Properties props = System.getProperties();
props.put("mail.smtp.host", MailHost);
props.put("mail.smtp.auth", "true");
Session session_m = Session.getInstance(props,  null );
subject = "Тема";
message =  new  MimeMessage (session_m);
message.setFrom ( new  InternetAddress("from@mail.ru","username"));
message.addRecipient(Message.RecipientType.TO,  new  InternetAddress(emailUser, fullnameUser));
message.setSubject(subject);
message.setText("Text");
message.setHeader("Content-Type","text/plain;charset=windows-1251");
SMTPTransport t = (SMTPTransport)session_m.getTransport("smtp");
t.connect(MailHost, "username", "pass");
t.sendMessage(message, message.getAllRecipients());