The idea is to build an email archive system for lazy people ... like me ;-). At first you can move messages by date in a dedicated mailbox on-line. Or archive messages in compressed format to be stored somewhere. The compressed archive is indexed to be searchable and recoverable if needed. This project is in early stages of development (near 1.0 in the road map).
jIMAP provides an java based implementation of the IMAP protocol. It provides direct access to all featurs of the IMAP protocol. It could be used to build a full blown mail program