Socket client Serveur Tcp Sous java

Bonjour tout le monde ,

j'ai écrit deux processus client / serveur : ( je travail avec le netbeans )

le client envoie un message vers le serveur et le serveur aussi , mais le problème c'est que je ne reçois pas les message envoyer parle le client , il m affiche ce message
run:
Attempting to connect to 127.0.0.1:9990
Connection Established
Response from server:
3.000.000.12.136W
Cannot establish connection. Server may not be up.Connection reset
BUILD SUCCESSFUL (total time: 0 seconds)

je vous laisse avec mon code et merci de me signaler l'erreur :)

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Coté serveur :

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import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.ServerSockeimportt;
import java.net.Socket;

public class SocketServer {

public ServerSocket serverSocket;
public int port;

public SocketServer(int port) {
this.port = port;
}

public void start() throws IOException {
System.out.println("Starting the socket server at port:" + port);
serverSocket = new ServerSocket(port);

//Listen for clients. Block till one connects

System.out.println("Waiting for clients...");
Socket client = serverSocket.accept();

//A client has connected to this server. Send welcome message
sendWelcomeMessage(client);
}

public void sendWelcomeMessage(Socket client) throws IOException {
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(client.getOutputStream()));
writer.write("3.000.000.12.136W");
writer.write("\n"); // shown separately for clarity
writer.flush();
}

/**
* Creates a SocketServer object and starts the server.
*
* @param args
*/
public static void main(String[] args) {
// Setting a default port number.
int portNumber = 9990;

try {
// initializing the Socket Server
SocketServer socketServer = new SocketServer(portNumber);
socketServer.start();

} catch (IOException e) {
e.printStackTrace();
}
}
}

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Coté Client :

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import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;


public class SocketClient {

public String hostname;import
public int port;
Socket socketClient;

public SocketClient(String hostname, int port){
this.hostname = hostname;
this.port = port;
}

public void connect() throws UnknownHostException, IOException{
System.out.println("Attempting to connect to "+hostname+":"+port);
socketClient = new Socket(hostname,port);
System.out.println("Connection Established");
}

public void readResponse() throws IOException{
String userInput;
BufferedReader stdIn = new BufferedReader(new InputStreamReader(socketClient.getInputStream()));

System.out.println("Response from server:");
while ((userInput = stdIn.readLine()) != null) {
System.out.println(userInput);
}}



public void sendResponse() throws IOException{
PrintWriter pred = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socketClient.getOutputStream())),true);
String str = "22.000..B..";
pred.println(str);
System.out.println("the message was sent to the server");
}

public static void main(String arg[]){
//Creating a SocketClient object
SocketClient client = new SocketClient ("127.0.0.1",9990);
try {
//trying to establish connection to the server
client.connect();
//if successful, read response from server
client.readResponse();
//
client.sendResponse();

} catch (UnknownHostException e) {
System.err.println("Host unknown. Cannot establish connection");
} catch (IOException e) {
System.err.println("Cannot establish connection. Server may not be up."+e.getMessage());
}
}
}