title: Send mail in javax.mail without authentication
body: <p>I am using javax.mail to send mails in Java.
  Now that a part of the concept of my project changed I have to send a mail without authentication. I will have to change my createSession() method:</p>
  
  <pre><code>private void createSession() {
      properties.put("mail.smtp.auth", "true");
      properties.put("mail.smtp.starttls.enable", "true");
      properties.put("mail.smtp.host", server);
      properties.put("mail.smtp.port", port);
  
      session = Session.getInstance(properties, new javax.mail.Authenticator() {
          protected PasswordAuthentication getPasswordAuthentication() {
              return new PasswordAuthentication(username, password);
          }
      });
  }
  </code></pre>
  
  <p>It is rather obvious that I should change <code>mail.smtp.auth</code> to <code>false</code>, but what else should I change?</p>