Pop3 message numbers

Question

Hi
I am writing an email client using javamail and POP3 server. But the problem is if I delete any mail then the messages are reordered but when a new mail arrives it is given a message number in the middle .
Can any one tell what exact algorithm is used for givimg the message number. Or any other way for tracking new messages.
Any Help will be welcome.

Answer 1

hi,
Try this....... It will show you the listing of ur messages......
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import java.util.*;
import java.io.*;
import javax.mail.*;
import javax.mail.internet.*;
import javax.activation.*;
import com.sun.mail.pop3.* ;
import com.sun.mail.imap.* ;
public class SunMsgShow
static String protocol =null ;
static String host = null ;
static String user = null;
static String password = null;
static String mbox = "INBOX";
static int port = -1;
     public static void main(String s[])
          protocol = "pop3" ;
          host = "pop.mail.yahoo.com" ;
          user = "shahnazali_99" ;
          password = "ur Password here";
     try
                         Properties props = System.getProperties();
                         Session session = Session.getDefaultInstance(props, null);
                         session.setDebug(false );
                         // Get a Store object
                         Store store = null;
                              if (protocol != null)
                                   store = session.getStore(protocol);
                              else
                                   store = session.getStore();
                              // Connect
                              if (host != null || user != null || password != null)
                                   store.connect(host, port, user, password);
                              else
                                   store.connect();
                         // Open the Folder
                         Folder folder = store.getDefaultFolder();
                         if (folder == null)
                              System.exit(0) ;
                         folder = folder.getFolder(mbox);
                         if (folder == null)
                              System.exit(0) ;
                         try
                              folder.open(Folder.READ_WRITE);
                         catch (MessagingException ex)
                              folder.open(Folder.READ_ONLY);
                              // Attributes & Flags for all messages ..
                              Message[] msgs = folder.getMessages();
                              // Use a suitable FetchProfile
                              FetchProfile fp = new FetchProfile();
                              fp.add(FetchProfile.Item.ENVELOPE);
                              folder.fetch(msgs, fp);
                              for (int i = 0; i < msgs.length; i++)
                                   dumpMessageHeader(msgs);
                                   if (folder instanceof com.sun.mail.pop3.POP3Folder)
                                        com.sun.mail.pop3.POP3Folder pf = (com.sun.mail.pop3.POP3Folder)folder;
                                   String uid = pf.getUID(msgs[i]);
                                   if (uid != null)
                                             System.out.println ( "UID:" + uid );
                                   else
                                        if (folder instanceof com.sun.mail.imap.IMAPFolder)
                                             com.sun.mail.imap.IMAPFolder pf = (com.sun.mail.imap.IMAPFolder)folder;
                                             long uid = pf.getUID(msgs[i]);
                                             System.out.println ( "UID:" + uid );
                         folder.close(false);
                         store.close();
          catch (AuthenticationFailedException ex)
          catch (MessagingException ex)
public static void dumpMessageHeader(Message m) throws MessagingException
               Address[] a;
               String from = "";
               String subject ="";
          // FROM
               if ((a = m.getFrom()) != null)
               for (int j = 0; j < a.length; j++)
                         from = from + " " + a[j];
          // SUBJECT
               subject = m.getSubject() ;
               String aboutMessage = "From " + from + " Subject: " + subject ;
               System.out.println ( aboutMessage);
=================================
Bye,
Shaan