A JavaMail developer specializes in using the JavaMail API to build and maintain applications that need to send, receive, and process emails. Their duties include designing email systems, troubleshooting any issues related to email communication, and ensuring the system's security. They also handle tasks such as message organization and storage, and email server connection. They often need to work with MIME (Multipurpose Internet Mail Extensions) messages, and may also integrate the JavaMail functionality into larger software systems. They need to be proficient in Java and understand Internet protocols like SMTP, , and IMAP.