RMI Method not supported by remote object: java.rmi.UnmarshalException: unrecognized method hash

Question

I'm having a weird problem in my Bank - Client (server client via RMI) application.

I have Bank class that implements IBank extends Remote. This Bank Class has several methods, checkClient, getBankAccount etc.

The problem is, I can call the method checkClient (boolean) just fine from the clientside, all other methods give the UnmarshalException

Bank class on serverside:

public class Bank extends UnicastRemoteObject implements IBank { 

    private BankName bankName;

    private String URL;

    @Override
    public boolean checkClient(String username, String password) {
        Client client = db.getClient(username, password);

        if(client.getUsername() == null && client.getPassword() == null){
        System.out.println("Client not found in " + getBankName() + "database");
            return false;
        }

        System.out.println(client.toString() + " connected to bank succesfully");

        return true;
    }

    @Override
    public ArrayList<BankAccount> getAccounts(Client c) throws RemoteException {
       System.out.println("WORKED");
       return null;
    }
}

Interface implemented by Bank Class:

public interface IBank extends Remote{

    String getURL() throws RemoteException;

    String getBankName() throws RemoteException;

    boolean checkClient(String Username, String Password) throws RemoteException;

    ArrayList<BankAccount> getAccounts(Client c) throws RemoteException;
}

Serializable object used by Bankmethod:

public class BankAccount implements Serializable {

}

*above examples are just pieces of the complete application

I can't figure out why the 'checkClient' method works just fine, and the getAccounts (and other methods not included in code above) give the UnmarshalException.

Any help will be greatly appreciated

EXAMPLE

Below you can find the method I use to connect a Client to a Bank:

@Override
public

ArrayList<BankAccount> connectToBank(Client c) throws RemoteException {
    assert(c != null);

    ArrayList<BankAccount> accounts;        

    if(!Bank.checkClient(c.Username, c.Password)){
        System.out.println("bank.checkclient == false, Client not found");
        return null;
    } else {
        System.out.println("Client found in " + Bank.getBankName() + " database");
    }

    System.out.println("Calling bank.getaccounts");
    accounts = Bank.getAccounts(c);

    if(accounts == null){
        System.out.println("No accounts found for " + c.Username);
    }

    return accounts;        
}

When I use a username and password that doesn't exist, console prints out:

Server IP Address: localhost
Server Port number 9000
Client: Registry located
Client: Bank and Publisher are bound
bank.checkclient == false, Client not found

and returns null;

However when I use a username and password that does exist, console prints out:

Server IP Address: localhost
Server Port number 9000
Client: Registry located
Client: Bank and Publisher are bound
Client found in RABO database
Calling bank.getaccounts
Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
    at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1774)
    at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1657)
    at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
    at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
    at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
    at javafx.event.Event.fireEvent(Event.java:198)
    at javafx.scene.Node.fireEvent(Node.java:8411)
    at javafx.scene.control.Button.fire(Button.java:185)
    at com.sun.javafx.scene.control.behavior.ButtonBehavior.keyReleased(ButtonBehavior.java:136)
    at com.sun.javafx.scene.control.behavior.ButtonBehavior.callAction(ButtonBehavior.java:106)
    at com.sun.javafx.scene.control.behavior.BehaviorBase.callActionForEvent(BehaviorBase.java:218)
    at com.sun.javafx.scene.control.behavior.BehaviorBase.lambda$new$74(BehaviorBase.java:135)
    at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
    at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
    at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
    at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
    at javafx.event.Event.fireEvent(Event.java:198)
    at javafx.scene.Scene$KeyHandler.process(Scene.java:3964)
    at javafx.scene.Scene$KeyHandler.access$1800(Scene.java:3910)
    at javafx.scene.Scene.impl_processKeyEvent(Scene.java:2040)
    at javafx.scene.Scene$ScenePeerListener.keyEvent(Scene.java:2501)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:197)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.run(GlassViewEventHandler.java:147)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleKeyEvent$353(GlassViewEventHandler.java:228)
    at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleKeyEvent(GlassViewEventHandler.java:227)
    at com.sun.glass.ui.View.handleKeyEvent(View.java:546)
    at com.sun.glass.ui.View.notifyKey(View.java:966)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
    at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
    at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1771)
    ... 49 more
Caused by: java.rmi.ServerException: RemoteException occurred in server thread; nested exception is: 
    java.rmi.UnmarshalException: unrecognized method hash: method not supported by remote object
    at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:354)
    at sun.rmi.transport.Transport$1.run(Transport.java:200)
    at sun.rmi.transport.Transport$1.run(Transport.java:197)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.Transport.serviceCall(Transport.java:196)
    at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:568)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:826)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$256(TCPTransport.java:683)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:682)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
    at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(StreamRemoteCall.java:276)
    at sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:253)
    at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:162)
    at java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(RemoteObjectInvocationHandler.java:227)
    at java.rmi.server.RemoteObjectInvocationHandler.invoke(RemoteObjectInvocationHandler.java:179)
    at com.sun.proxy.$Proxy7.getAccounts(Unknown Source)
    at Client.Client.connectToBank(Client.java:240)
    at Client.FXMLClientController.btnLogIn_clicked(FXMLClientController.java:232)
    ... 59 more
Caused by: java.rmi.UnmarshalException: unrecognized method hash: method not supported by remote object
    at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:294)
    at sun.rmi.transport.Transport$1.run(Transport.java:200)
    at sun.rmi.transport.Transport$1.run(Transport.java:197)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.Transport.serviceCall(Transport.java:196)
    at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:568)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:826)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$256(TCPTransport.java:683)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:682)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    ... 1 more

So you can see the Bank.checkClient works fine, the Bank.getAccounts causes the problem

Answer 1

You've changed something about the remote interface without recompiling and redeploying everything. Do a clean build, redeploy, retest.

Answer 2

I still haven't figured out the exact problem, however the problem occured exclusively when I was trying to send a custom object via RMI. Methods that return String, boolean, int etc. from the Bank worked fine. When I tried sendig a BankAccount (customobject) the problem occured.

I fixed it with merging the Client-project and the Bank-project together, now they use the exact same Interfaces and Classes so the Unmarshal-problem went away

hope this helps someone