code: @Override
      public void handleRequest(final InputStream input, final OutputStream output, final Context context) throws IOException {
          byte[] serializedSpeechletRequest = IOUtils.toByteArray(input);
          final AlexaSpeechlet speechlet = AlexaSpeechletFactory.createSpeechletFromRequest(serializedSpeechletRequest, getSpeechlet(), getUtteranceReader());
          final SpeechletRequestHandler handler = getRequestStreamHandler();
          try {
              byte[] outputBytes = handler.handleSpeechletCall(speechlet, serializedSpeechletRequest);
              output.write(outputBytes);
          } catch (SpeechletRequestHandlerException | SpeechletException e) {
              // wrap actual exception in expected IOException
              throw new IOException(e);
          }
      }
docs: The handler method is called on a Lambda execution.
  @param input the input stream containing the Lambda request payload
  @param output the output stream containing the Lambda response payload
  @param context a context for a Lambda execution.
  @throws IOException exception is thrown on invalid request payload or on a provided speechlet
  handler having no public constructor taking a String containing the locale