Как запустить и вызвать сервлет из Android Studio 3.2.1

Question

Я пытаюсь вызвать и запустить сервлет из моего маленького проекта на Android Studio (v 3.2.1).Проблема в том, что я не могу запустить сервлет, который я вызываю, когда я использовал AsyncTask ...

Я видел десятки уроков и видео, но ничегопохоже, работает, а сервлет даже не запускается, используя метод execute (полный путь сервлета).

public class MainActivity extends AppCompatActivity {
Button goToProfile;
private Intent i;
ProgressBar bar;
STUDENTI u;
@Override
 protected void onCreate(Bundle savedInstanceState) {
   requestWindowFeature(Window.FEATURE_NO_TITLE);
   getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
   super.onCreate(savedInstanceState);
   setContentView(R.layout.activity_main);
   i = new Intent(getApplicationContext(), profilo.class);
   i.putExtra("studente", u);
   goToProfile= findViewById(R.id.login);
   goToProfile.setOnClickListener(new View.OnClickListener() {
       @Override
       public void onClick(View v) {
          // startActivity(i);
          ProvaRichiesta r= new ProvaRichiesta();
          r.execute("http://localhost:8080/PROGETTO_TWEB/ControllerANDROID");
       }
   });
}


class ProvaRichiesta extends AsyncTask<String,Void,String> {
HttpURLConnection connection = null;
BufferedReader reader = null;
String result=" ";
String line=" ";
String risp = " ";
EditText user;
EditText password;
String login ="";

@Override
protected void onPreExecute() {
       super.onPreExecute();
       user = (EditText) findViewById(R.id.username);
       password = (EditText) findViewById(R.id.password);
       bar = (ProgressBar)findViewById(R.id.progressbar);
       bar.setVisibility(View.VISIBLE);
       goToProfile.setEnabled(false);
       if(user != null &&  user.length()!= 0 && password != null && password.length()!= 0) {
           login = "login:" + user.getText() + ":" + password.getText();
       }else {
           Toast.makeText(getApplicationContext(), "compila tutti i campi", Toast.LENGTH_LONG).show();
       }
}

@Override
protected String doInBackground(String... params) {
   try {
       String richiesta = "?azione=" + login;
       URL url = new URL(params[0] + richiesta);
       result=makeHTTPrequest(url);
   } catch (IOException e) {
       System.out.println(e.getMessage());
   }
   return result;
}
public String makeHTTPrequest(URL url) throws IOException {
   String jsonResponse = "";
   InputStream inputStream = null;
   try {
       connection = (HttpURLConnection) url.openConnection();
       connection.setRequestMethod("GET");
       connection.setDoInput(true);
       connection.connect();
       inputStream = connection.getInputStream();
       System.out.println("-----------------------------------"+inputStream);
       jsonResponse = readFromStream(inputStream);
   } catch (IOException e) {
   } finally {
       if (connection != null) {
           connection.disconnect();
       }
       if (inputStream != null) {
           inputStream.close();
       }
   }
   return jsonResponse;
}

   private String readFromStream(InputStream inputStream)throws IOException {
       StringBuilder output = new StringBuilder();
       if (inputStream != null) {
           InputStreamReader inputStreamReader = new InputStreamReader(inputStream, Charset.forName("UTF-8"));
           BufferedReader reader = new BufferedReader((inputStreamReader));
           String line = reader.readLine();
           while (line != null) {
               output.append(line);
               line = reader.readLine();
           }
       }
       return output.toString();
   }


   @Override
    protected void onPostExecute(String s) {
   super.onPostExecute(s);
   JSONObject obj;
   JSONArray array;
       bar.setVisibility(View.INVISIBLE);
       goToProfile.setEnabled(true);
   try {
       array = new JSONArray(result);
       risp = array.getJSONObject(0).getString("risposta");
       if (risp.equals("no")) {
           Toast.makeText(getApplicationContext(), "username o password scorretti", Toast.LENGTH_SHORT).show();
       } else {
           obj = array.getJSONObject(1);
           u.setUSERNAME(obj.getString("nomeUtente"));
           u.setSTUDENTE_PPW(obj.getString("password"));
           u.setRUOLO(obj.getString("ruolo"));
           startActivity(i);
       }
   } catch (JSONException e) {
       System.out.println(e.getMessage());
   }
}
}
}