Java chat, sockets, cliente/servidor... n funciona

Front-end
#1

//servidor
import java.io.;
import java.net.;
public class Servidor{
public ServerSocket server;
public Socket sock;
public DataInputStream in;
public DataOutputStream out;
public Servidor(){
try{
this.server = new ServerSocket(8080);
this.sock = this.server.accept();
this.in = new DataInputStream(sock.getInputStream());
this.out = new DataOutputStream(sock.getOutputStream());
}
catch(IOException e){
System.out.println(e.getMessage());
}
}
public static void main(String args[]){
try{
Servidor serv = new Servidor();
int valor = serv.in.readInt();
String texto = serv.in.readUTF();
System.out.println(valor);
System.out.println(texto);
serv.out.writeInt(6000);
serv.out.writeUTF(“Olá - Socket Servidor.”);
serv.in.close();
serv.out.close();
serv.sock.close();
serv.server.close();
}
catch(IOException e){
System.out.println(e.getMessage());
}
}
}

//cliente

import java.io.;
import java.net.;
public class Cliente{
public Socket client;
public DataInputStream in;
public DataOutputStream out;
public Cliente(){
try{
this.client = new Socket(“127.0.0.1”,8080);
this.in = new DataInputStream(client.getInputStream());
this.out = new DataOutputStream(client.getOutputStream());
}
catch(IOException e){
System.out.println(e.getMessage());
}
}
public static void main(String args[]){
try{
Cliente cli = new Cliente();
cli.out.writeInt(3000);
cli.out.writeUTF(“Olá - Socket Cliente.”);
int valor = cli.in.readInt();
String texto = cli.in.readUTF();
System.out.println(valor);
System.out.println(texto);
cli.in.close();
cli.out.close();
cli.client.close();
}
catch(IOException e){
System.out.println(e.getMessage());
}
}
}

#2