Java send email through gmail, sometimes works sometimes hang - spring

Question

I am sending email by Gmail through my web app.
However, sometimes it is working fine but sometimes it just stop without any message.
Does anyone know how to solve this?
In my spring AppConfig.java
#Bean
public JavaMailSender getMailSender(){
JavaMailSenderImpl mailSender = new JavaMailSenderImpl();
mailSender.setHost("smtp.gmail.com");
mailSender.setPort(587);
mailSender.setUsername("my email from");
mailSender.setPassword("my email password");
Properties javaMailProperties = new Properties();
javaMailProperties.put("mail.smtp.starttls.enable", "true");
javaMailProperties.put("mail.smtp.auth", "true");
//javaMailProperties.put("mail.transport.protocol", "smtps");
javaMailProperties.put("mail.transport.protocol", "smtp");
javaMailProperties.put("mail.debug", "true");
mailSender.setJavaMailProperties(javaMailProperties);
return mailSender;
}
In my mailService.java
public void sendEmailWithTemplate(Activity activity, Object object) {
Member member = (Member) object;
MimeMessagePreparator verificationEmail = getEmailFromActivity(activity, member);
try {
mailSender.send(verificationEmail);
System.out.println("Message sent.............................");
} catch (MailException ex) {
System.err.println(ex.getMessage());
}
}
private MimeMessagePreparator getEmailFromActivity(final Activity activity, final Member member) {
MimeMessagePreparator preparator = new MimeMessagePreparator() {
public void prepare(MimeMessage mimeMessage) throws Exception {
MimeMessageHelper helper = new MimeMessageHelper(mimeMessage, true);
helper.setSubject(activity.getActivity_subject());
helper.setFrom("my from email");
helper.setTo(member.getEmail());
String mailContent = activity.getActivity_content();
helper.setText(mailContent, true);
}
};
return preparator;
}
Sometimes its working fine and I will be able to send the mail, but sometime is just stop for more than 20 minutes at:
DEBUG SMTP: enable SASL
DEBUG SMTP: useEhlo true, useAuth false
DEBUG SMTP: trying to connect to host "smtp.gmail.com", port 587, isSSL false

Answer 1

This is the method I get from other post, but I can't look back the post.
Activity is one of my object storing the subject and content.
public void sendEmailWithActivity(Activity activity, Object object, String path) {
try {
Member member = (Member) object;
String host = "smtp.gmail.com";
String username = "email";
String password = "password";
String body = activity.getActivity_content();
String name = activity.getActivity_name();
String subject = activity.getActivity_subject();=
//Set the properties
Properties props = new Properties();
props.put("mail.smtps.auth", "true");
// Set the session here
Session session = Session.getDefaultInstance(props);
MimeMessage msg = new MimeMessage(session);
// set the message content here
msg.setSubject(subject);
msg.setContent(body, "text/html");
msg.setFrom(new InternetAddress(username));
msg.addRecipient(Message.RecipientType.TO,
new InternetAddress(member.getEmail()));
Transport t = session.getTransport("smtps");
t.connect(host, username, password);
t.sendMessage(msg, msg.getAllRecipients());
t.close();
} catch (Exception e) {
e.printStackTrace();
} finally {
}
}