Name: krT82822 Date: 06/29/99


Ok, here's an odd one for you. I had a situation in which I
have one RMI server and two clients. For each of the three
separate executables, I create a separate jar file, containing
only those files required by the server or client in question.

In my server, I have an RMI-exported class called GanymedeServer.
Each of my two clients (primary client and admin console) include
GanymedeServer_Stub.class in their jar files.

When I went to run my admin console applet out of its ganymedeAdmin.jar
file on Win32 with Plug-in 1.2.2, however, the applet failed
on initialization, complaining that it could not find
arlut/csd/ganymede/GanymedeServer_Stub.class, despite the fact
that it was clearly in the jar file.

What turned out to be the real problem is that one of the remotely-callable
methods defined in GanymedeServer_Stub.class (login())used an RMI remote
interface type (Client) as a parameter. The login() method is never
called by the admin console, which uses a different method (adminLogin())
for establishing its connection to the server. So, no need for
the Client.class remote interface class in the admin
console's jar file, right?

Nope. The RMI classloader gets confused by the inability to
find the RMI interface referenced in one of GanymedeServer_Stub's
remote method signatures, and throws up its hands in protest,
without explaining clearly what the real problem is, as follows..

Opening http://csdsun9.arlut.utexas.edu/ganymede/ganymedeAdmin.jar no proxy

CacheHandler file name: C:\Program Files\Netscape\Users\jonabbey\cache\M1N3T2DM.JAR

Opening http://csdsun9.arlut.utexas.edu/ganymede/arlut/csd/ganymede/Client.class no proxy

CacheHandler file name: null

java.rmi.UnmarshalException: error unmarshalling return; nested exception is:
java.lang.ClassNotFoundException: arlut.csd.ganymede.GanymedeServer_Stub

java.lang.ClassNotFoundException: arlut.csd.ganymede.GanymedeServer_Stub

at java.io.ObjectInputStream.inputObject(Unknown Source)

at java.io.ObjectInputStream.readObject(Unknown Source)

at java.io.ObjectInputStream.readObject(Unknown Source)

at sun.rmi.registry.RegistryImpl_Stub.lookup(Unknown Source)

at java.rmi.Naming.lookup(Unknown Source)

at arlut.csd.ganymede.GASHAdmin.run(GASHAdmin.java, Compiled Code)

at java.lang.Thread.run(Unknown Source)

RMI: RemoteException during lookup.

My request is either that the missing RMI interface definition
not be complained about until the RMI method that includes
that interface in its signature is called, or that at a minimum
the returned exception accurately describes which file could
not be loaded.

Adding the Client.class file to my admin console's jar file
corrected this problem, but this was extremely confusing and
caused a number of users some heartache.
(Review ID: 84556)
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