A system for filtering messages from your IMAP inbox on-demand. Filters are defined in an XML file. Matching messages can be moved, copied, or deleted. This is all independant of your choice of email client, as long as you use IMAP.
gavamail is a POP3/IMAP server implemented in JAVA for reading your gmail e-mail with your favorite mail client. Currently only POP3 is implemented but I hope to implement IMAP too. Libraries provided by the g4j and libgmail projects are used.