To send an email message, an app prepares a MimeMessage object, then sends it with the static method send() on the Transport class. The message is created using a JavaMail Session object. The Session and the Transport work with the App Engine Mail service without any additional configuration.

The Used Package:

import java.util.Properties;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;


The Body:

//....the class begining

  

Properties props = new Properties();
        Session session = Session.getDefaultInstance(props, null);

        String msgBody = "...";

        try {
            Message msg = new MimeMessage(session);
            msg.setFrom(new InternetAddress("[email protected]", "Example.com Admin"));
            msg.addRecipient(Message.RecipientType.TO,
                             new InternetAddress("[email protected]", "Mr. User"));
            msg.setSubject("Your Example.com account has been activated");
            msg.setText(msgBody);
            Transport.send(msg);

        } catch (AddressException e) {
            // ...
        } catch (MessagingException e) {
            // ...
        }

Calls to the Mail service are asynchronous, and return immediately. The Mail service manages the process of contacting the recipients' mail servers and delivering the message. If there is a problem sending the message to any recipient, or if a recipient's mail server returns a "bounce" message, the error message goes to the sender.