How do I send email using Gmail via TLS?

The following example show you how to send email using Gmail SMTP via TLS connection. The username and password is use to authenticate you against the Gmail.

The configuration / properties used for connection to the Gmail SMTP is defined in the createConfiguration() method. The properties include information such as the SMTP host address, port number, etc.

To send email using Gmail via SSL see the following code snippet How do I send email using Gmail via SSL?.

Let’s see the code snippet below:

package org.kodejava.example.mail;

import javax.mail.*;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import java.util.Date;
import java.util.Properties;

public class GmailSendEmailTLS {
    private static final String USERNAME = "kodejava";
    private static final String PASSWORD = "********";

    public static void main(String[] args) throws Exception {
        // Email information such as from, to, subject and contents.
        String mailFrom = "";
        String mailTo = "";
        String mailSubject = "TLS - Gmail Send Email Demo";
        String mailText = "TLS - Gmail Send Email Demo";

        GmailSendEmailTLS gmail = new GmailSendEmailTLS();
        gmail.sendMail(mailFrom, mailTo, mailSubject, mailText);

    private void sendMail(String mailFrom, String mailTo, String mailSubject,
                          String mailText) throws Exception {

        Properties config = createConfiguration();

        // Creates a mail session. We need to supply username and
        // password for Gmail authentication.
        Session session = Session.getInstance(config, new Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(

        // Creates email message
        Message message = new MimeMessage(session);
        message.setSentDate(new Date());
        message.setFrom(new InternetAddress(mailFrom));
            new InternetAddress(mailTo));

        // Send a message
        Transport.send(message, GmailSendEmailTLS.USERNAME, GmailSendEmailTLS.PASSWORD);

    private Properties createConfiguration() {
        return new Properties() {{
            put("mail.smtp.auth", "true");
            put("", "");
            put("mail.smtp.port", "587");
            put("mail.smtp.starttls.enable", "true");

Maven Dependencies

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  1. Thanks a lot.

    Please help me. In runtime I receive this error message:

    Caused by: PKIX path building failed: unable to find valid certification path to requested target
            ... 18 more
    Caused by: unable to find valid certification path to requested target

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