java.rmi.UnmarshalException: unable to pull client classes by server
- by andrews
Hi,
I have an RMI client/server set-up on two machines that works fine in a simple situation when the server doesn't require a client-side defned class. However, when I need to use a class defined on the client side I am unable to have the server unmarshall those classes. I suspect this is an issue with my java.rmi.server.codebase property that I pass in as argument to the client app. I followed Sun's RMI Tutorial trail and I think I have followed the steps exactly except that I don't specify a classpath argument when executing client and server because they execute in the directory right above the root package directory (however I tried that too with no effect).
The exceptions I get when attempting to execute the different client-side combinations described in detail below are all the same:
RmiServer exception:
java.rmi.ServerException: RemoteException occurred in server thread; nested exception is:
java.rmi.UnmarshalException: error unmarshalling arguments; nested exception is:
java.lang.ClassNotFoundException: test.MyTask
at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:353)
at sun.rmi.transport.Transport$1.run(Transport.java:177)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Transport.java:173)
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:553)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:808)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:667)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:636)
at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(StreamRemoteCall.java:255)
at sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:233)
at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:142)
at java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(RemoteObjectInvocationHandler.java:178)
at java.rmi.server.RemoteObjectInvocationHandler.invoke(RemoteObjectInvocationHandler.java:132)
at $Proxy0.execute(Unknown Source)
at test.myClient.main(myClient.java:32)
The details are:
My client/server rmi is set up over a home network behind a router. The router is assigned to a static ip address I will call myhostname. Appropriate port-mapping is set-up in the router that points to the right machines.
role, machine, os, ip-address:
server, venice, linux ubuntu 9.10, 10.0.1.2
client, naples, mac os x leopard, 10.0.1.4
I startup the server side as follows inside /home/andrews/workspace/epsilon/bin:
1 starting registry on the default port 1099:
venice% rmiregistry &
2 starting web-server on port 2001 pointing to code base for common interfaces:
venice% java webserver/ClassFileServer 2001 /home/andrew/workspace/epsilon/bin
3 starting server app (main class in test/myServer) which registers the server object:
venice% java -Djava.rmi.server.codebase="http://myhostname:2001/" -Djava.security.policy=server.policy -Djava.rmi.server.hostname=myhostname test/myServer &
Now the client side inside /Users/andrews/Development/Java/workspace/epsilon/bin:
1 start a local web server that can server client-side classes to the server (not sure if this is needed, but I added I tried it, and still no success; I have added port-mapping to the router for 2001 to venice, for 2002 to naples)
naples$ java webserver/ClassFileServer 2002 /Users/andrews/Development/Java/workspace/epsilon/bin/
Trying to run the client (note: I don't specify the -cp argument because client executes right above the root package directory):
1 try #1 using an http hostname
naples$ java -Djava.rmi.server.codebase=http://10.0.1.4:2002/ -Djava.security.policy=client.policy test.myClient myhostname
Note 1: the myhostname argument at the end is passed-in to the client so that it resolves to server's rmi hostname.
Note 2: I tried using localhost:2002 instead of 10.0.1.4:2002 too.
Note 3: I tried using myhostname:2002 since myhostname is assigned to the router and I have proper port-mapping set-up, this address should resolve to naples and not venice
2 try #2:
naples$ java -Djava.rmi.server.codebase=file:/Users/andrews/Development/Java/workspace/epsilon/bin/ -Djava.security.policy=client.policy test.myClient myhostname
Note 1: the code base url format is correct, I created a small program to convert current file directory path into a url and used that. using file:///Users... has same effect.
Other notes:
1 my server and client policy files correctly specify the path, as I've tested this setup with good and bad paths, and getting a security exception for bad path
2 this setup works if I don't use client-side defined objects, the client connects correctly to the server and the server executes.
3 when I place the client-side class on the server in the server's classpath, all executes fine.
All help is appreciated.
