are quite asymmetrical. The clients will need to find the server by name, but can then register with the server, so that the server knows the clients without doing a naming lookup. Similarly, when the client discovers that the server has failed, that is quite a different matter than when the server discovers that the client has failed.

You will be able to strip quite a bit of the existing code out of NetFlip and FlipServer. In particular, all the multi-threading stuff that gave you such grief in lab 1 can go. (You will still need synchronization, but you won't need to create any threads.)

You will almost certainly find it less hassle to leave NetFlip an application program rather than make it an applet.

Instructor: Max Hailperin