Java Email Session create with Authenticator

import java.util.Properties;

import javax.mail.Authenticator;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

public class Main {

   public static void main(String[] args) {
      Properties properties = new Properties();
      properties.put("mail.smtp.host", "smtp.somewhere.com");
      properties.put("mail.smtp.auth", "true");

      Session session = Session.getDefaultInstance(properties, new MessageAuthenticator("username", "password"));

      Message message = new MimeMessage(session);
      try {/*w  w w  .  j ava  2  s  . c o m*/
         message.setFrom(new InternetAddress("someone@somewhere.com"));
         message.setRecipient(Message.RecipientType.TO, new InternetAddress("someone@somewhere.com"));
         message.setSubject("Subject");
         message.setContent("This is a test message", "text/plain");
         Transport.send(message);
      } catch (MessagingException e) {
         e.printStackTrace();
      }
   }

}

class MessageAuthenticator extends Authenticator {
   PasswordAuthentication authentication = null;

   public MessageAuthenticator(String username, String password) {
      authentication = new PasswordAuthentication(username, password);
   }

   @Override
   protected PasswordAuthentication getPasswordAuthentication() {
      return authentication;
   }
}