Codebase run RMI server .NoClassDefFoundError:

Question

If I run the folllowing from the solaris command line
java -cp /junk/jdev+/jdev/src -Djava.rmi.server.logCalls=true -Djava.rmi.server.codebase=file:////junk/jdev+/jdev/src/ -Djava.security.policy=/junk/jdev+/jdev/src/jdev/server/policy jdev.server.RMIServerDBAdapter
my RMIServerDBAdapter binds regardless of my current working directory. In other words the RMI server
runs and binds as expected.
If I remove the classpath clause of the java command (-cp /junk/jdev+/jdev/src) then the RMI server
will only run and bind if my current working directory is the "root" of the package.
In this case if my current working directory is /junk/jdev+/jdev/src the RMI server will run and bind as
it should. If my current working directory is at the root of the solaris file system ( / ) I get the following error
Exception in thread "main" java.lang.NoClassDefFoundError: jdev/server/RMIServerDBAdapter
My question is why doesn't the code base clause of the java command point to the root
directory of the package /junk/jdev+/jdev/src. It seems to me that the codebase clause
would point to the root directory of the package allowing the RMI server to run and bind as expected
regardless of the current working directory.
I cannot get this to work. I have tried 0-4 slashes (file:/, - file:////) that did not seem to help.
The package statement in the java source files is
package jdev.server
Thank you in advance for your help.
Michael
[email protected]

Answer 1

Hi Ciaccio,
Your question is doesn't clear enogh to me to answer it straight... But I'll try... :)
First you must not mix the reason and usage of the codebase and classpath. Classpath is locally parsed and used, codebase is remotely parsed and used (at the registry and at the client side).
Your server program cannot start if you don't tell to the system where to find the needed classes. That's why you have to specify the root path of the jdev.server.RMIServerDBAdapter in the CLASSPATH (from that point will search the java system the jdev dir, the server dir and the RMIServerDBAdapter object) .
If the Java system is unable to locate any of a needed class it throws a nice exception during the startup of the server program.
The codebase property is used by the client and the registry to locate the stub objects (and return types and parameter types) if those cannot be found on their local classpath. This path (or it would be more accurate to call what it is: URL) must be an absolute address (path, URI, etc), because the clients and the registry can be started anywhere. This way you also have to set RMISecurityManager and polici files also to your client because of dynamic class downloading...
Last thing:
Note the line above: ...if those cannot be found on their local classpath... If the stubs and the param/return types are present in the registry's and the clients local classpath then you don't have to specify codebase property at the server side because it is not parsed at all.
I hope I could help,
Sanyi