Hello Tung! Thanks for asking!
The Mime Message-Id header is defined in RFC-822. You can more or less relate it with the content of a message. The EmailId is defined in RFC-8621. It identifies a unique email in somebody mailbox. Now consider: Bob sends a Message to Alice. That Message (as per RFC-822) will correspond to two emails with the same content (one in Bob Sent mailbox, one in Alice INBOX), so with the same Message-Id header, but two distinct emailId. Also the usages are different. Message-Id is useful to relates messages to each other (A is a reply to B, a forward) and can be used to form email threads. In your context (Message Delivery Notification) it allows to know for which message a given MDN is issued. EmailId designate a single email in somebody mailbox, and I can use it to delete the email, update its flags, move it to another mailbox. https://jmap.io/spec-mail.html#emails > id: Id (immutable; server-set) The id of the Email object. Note > that this is the JMAP object id, NOT the Message-ID header field > value of the message [@!RFC5322]. The message-id field needs to be specified while generating emails. I am unsure here but javax.mail / mime4j should set one if none is specified. Last but not least: this is a rather technical discussion, more related to James development, but maybe not relevant for James users. As such I believe next time we want to discuss technical details related to James development (which is great!) we should do it on server-dev. Cheers, Benoit Le 14/04/2021 à 15:12, Tung Tran Van a écrit : > Hello all, > > I am an amateur. I am confused about the difference between Message-ID *(a > field at header in MimeMessage)* and EmailId*(or MessageId, both have the > same name)*. > > I usually use emailId to retrieve messages > *(MessageIdManager.java.getMessage)*, but when I check related MimeMessage > results, I detect that the Message-ID Header has other value. > > So, What is the purpose of the Message-ID Header? How is it created? > > May somebody help me understand it? > > *Thank you,* > > *Tung, Tran Van* > --------------------------------------------------------------------- To unsubscribe, e-mail: server-user-unsubscr...@james.apache.org For additional commands, e-mail: server-user-h...@james.apache.org