Sending emails with Java using Gmail SMTP

Other Questions Gmail
1 
Hey everyone! I'm trying to set up email sending in my Java app using Gmail's SMTP server. For some reason, it's getting stuck when I try to send an email. Can anyone help me figure out what's going on?

Here's a simplified version of my code:

```java
public void emailSender() {
    String sender = "[email protected]";
    String recipient = "[email protected]";
    String emailSubject = "Hello";
    String emailBody = "This is a test email";

    EmailDispatcher dispatcher = new EmailDispatcher(sender, recipient, emailSubject, emailBody);
    dispatcher.dispatch();
}

class EmailDispatcher {
    // ... constructor and fields ...

    public void dispatch() {
        Properties config = new Properties();
        config.put("mail.smtp.host", "smtp.gmail.com");
        config.put("mail.smtp.auth", "true");
        config.put("mail.smtp.port", "587");
        config.put("mail.smtp.starttls.enable", "true");

        Session mailSession = Session.getDefaultInstance(config, new Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(sender, "myPassword123");
            }
        });

        try {
            MimeMessage email = new MimeMessage(mailSession);
            // ... set email details ...
            Transport.send(email);
            System.out.println("Email sent successfully");
        } catch (MessagingException e) {
            throw new RuntimeException(e);
        }
    }
}

I’ve double-checked my Gmail settings and made sure to use app passwords. Any ideas what could be causing the hang-up? Thanks for your help!

2

hey mate, have u tried using SSL instead of TLS? sometimes that does the trick. change ur port to 465 and add this line:

config.put(“mail.smtp.socketFactory.class”, “javax.net.ssl.SSLSocketFactory”);

if that doesn’t work, maybe try a diff email provider like outlook. good luck!

3

I encountered a similar issue when implementing email functionality with Gmail SMTP. The problem might be related to Google’s security measures. Have you enabled ‘Less secure app access’ in your Google Account settings? If not, try that first.

Another potential cause could be network restrictions. Ensure your firewall isn’t blocking the SMTP connection. Also, double-check that you’re using the correct port (587 for TLS or 465 for SSL).

If those don’t work, consider using OAuth 2.0 for authentication instead of username/password. It’s more secure and less likely to be blocked by Gmail.

Lastly, add some debug logging to pinpoint where exactly it’s hanging. This can provide valuable insights into what’s going wrong during the SMTP handshake.

4

I’ve been down this road before, and it can be frustrating. One thing that’s not immediately obvious from your code is whether you’re using the latest JavaMail API. I had issues with older versions and Gmail’s SMTP.

Have you tried using Gmail’s OAuth 2.0? It’s a bit more complex to set up, but it’s way more reliable in my experience. You’ll need to create a Google Cloud project and set up credentials, but once that’s done, it’s smooth sailing.

Also, check your Gmail account settings. Sometimes, Google flags these connection attempts as suspicious. You might need to allow access for less secure apps or generate an app-specific password.

If you’re still stuck, try using a different email service temporarily, like SendGrid or Amazon SES. This can help isolate whether the issue is with your code or Gmail’s end.