The funny thing is:
Using JDK 1.2.2 and JavaMail API 1.2/1.3, for a folder MessageAdded does not get called "if a new message is created and appended to the folder ( not sent of copied using copymessage)".

If the same JDK 1.2.2 and JavaMail API 1.2 and 'j2ee.jar' is added to the class path as the first item, the MessageAdded works for the above case.
It took us a few days to figure out this. I still don't know the reason why it behaves so.

In both the cases if a message gets removed, MessageRemoved gets called. But the getMessageCount() seems to return a incorrect message count, not taking into account the removed message.

This issue has also been forwarded to Javasoft.

Try sending this message to the JavaMail mailing list. If this is a design issue, the JavaMail architect will answer. Also, be sure to state which version of JavaMail you are using.