Under what circumstances does IMAPFolder.getType return -1 ? I can't tell from the javadoc, it doesn't mention that -1 is an option, but I am seeing it happen. I'm not sure what to look for in the network interaction because I am not sure how the folder type is calculated in the list command.
A30 LIST "" INBOX
* LIST (\Unmarked \HasNoChildren) "/" "INBOX"
A30 OK LIST completed
I don't see any trace output from JavaMail for this function.