Question: Explain the structure of Javamail API

Answer: The JavaMail API has classes such as Message, Store and Transport. The API can be used to subclass for providing new protocols and some additional functionality when needed. The concrete subclasses of this API are MimeMessage and MimeBodyPart which are implemented widely by the internet mail protocols. The supporting protocols for Javamail API are IMAP4, POP3 and SMTP.

The Java mail architectural components include the following:

Abstract Layer: This layer declares the classes, interfaces and abstract methods that are intended for supporting the mail functions which all mailing systems supports.

Intranet Implementation Layer: The implementation of MIME internet standards and part of the abstract layer comprises this layer.

Java Bean Activation Framework: The encapsulation of message data and handling the data interacting commands is used by the Javabean Activation Framework.