مشکل در ارسال پارامتر در پروژه اندروید مارکت

سلام دوستان وقت بخیر . کدها رو کپی میکنم و خطا ها رو مشخص میکنم. ممنون میشم کمک کنید.

public static void populateFromServer() {
  String url = "http://android1-apps.esy.es/service.php";

  Map<String,String> params = new HashMap<>();
  params.put("action", "read");
  params.put("filter", lastFilter);
  params.put("sort", lastSort);

  WebService webService=new WebService();

  String result= webService.execute(params);   error: incompatible types: AsyncTask<Map<String,String>,Void,String> cannot be converted to String

  if (result != null) {
    try {
      applications.clear();
      JSONArray apps = new JSONArray(result);
      for (int i = 0; i < apps.length(); i++) {
        JSONObject object = apps.getJSONObject(i);
        StructApplication application = new StructApplication();

        application.name = object.getString("name");
        application.price = object.getInt("price");
        application.logoUrl = object.getString("logoUrl");
        application.ratingValue = (float) object.getDouble("ratingValue");
        application.author = object.getString("author");
        application.votes = object.getInt("votes");
        application.file = object.getString("file");
        application.fileSize = object.getLong("fileSize");
        application.versionName = object.getString("versionName");
        application.installs = object.getInt("installs");
        application.description = object.getString("description");
        application.phoneNumber = object.getString("phoneNumber");
        application.email = object.getString("email");

        applications.add(application);
      }

      adapter.notifyDataSetChanged();
    }
    catch (JSONException e) {
      e.printStackTrace();
    }
  }
}
private static class WebService extends AsyncTask<Map<String,String>,Void,String> {


  @Override
  protected String doInBackground(Map<String,String>... params) {
    String encodedStr = getEncodedData(params);  error: incompatible types: Map<String,String>[] cannot be converted to Map<String,String>

    BufferedReader reader = null;

    try {

      URL url = new URL("http://android1-apps.esy.es/service.php");
      HttpURLConnection con = (HttpURLConnection) url.openConnection();

      con.setRequestMethod("POST");
      con.setDoOutput(true);
      OutputStreamWriter writer = new OutputStreamWriter(con.getOutputStream());
      writer.write(encodedStr);
      writer.flush();

      StringBuilder sb = new StringBuilder();
      reader = new BufferedReader(new InputStreamReader(con.getInputStream()));

      String line;
      while ((line = reader.readLine()) != null) {
        sb.append(line + "\n");
      }
      line = sb.toString();

      return line;

    } catch (Exception e) {
      e.printStackTrace();
    } finally {
       if (reader != null) {
         try {
           reader.close();
         } catch (IOException e) {
           e.printStackTrace();
         }
       }
     }
  return null;
 }

  @Override
  protected void onPostExecute(String s) {
    super.onPostExecute(s);
  }

  private String getEncodedData(Map<String,String> data) {
    StringBuilder sb = new StringBuilder();
    for(String key : data.keySet()) {
      String value = null;
      try {
        value = URLEncoder.encode(data.get(key),"UTF-8");
      } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
      }

      if(sb.length()>0)
        sb.append("&");

      sb.append(key + "=" + value);
    }
    return sb.toString();
  }

}