RMI exception "error marshalling arguments"

Question

I'm working on a RMI project that has two separated projects for Client and Server. I used start rmiregistry. When I try to run my Server application, I get an exception.

public class Runner extends UnicastRemoteObject {

    public Runner() throws RemoteException {
        try {
            ServerOperations so = new ServerSide();
            Naming.rebind("rmi://localhost:2000/MiveCoffeeService", so);
            System.out.println("Server is online.");

        } catch (RemoteException | MalformedURLException | FileNotFoundException ex) {
            Logger.getLogger(Runner.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    public static void main(String[] args) throws RemoteException {
        new Runner();
    }

}

The exceptions are:

Sep 11, 2015 9:05:51 PM ir.nscogroup.coffeemive.Runner <init>
SEVERE: null
java.rmi.MarshalException: error marshalling arguments; nested exception is: 
    java.io.NotSerializableException: dataaccess.ServerSide
    at sun.rmi.registry.RegistryImpl_Stub.rebind(Unknown Source)
    at java.rmi.Naming.rebind(Naming.java:177)
    at ir.nscogroup.coffeemive.Runner.<init>(Runner.java:29)
    at ir.nscogroup.coffeemive.Runner.main(Runner.java:38)
Caused by: java.io.NotSerializableException: dataaccess.ServerSide
    at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1184)
    at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348)
    ... 4 more

What is wrong?

Ona

Answer 1

thank you guys. this sample solved my problem.

package com.javacodegeeks.core.rmi.rminterface;

public class Configuration {

    public static final int REMOTE_PORT = 8888;
    public static final String REMOTE_ID = "RMI_EXAMPLE";
    public static final String REMOTE_HOST = "localhost";

}


package com.javacodegeeks.core.rmi.remoteserver;

import java.rmi.AlreadyBoundException;
import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;

import com.javacodegeeks.core.rmi.rminterface.Configuration;

public class RemoteServer {

    public static void main(String[] args) throws RemoteException, AlreadyBoundException {

        RMIImplementation rmiImplementation = new RMIImplementation();
        Registry registry = LocateRegistry.createRegistry(Configuration.REMOTE_PORT);
        registry.bind(Configuration.REMOTE_ID, rmiImplementation);
    }
}

Ona

This sample doesn't have anything to do with your problem. It's not materially different what you had already posted. – Grind

Answer 2

The exception stacktrace is telling you exactly what is wrong:

java.io.NotSerializableException: dataaccess.ServerSide

You're trying to serialize a non-serializable class, dataaccess.ServerSide. Solution: make your class and all necessary constituent classes implement the Serializable interface.

Retread

It is also worth mentioning that if some instance variables of serializable object can not or should not be serialized they should be marked with transient keyword – Maugre

Answer 3

The problem here is that ServerSide is neither an exported remote object nor Serializable. Almost certainly you intended the former, so you must either:

• make it extend UnicastRemoteObject, or
• export it manually yourself before binding, via UnicastRemoteObject.exportObject().

NB not both.

Grind