code: public Reader requestPost(String data) throws IOException {
  
          connection.setRequestMethod("POST");
          connection.setDoOutput(true);
  
          Writer writer = new Writer(connection.getOutputStream());
          writer.write(data);
          writer.close();
  
          return new Reader(connection.getInputStream());
      }
docs: Do a HTTP POST request forward specified URL and data string.
  Creates and return Reader object.
  
  @param data
  The data string that the request will contain.
  
  @throws IOException
  If an I/O error occurs while writing data on the request or
  creating the Reader object.