javamail

J2EE applications often need to send email notifications (order confirmations, password resets, alerts). Without a standard API, developers must deal with vendor-specific email protocols (SMTP, POP3, IMAP) directly.

JavaMail enables sending email messages in a platform-independent, protocol-independent manner from Java programs. It depends on JavaBeans Activation Framework (JAF), which also becomes part of J2EE.

1. Protocol-independent: Works with SMTP, POP3, IMAP without code changes
2. Session creation: Obtain javax.mail.Session (often via JNDI)
3. Message construction: Create MimeMessage with subject, body, recipients
4. Transport: Use Transport.send() to send the message
5. J2EE integration: Use in servlets, JSP, or EJB components

Example: Send order confirmation email from an e-commerce site.

• Platform-independent: Works on any Java platform
• Protocol-independent: Supports SMTP, POP3, IMAP
• JAF dependency: Requires JavaBeans Activation Framework
• J2EE standard: Part of J2EE platform
• Server-side use: Commonly used in J2EE deployments

• Built from: Java Platforms — JavaMail is part of J2EE
• Related: EJB Container — EJB components can use JavaMail
• Related: Servlets — servlets commonly send emails
• Related: JSP — JSP pages can trigger email sending

• JAF required: Forgetting JAF causes ClassNotFound errors
• SMTP configuration: Must configure SMTP host correctly
• Authentication: SMTP may require username/password
• Not covered: The source book does not cover JavaMail in detail