Apache commons mail not sending through gmail

Apache Commons Mail is a popular library for sending emails in Java, but it can be challenging to configure it to send emails through Gmail. Here are some common issues and solutions to help you troubleshoot:

Issue 1: Authentication failure

Check that your Gmail account is set up to allow less secure apps to access your account. You can do this by going to your Google Account settings > Security > Less secure app access.
Make sure you're using the correct username and password for your Gmail account.
If you're using 2-Step Verification, you'll need to generate an App Password and use that instead of your regular password.

Issue 2: SMTP connection failure

Verify that your Gmail account is set up to allow SMTP connections. You can do this by going to your Google Account settings > Forwarding and POP/IMAP > Enable IMAP.
Check that your SMTP server is set up correctly. The default SMTP server for Gmail is smtp.gmail.com on port 587.
Make sure you're using the correct SMTP authentication settings. For Gmail, you'll need to use PLAIN or XOAUTH2 authentication.

Issue 3: Email not being sent

Check that your email message is being constructed correctly. Make sure you're setting the from address, to address, and subject correctly.
Verify that your email message is not being blocked by Gmail's spam filters. You can try sending a test email to yourself to see if it's being delivered.

Apache Commons Mail configuration

Here's an example of how you can configure Apache Commons Mail to send emails through Gmail:

import org.apache.commons.mail.Email;
import org.apache.commons.mail.EmailException;
import org.apache.commons.mail.SimpleEmail;

public class GmailSender {
    public static void main(String[] args) {
        Email email = new SimpleEmail();
        email.setHostName("smtp.gmail.com");
        email.setSmtpPort(587);
        email.setAuthenticator(new DefaultAuthenticator("[email protected]", "your-password"));
        email.setFrom("[email protected]");
        email.setSubject("Test email");
        email.setMsg("This is a test email");
        try {
            email.send();
        } catch (EmailException e) {
            e.printStackTrace();
        }
    }
}

Additional tips

Make sure you're using the correct JavaMail API version. Apache Commons Mail uses JavaMail API under the hood, so you'll need to ensure you're using a compatible version.
If you're still having issues, try enabling debug logging for Apache Commons Mail to see if it provides any additional error messages.
Consider using a more advanced email library like JavaMail API or Spring's JavaMailSender to simplify your email sending code.

I hope these tips help you troubleshoot and resolve the issue with Apache Commons Mail not sending emails through Gmail!

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Apache commons mail not sending through gmail