Java and Electronic Mail - Java - page 682

Chapter 17. Java and Electronic Mail
Introduction
Sending and receiving email from a program is easy with Java. If you are writing an applet,
you can simply get the browser to compose and send it for you. Otherwise, you can use the
JavaMail Extension (package javax.mail ) to both send and read mail. JavaMail provides
three general categories of classes: Message s, Transport s, and Store s. A Message , of
course, represents one email message. A Transport is a way of sending a Message from
your application into the network or Internet. A Store represents stored email messages and
can be used to retrieve them as Message objects. Thus, a Transport is for sending email and
a Store is for reading it. One other class, Session , is used to obtain references to the appro-
priate Store and/or Transport objects that you need to use.
The JavaMail package is included in JavaEE and can be downloaded for JavaSE use. It's
worth it: for the cost of a few minutes' downloading time, you get the ability to send and re-
ceive electronic mail over a variety of network protocols. The JavaMail project is hosted on
java.net . You can download a JAR file containing all the standard protocol providers
(SMTP, IMAP, POP3), or an API JAR just to compile against, or download the basic API
and download the protocols individually. There are Maven artifacts in [ Maven Central as
well. There is a JavaMail home page at Oracle. Finally, there is at least one alternative imple-
mentation, GNU JavaMail.
As you might have guessed from Chapter 13 , it's also not that big a stretch to write code
yourself that contacts an SMTP server and pretends to be a mail program. Hey, why pretend?
You really have a mail program at that point! This is not shown in the topic, but is available
in the javasrc repo under src/main/java/email/SmtpTalk.java , for use as an aid to understand-
ing the SMTP protocol.