code: public void acceptSentTransport(Transport transport) {
          if (transport instanceof com.sun.mail.smtp.SMTPTransport) {
              final com.sun.mail.smtp.SMTPTransport smtp = (com.sun.mail.smtp.SMTPTransport) transport;
              lastReturnCode = smtp.getLastReturnCode();
              lastServerResponse = smtp.getLastServerResponse();
          }
      }
docs: ==================