RMI tutorial errors with ComputeEngine

Question

So I've spent quite awhile trying to find an answer from other people having trouble with the RMI tutorial, but I'm completely stumped on this. I'm doing this tutorial through eclipse.

My ComputeEngine Class. This is just copied from the tutorial, so I don't think there's anything wrong with it.

import java.rmi.RMISecurityManager;
import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
import java.rmi.server.UnicastRemoteObject;
import compute.Compute;
import compute.Task;

public class ComputeEngine implements Compute {

    public ComputeEngine() {
        super();
    }

    public <T> T executeTask(Task<T> t) {
        return t.execute();
    }

    public static void main(String[] args) {
        if (System.getSecurityManager() == null) {
            System.setSecurityManager(new RMISecurityManager());
        }
        try {
            String name = "Compute";
            Compute engine = new ComputeEngine();
            Compute stub = (Compute) UnicastRemoteObject.exportObject(engine, 0);
            Registry registry = LocateRegistry.getRegistry();
            registry.rebind(name, stub);
            System.out.println("ComputeEngine bound");
        } catch (Exception e) {
            System.err.println("ComputeEngine exception:");
            e.printStackTrace();
        }
    }
}

I start the rmiregistry in the command line with

set classpath=
start rmiregistry

My VM arguments in eclipse are:

-Djava.rmi.server.codebase=file:/C:/Users/Kevin/workspace/RMI/bin/
-Djava.rmi.server.hostname=Compute
-Djava.security.policy=server.policy

I have the compute.jar file and the the server.policy files in the bin folder. I granted all permissions for the policy file.

grant{
    permission java.security.AllPermission;
};

After all that, I run ComputeEngine and get the following errors:

ComputeEngine exception:
java.security.AccessControlException: access denied (java.net.SocketPermission          127.0.0.1:1099 connect,resolve)
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkConnect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(Unknown Source)
at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(Unknown Source)
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(Unknown Source)
at sun.rmi.transport.tcp.TCPChannel.createConnection(Unknown Source)
at sun.rmi.transport.tcp.TCPChannel.newConnection(Unknown Source)
at sun.rmi.server.UnicastRef.newCall(Unknown Source)
at sun.rmi.registry.RegistryImpl_Stub.rebind(Unknown Source)
at engine.ComputeEngine.main(ComputeEngine.java:31)

It seems like it has some kind of problem with rebind, but I don't understand what. I also don't understand the AccessControlException, when I have the policy file. I've checked to make sure the rmiregistry is still running, and I don't close the empty window that comes up after starting it.

So yeah, I'm lost.

Answer 1

Clearly your security policy file isn't being found. It would need to be in the current working directory when you execute the program. Run your program with -Djava.security.debug=access,failure to see exactly what's going on.