code: @Override
      public void acknowledge(SQSMessage message) throws JMSException {
          session.checkClosed();
          amazonSQSClient.deleteMessage(new DeleteMessageRequest(
                  message.getQueueUrl(), message.getReceiptHandle()));
          unAckMessages.remove(message.getReceiptHandle());
      }
docs: Acknowledges the consumed message via calling <code>deleteMessage</code>.