Server with Multiple Clients - JAVA

Given the two codes , one for the server and the other one for the client , i am trying to make multiple clients communicate with the server but i don't have a clue how to do it. Any idea how the server can recognize the client who spoke to him and reply back to the same client ?

Server:

    import java.io.*;
    import java.net.*;
    public class Provider{
    ServerSocket providerSocket;
    Socket connection = null;
    ObjectOutputStream out;
    ObjectInputStream in;
    String message;
    Provider(){}
    void run()
{
    try{
        //1. creating a server socket
        providerSocket = new ServerSocket(2004, 10);
        //2. Wait for connection
        System.out.println("Waiting for connection");
        connection = providerSocket.accept();
        System.out.println("Connection received from " + connection.getInetAddress().getHostName());
        //3. get Input and Output streams
        out = new ObjectOutputStream(connection.getOutputStream());
        out.flush();
        in = new ObjectInputStream(connection.getInputStream());
        sendMessage("Connection successful");

        //4. The two parts communicate via the input and output streams
        do{
            try{
                message = (String)in.readObject();

                System.out.println("client>" + message);
                if (message.equals("byee"))
                    sendMessage("Wosil");
            }
            catch(ClassNotFoundException classnot){
                System.err.println("Data received in unknown format");
            }
        }while(!message.equals("bye"));
    }
    catch(IOException ioException){
        ioException.printStackTrace();
    }
    finally{
        //4: Closing connection
        try{
            in.close();
            out.close();
            providerSocket.close();
        }
        catch(IOException ioException){
            ioException.printStackTrace();
        }
    }
}
void sendMessage(String msg)
{
    try{
        out.writeObject(msg);
        out.flush();
        System.out.println("Zame-Server>" + msg);
    }
    catch(IOException ioException){
        ioException.printStackTrace();
    }
}
public static void main(String args[])
{
    Provider server = new Provider();
    while(true){
        server.run();
        }
    }
}

Client

import java.io.*;
import java.net.*;
public class Requester{
Socket requestSocket;
ObjectOutputStream out;
ObjectInputStream in;
String message;
Requester(){}
void run()
{
    try{
        //1. creating a socket to connect to the server
        requestSocket = new Socket("localhost", 2004);
        System.out.println("Connected to localhost in port 2004");
        //2. get Input and Output streams
        out = new ObjectOutputStream(requestSocket.getOutputStream());
        out.flush();
        in = new ObjectInputStream(requestSocket.getInputStream());
        //3: Communicating with the server

                sendMessage("Hi my server");
                sendMessage("SENDING");
                message = "byee";
                sendMessage(message);
        do{
            try{
                message = (String)in.readObject();
                System.out.println("server>" + message);


            }
            catch(ClassNotFoundException classNot){
                System.err.println("data received in unknown format");
            }
        }while(!message.equals("bye"));
    }
    catch(UnknownHostException unknownHost){
        System.err.println("You are trying to connect to an unknown host!");
    }
    catch(IOException ioException){
        ioException.printStackTrace();
    }
    finally{
        //4: Closing connection
        try{
            in.close();
            out.close();
            requestSocket.close();
        }
        catch(IOException ioException){
            ioException.printStackTrace();
        }
    }
}
void sendMessage(String msg)
{
    try{
        out.writeObject(msg);
        out.flush();
        System.out.println("Zame-Client>" + msg);
    }
    catch(IOException ioException){
        ioException.printStackTrace();
    }
}
public static void main(String args[])
{
    Requester client = new Requester();
    client.run();
}
}