if(action.equals("buy")){
                String to = (String)session.getAttribute("user");
                 //Get the session object
                Properties props = new Properties();
                props.put("mail.smtp.host", "smtp.gmail.com");
                props.put("mail.smtp.socketFactory.port", "465");
                props.put("mail.smtp.socketFactory.class",
                          "javax.net.ssl.SSLSocketFactory");
                props.put("mail.smtp.auth", "true");
                props.put("mail.smtp.port", "465");

                Session session2 = Session.getInstance(props,
                 new javax.mail.Authenticator() {
                 protected PasswordAuthentication getPasswordAuthentication() {
                 return new PasswordAuthentication("henri.tuan77@gmail.com","Dumbledore77");//change accordingly
                 }
                });

                //compose message
                try {
                 MimeMessage message = new MimeMessage(session2);
                 message.setFrom(new InternetAddress("henri.tuan77@gmail.com"));//change accordingly
                 message.addRecipient(Message.RecipientType.TO,new InternetAddress(to));
                 message.setSubject("Hello");
                 message.setText("Testing.......");

                 //send message
                 Transport.send(message);

                 System.out.println("message sent successfully");

                } catch (MessagingException e) {
                    throw new RuntimeException(e);
                }

            }