This question is 5 1/2 years old, but has not been answered or closed. That is why I am writing this assuming that the questionnaire stands for Server-Client-Model .

I would recommend checking out NetCom2 . It is an easy-to-use framework that supports high modularity for future enhancements.

The concept of this structure may seem rather odd since it is built as an "over-network" Event-Bus . Communication consists mainly of objects flying over the network and responding to it Servers / Clients.

On the server, you have to write a java program that looks like this:

public class ServerMain {

    private ServerStart serverStart;

    public ServerMain(int port) {
        serverStart = ServerStart.at(port);
    }

    public void start() throws StartFailedException, ClientConnectionFailedException {
        serverStart.launch();
        serverStart.acceptAllNextClients();
    }
}

      

        
        
        
      

    

And the potential Client will look like this:

public class ClientMain {

    private ClientStart clientStart;

    public ClientMain(String address, int port) {
        clientStart = ClientStart.at(adress, port);
    }

    public void start() throws StartFailedException {
        clientStart.launch();
    }
}

      

        
        
        
      

    

This is how you create and run the server and client.
You can tell both the client and the server how to react to certain objects. This must be done before [clientStart / serverStart] .launch (), specifying:

clientStart.getCommunicationRegistration()
           .register(MessageObject.class)
           .addFirst(messageObject -> System.out.println(messageObject));

serverStart.getCommunicationRegistration()
           .register(MessageObject.class)
           .addFirst((session, messageObject) -> session.send(messageObject));

      

        
        
        
      

    

Now you can send something from the Client to the Server by specifying:

clientStart.send(new MessageObject());

      

        
        
        
      

    

This example is basically an echo server which is explained here .
The connection between them can be found in more detail here or here .

If you are overwhelmed by the output being produced, you can adjust it by specifying:

// Choose only one.
NetComLogging.setLogging(Logging.trace());
NetComLogging.setLogging(Logging.debug());
NetComLogging.setLogging(Logging.info());
NetComLogging.setLogging(Logging.warn());
NetComLogging.setLogging(Logging.error());
NetComLogging.setLogging(Logging.disabled());

      

        
        
        
      

    

This is explained in more detail here .

NOTINGS

Please note that this project has just ended and the documentation is still ongoing.

Also note that this framework is still in beta testing. I would not recommend it for production use, but I would look at it for personal use.