Question - Code Loading with RMI + Ignore Prev. Posting

[Varun Rupela]

Hi:
I am trying to do Dynamic Code Loading with RMI and am encountering the following problem:
- I am not sure if it is a problem with the SecurityManager but following is the exception that I get:

Security is null java.rmi.UnmarshalException: error unmarshalling return; 
nested exception is: 
        java.lang.ClassNotFoundException: impldb_pkg.impldb_Stub 
java.lang.ClassNotFoundException: impldb_pkg.impldb_Stub 
        at java.net.URLClassLoader$1.run(URLClassLoader.java:200) 
        at java.security.AccessController.doPrivileged(Native Method) 
        at java.net.URLClassLoader.findClass(URLClassLoader.java:188) 
        at java.lang.ClassLoader.loadClass(ClassLoader.java:297) 
        at java.lang.ClassLoader.loadClass(ClassLoader.java:253) 
        at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:313) 
        at java.lang.Class.forName0(Native Method) 
        at java.lang.Class.forName(Class.java:195) 
        at sun.rmi.server.LoaderHandler.loadClass(LoaderHandler.java:354) 
        at sun.rmi.server.LoaderHandler.loadClass(LoaderHandler.java:132) 
        at sun.rmi.server.MarshalInputStream.resolveClass(MarshalInputStream.java:143) 
        at java.io.ObjectInputStream.inputClassDescriptor(ObjectInputStream.java:918) 
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:366) 
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:236) 
        at java.io.ObjectInputStream.inputObject(ObjectInputStream.java:1186) 
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:386) 
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:236) 
        at sun.rmi.registry.RegistryImpl_Stub.lookup(Unknown Source) 
        at java.rmi.Naming.lookup(Naming.java:84) 
        at clientdb_pkg.clientdb.main(clientdb.java:19) 

- I am using JDK 2.2, Standard Edition, v 1.3.0.
- In my application the stub is not available to the client locally and so the client must dynamically load the stub.
- As per Sun's RMI Tutorial - http://java.sun.com/docs/books/tutorial/rmi/running.html, I have used the following Security policy file to set up the Security Manager:
File Name: - "java.policy"

grant {
    permission java.net.SocketPermission "*:1024-65535",
        "connect,accept";
    permission java.net.SocketPermission "*:80", "connect";
};

- The client code begins with the following lines:

if (System.getSecurityManager() == null) 
{
System.out.println("Security Policy Not Set");
System.setSecurityManager(new RMISecurityManager());
}
else
{
System.out.println("Security Policy is Set");
}

- I run the client with the following command
java -Djava.rmi.server.codebase=http://localhost/~username/dist_obj_client/ -Djava.security.policy=java.policy clientdb_pkg.clientdb URL_remotehost
- If I use the above command to run the client program, I get the following output before the exception occurs:
"Security Policy Not Set".
Q1 - Is that expected? Shouldn't the SecurityManager be set to the java.policy file and not to a RMISecurityManager object?
Q2 - Does the exception mean that it might be a problem with the CLASSPATH of the shell in which RMI is started?
Thank you.