Re: sendmail.jsp: How do I know that mail was send ?

I have a small form on my web page with which the visitors send me a
comment.

In sendmail.jsp it was written:
...
<%
   SendMail sendMail = new SendMail();
   sendMail.sendMail(to, from, subject, content, "localhost");

%>
...
to, from, subject, content
pokupim iz html forme.

sendMail method in SendMail class looks like this:

   public static void sendMail(String to, String from, String subject,
String content, String host) throws Exception {
       // create some properties and get the default Session

       host = "localhost";

       Properties props = new Properties();
       props.put("mail.smtp.host", host);

       Session session = Session.getDefaultInstance(props, null);

       try {
           // create a message
           MimeMessage msg = new MimeMessage(session);
           msg.setFrom(new InternetAddress(from));
  msg.setHeader("Content-Type", "text/plain; charset=windows-1250");
           InternetAddress[] address = {new InternetAddress(to)};
           msg.setRecipients(Message.RecipientType.TO, address);
           msg.setSubject(subject,"windows-1250");
  //msg.setHeader("Content-Transfer-Encoding", "8bit");

           msg.setSentDate(new Date());
           // If the desired charset is known, you can use
           // setText(text, charset)
           //msg.setText(content,"Cp1250");
           msg.setText(content,"windows-1250");

           Transport.send(msg);
       } catch (MessagingException mex) {
           System.out.println("\n--Exception handling in
msgsendsample.java");

           mex.printStackTrace();
           System.out.println();
           Exception ex = mex;
           do {
               if (ex instanceof SendFailedException) {
                   SendFailedException sfex = (SendFailedException)ex;
                   Address[] invalid = sfex.getInvalidAddresses();
                   if (invalid != null) {
                       System.out.println(" ** Invalid Addresses");
                       if (invalid != null) {
                           for (int i = 0; i < invalid.length; i++)
                               System.out.println(" " +
invalid[i]);
                       }
                   }
                   Address[] validUnsent = sfex.getValidUnsentAddresses();
                   if (validUnsent != null) {
                       System.out.println(" ** ValidUnsent Addresses");
                       if (validUnsent != null) {
                           for (int i = 0; i < validUnsent.length; i++)
                               System.out.println("
"+validUnsent[i]);
                       }
                   }
                   Address[] validSent = sfex.getValidSentAddresses();
                   if (validSent != null) {
                       System.out.println(" ** ValidSent Addresses");
                       if (validSent != null) {
                           for (int i = 0; i < validSent.length; i++)
                               System.out.println("
"+validSent[i]);
                       }
                   }
               }
               System.out.println();
               if (ex instanceof MessagingException)
                   ex = ((MessagingException)ex).getNextException();
               else
                   ex = null;
           } while (ex != null);
       }
   }

Code above send mail successfully if the visitor wrote "from" mail
correctly. But if the visitor leave "from field" empty or put some wrong
mail I need to send him/her a message about un/success sending of comment
to me. How to do it ?