RMI NotSerializableException although it's a remote object

Question

I'm writing a small RMI based Chat application. The idea is: the Client registers himself on the Server, and everytime the server receives a message from a client, he pushes this message to all other clients. But I receive a NotSerializableException although, the object, I'm passing as a method parameter implements the Remote interface. Here is some code: (The problematic part is the `this` parameter in `this.chatServ.registriereClient(this);` (ClientChat Implementation)) The (ClientChat)interface: ``` public interface ChatClient extends Remote { } ``` (ClientChat)Implementation: ``` public class ChatClientImpl implements ChatClient { ChatServer chatServ; String clientName; public ChatClientImpl(String clientName, ChatServer chatServ) { this.chatServ = chatServ; this.clientName = clientName; try { this.chatServ.registriereClient(this); } catch (RemoteException e) { e.printStackTrace(); } } } ``` (ServerChat) Interface ``` public interface ChatServer extends Remote { void registriereCl…

Accepted Answer

Objects passed as parameters or results of remote methods must be either:

Serializable (or Externalizable), or

Exported remote objects.

Yours is neither. However as it implements a Remote interface clearly you intended (2). Objects that extend `UnicastRemoteObject` are auto-exported on construction. Objects that don't must be exported explicitly, via `UnicastRemoteObject.exportObject()`.

RMI NotSerializableException although it's a remote object

Solution

Problem