Can't start RMI server using JAR file

Question

I found it interesting that if I start my RMI server from
a plain directory, everything goes fine.
But if I jar all these necessary files into a jar file,
and start my RMI server with command below
java -jar server.jar
UnmarshalException and ClassNotFoundException are
thrown to indecate that my stub class can't be found
(which I'm sure my stub class is in jar file)
Why is jar file so special that it can't act like
what it originally does when it hasn't been jared?
or I really should take care of some configuration
before I really can run a jar file?
thanks

Answer 1

To clarify few things...
What I don't understand is that when I convert all my
directories and class files properly into the jar file, they
just can't work properly.
I don't know if it's a problem of JAR file,
or it's RMI that make this JAR file special?
I'll simulate my JAR file structure that listed below,
these structure works fine when they have'nt been
converted into JAR file.
META-INF/
META-INF/MANIFEST.MF
a/b/x1.class
a/b/x2.class
a/b/c/Y.class
a/b/c/Y_Skel.class
a/b/c/Y_Stub.class
And when I use command "java -jar server.jar"
to run my application, ClassNotFound exception
is thrown to indecate my stub class is not found.
Is there anything I can do to correct this?
thanks