code: public static void deliverMail (String[] recipients, String sender,
                                      String subject, String body)
          throws IOException
      {
          deliverMail(recipients, sender, subject, body, null, null);
      }
docs: Delivers the supplied mail message using the machine's local mail
  SMTP server which must be listening on port 25. If the
  <code>mail.smtp.host</code> system property is set, that will be
  used instead of localhost.
  
  @exception IOException thrown if an error occurs delivering the
  email. See {@link Transport#send} for exceptions that can be thrown
  due to response from the SMTP server.