How does the idle() for IMAP works in JavaMail API ?

Question

Hi,
I would like to know how the idle() works in the JavaMail API.
Please check the below code:
f.addMessageCountListener(new MessageCountAdapter(){
                @Override
          public void messagesAdded(MessageCountEvent ev) {
              Message[] msgs = ev.getMessages();
              System.out.println("Got " + msgs.length + " new messages for:" +  userID);             
                    try
                        newMailCount = newMailCount + msgs.length;
                        System.out.println("Got total:" + newMailCount + " new messages for:"+ userID);             
                    } catch (Exception e) {
                   e.printStackTrace();
for (;;) {
              if ( f instanceof IMAPFolder) {
                    IMAPFolder impf = (IMAPFolder)f;
                    impf.idle();
                    System.out.println("IDLE done");
              } When i run the above code, the idle command keeps on listening to the new mails arrive. When will the idle process stop?
O/P :
Got 1 new messages for:test1
Got total:1 new messages for:test1
Got 1 new messages for:test1
Got total:2 new messages for:test1
Got 1 new messages for:test1
Got total:3 new messages for:test1
Got 1 new messages for:test1
As you can see, the last line: "IDLE done" is not at all printed.
How can i stop the idle process ?
Thanks in advance,
grace.

Answer 1

For the above code, after some time the below exception is thrown:
javax.mail.FolderClosedException: * BYE JavaMail Exception: java.net.SocketException: Connection reset
at com.sun.mail.imap.IMAPFolder.throwClosedException(IMAPFolder.java:2464)
at com.sun.mail.imap.IMAPFolder.idle(IMAPFolder.java:2256)
Is this the normal behaviour ? Or is there anything else that i should take care of ?
Thanks & Regards,
grace