Java

Get the POP3 UIDL of an Email

Demonstrates the read-only Chilkat Email.Uidl property, which contains the unique message identifier assigned by a POP3 server; the value is also represented by the X-UIDL header field. This example sets X-UIDL directly to illustrate how it maps to the Uidl property (normally the value comes from the POP3 server during download).

Background: A UIDL ("unique ID listing") is POP3's stable identifier for a message in a mailbox — it stays the same across sessions, so a client can remember which messages it has already downloaded and avoid fetching them again. Note this is POP3-specific: IMAP uses its own UID instead, which Chilkat stores in the ckx-imap-uid header rather than in Uidl.

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import com.chilkatsoft.chilkat2.Email;

public class ChilkatExample {

    public static void main(String[] args) {
        // Demonstrates the read-only Email.Uidl property, which contains the unique message
        // identifier assigned by a POP3 server.  The value is represented by the X-UIDL header
        // field.  Here we set X-UIDL directly to show how it maps to the Uidl property.

        Email email = new Email();

        // Normally the POP3 server assigns this; we set it here for demonstration.
        email.addHeaderField("X-UIDL", "0000000123abcdef");

        System.out.println("Uidl = " + email.getUidl());
    }
}