What protocol is this function using to connect?

Question

try{
               kin = new BufferedReader(new InputStreamReader(System.in));
               s = new Socket("127.0.0.1",9191);
               dos = new DataOutputStream(s.getOutputStream());
dis = new DataInputStream(s.getInputStream());
System.out.print(dis.readUTF());//connected
System.out.print(dis.readUTF());//user
dos.writeUTF(kin.readLine());dos.flush();
System.out.print(dis.readUTF());//pass
dos.writeUTF(kin.readLine());dos.flush();
String z="";
               BufferedWriter out = new BufferedWriter(fstream);
while (true){
     System.out.print(dis.readUTF());//xml msl
          }catch(Exception e){
               e.printStackTrace();
          }

Answer 1

TCP -Transmission Control Protocol