Send email via gmail smtp in Javamail

@Test
public void testGMail() throws Exception {
        Properties props = System.getProperties();
       
        String[] tos = {"XXX,YYY,ZZZ"};
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.starttls.enable", "true");
        props.put("mail.smtp.host", "smtp.gmail.com");
        props.put("mail.smtp.port", "587");
        user = "Gmail email address";
        pass = "XXXX";
       
        Session session = Session.getInstance(props,
                  new javax.mail.Authenticator() {
                    protected PasswordAuthentication getPasswordAuthentication() {
                        return new PasswordAuthentication(user, pass);
                    }
                  });
          
        javax.mail.internet.MimeMessage message = new javax.mail.internet.MimeMessage(session); 
        message.setFrom(new javax.mail.internet.InternetAddress(from)); 
        for(String to : tos) {
            message.addRecipient(Message.RecipientType.TO, new javax.mail.internet.InternetAddress(to)); 
        } 
        message.setSubject("Test gmail");
        message.setContent("Test gmail content", "text/html");
      
        Transport.send(message);
        System.out.println("Done.");
}