Socket in Java that sends and receives

One note: A client-server application in which the two send and receive messages is typically multi-threaded, has no other output. First follow the server code. It is a console application that sends and receives messages to a client. A serverSocket is created on a particular port and is waiting for a connection. After the connection the application becomes multithreaded. The loop inside the constructor reads strings from the console and sends them to the client. The run method loop reads the client strings and prints them to the console.

import java.net.*;
import java.io.*;
import java.net.*;
import java.util.Scanner;

class SrvThread extends Thread {
    ServerSocket serverSocket = null;
    Socket socket = null;
    static DataOutputStream ostream = null;
    static int port = 9090;//porta para comunicacao.
    DataInputStream istream  = null;
    String MRcv= "";
    static String MSnd= "";

    SrvThread(){
    try {
        serverSocket = new ServerSocket(port);
        System.out.println("Aguardando conexão...");
        socket = serverSocket.accept();//aguarda conexao com o cliente.
        System.out.println("Conexão Estabelecida.");
        ostream = new DataOutputStream(socket.getOutputStream());
        istream = new DataInputStream(socket.getInputStream());

        this.start();//inicia uma nova thread. O metodo run é executado.

        Scanner console = new Scanner(System.in);
        while(true){
            System.out.println("Mensagem: ");
            String MSnd = console.nextLine(); //le string do console
            ostream.writeUTF(MSnd);//envia string para o cliente.
            ostream.flush();
       }
    } catch(Exception e){
          System.out.println(e);
      }
  }

  public void run(){
      try {
          while(true){
              MRcv = istream.readUTF();//le as strings do cliente
              System.out.println("Remoto: "+MRcv);
          }
      } catch(Exception e) {
          System.out.println(e);
      }
  }

  public static void main(String args[]){
    new SrvThread();
  }
}

Follow the client code. A client socket is created with the host and port as a parameter. NOTE: The port must be the same as that used on the server. The rest of the code is similar to the server code.

import java.net.*;
import java.io.*;
import java.util.Scanner;

public class CliThread extends Thread {

    static DataOutputStream ostream = null;
    DataInputStream istream = null;
    static String host = "";
    static int port = 9090;//porta para comunicacao. Deve ser a mesma do servidor.
    Socket socket = null;
    String MRcv= "";
    static String MSnd= "";


    CliThread(){
        try {
            socket = new Socket("localhost", port);//conecta com o servidor.
            System.out.println("Conectado....");
            this.start();//comeca uma nova thread. O metodo run é executado.
            ostream = new DataOutputStream(socket.getOutputStream());
            istream = new DataInputStream(socket.getInputStream());
            Scanner console = new Scanner(System.in);

            while(true){
                System.out.println("Mensagem: ");
                String MSnd = console.nextLine();//le mensagem do console.
                ostream.writeUTF(MSnd);//manda mensagem para o servidor.
                ostream.flush();
            }
        } catch(Exception e) {System.out.println(e);}
  }

  public void run(){
      while (true) {
          try {        
              MRcv = istream.readUTF();//le mensagem do servidor.
              System.out.println("Remoto: " + MRcv);
          } catch(Exception e) {}
      }
  }


  public static void main(String args[]){
      new CliThread(); 
  }
}