How can I resolve the error 'No Provider for smtp'.

My OS is WindowsNT workstation.

I can send mail correctly by outlook using my company's SMTP host.

and I can send mail by postmail.exe and windmail.exe
using that SMTP host.

but I can't send mail by JavaMail using that SMTP host.
I alway be told 'No Provider for smtp' error.


The follow is my program.

...

Properties props = System.getProperties();

props.put("mail.smtp.host", "XXX.XXX.XXX.XXX");


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

MimeMessage msg = new MimeMessage(session);

msg.setFrom(new InternetAddress("xxx", "xxx@xxx.xxx"));

msg.setRecipient(Message.RecipientType.TO,
new InternetAddress("xxx@xxx.xxx"));

...

Transport transport = session.getTransport("smtp");

transport.connect(host,25, null, null);

transport.send(msg);

...




Even if I use yahoo POP3 & SMTP host,

I were told "No Provider for pop3" error too.


String smtpHost = "smtp.mail.yahoo.com";

String popHost = "pop.mail.yahoo.com";