JavaMail reading recent unread mails using IMAP

Question

I have a requirement to retrieve unread mails from Gmail. I am using Java Mail API. By default, this API retrieves mails from the oldest to newest. But I need to retrieve re

Answer 1

Make sure to use the IMAP protocol, as it supports for flagging.

Do following changes to your code:

1. replace inbox.open( Folder.READ_ONLY ); by inbox.open( Folder.READ_WRITE );

2. Then after reading the message, set the flag like so:

   message.setFlag(Flags.Flag.SEEN, true);
   

Full example:

    import javax.mail.*;
    import javax.mail.search.FlagTerm;
    import java.util.*;

    public class GmailFetch {

      public static void main( String[] args ) throws Exception {

        Session session = Session.getDefaultInstance(new Properties( ));
        Store store = session.getStore("imaps");
        store.connect("imap.googlemail.com", 993, "username@gmail.com", "password");
        Folder inbox = store.getFolder( "INBOX" );
        inbox.open( Folder.READ_WRITE );

        // Fetch unseen messages from inbox folder
        Message[] messages = inbox.search(
            new FlagTerm(new Flags(Flags.Flag.SEEN), false));

        // Sort messages from recent to oldest
        Arrays.sort( messages, ( m1, m2 ) -> {
          try {
            return m2.getSentDate().compareTo( m1.getSentDate() );
          } catch ( MessagingException e ) {
            throw new RuntimeException( e );
          }
        } );

        for ( Message message : messages ) {
          System.out.println( 
              "sendDate: " + message.getSentDate()
              + " subject:" + message.getSubject() );
              message.setFlag(Flags.Flag.SEEN, true);
        }
      }
    }