RMI codebase confusion

Question

You'll have to excuse me if I am asking stupid questions, but I can't find the information I want in the documentation. I am working on an RMI client-server project with 3 jars client.jar, common.jar, server.jar. The common jar contains a Remote interface which the client looks up, and the server implements. The stub class is contained in the server jar (obviously).
Currently our method of distribution is to distribute all 3 jars to the client machines - I want to avoid this as it is unnecessary. I would therefore like to set java.rmi.codebase property in the server so that clients can download the stub classes at run-time. OK.
Our RMI app is being distributed on an internal network - suppose on the server machine (call it "ourserver.london.uk.ourco.com", the relevant Jar file would be at /usr/bin/my_app/jars/server.jar (or wherever).
The clients lookup rmi://ourserver.london.uk.ourco.com:1099/MY_EXPORTED_REMOTE. Questions:
1. Is this RMI "system" dependent on the server having an Http server?
2. If it isn't, how do I define the codebase other than "http://..."?
3. If it is (and the machine certainly does have an http server on it), how do I specify the codebase URL for the clients, given that the server is not "under" the http server (IYSWIM)?
I'd be glad of answers to these (reasonably simple) questions.
Chris

Answer 1

First of all, I would arrange things a bit differently. In both of the cases below, we assume a http server, it's location is unimportent, but it has to be reachable from the the client. It could be the same host as the server, or a third machine.
Option #1:
client.jar -- All client class files, including all class files of remote interfaces called by the client.
server.jar -- All server class files, including all stubs, and remote interfaces implemented and their implementations.
server_dl.jar -- Just the stubs.
The client host would contain just client.jar in the classpath.
The server host would contain server.jar and server_dl.jar in its classpath
server_dl.jar would also be placed on the http server and it's url would be the server's codebase.
Option #2:
client.jar -- All client class files, but none of the remote interfaces.
server.jar -- All server class files, but none of the stubs and no remote interfaces.
interfaces.jar -- The remote interfaces shared by client and server.
server_dl.jar -- just the stubs.
The client host would need client.jar and interfaces.jar in its classpath.
The server host would need server.jar, interfaces.jar and server_dl.jar in its classpath.
server_dl.jar would also be placed on the http server and it's url would be the server's codebase.
Now to answer your questions.
1. Is this RMI "system" dependent on the server having an Http server?If you want to have the client download the server stubs, then they have to be on an http server (I think a ftp url for the codebase may also work, but I have not tried it).
2. If it isn't, how do I define the codebase other than "http://..."?
You may be able to use a ftp url in which case the url would be "ftp://....."
3. If it is (and the machine certainly does have an http server on it), how do I > specify the codebase URL for the clients, given that the server is not "under"
the http server (IYSWIM)?The downloaded class files do not have to be on a http server that is on the same host as the RMI server. The RMI server's codebase can be any valid url (reachable from the clients) The only requirement is that the class files be reachable via the codebase. You do have to configure the client's network security so that it has permission to open connections to the codebase server.