Just commited my new Java IMAP client library to MiniG svn. My lib is based on apache mina and looks like ristrerro imap api, with speed added. Pretty happy with the results.

Ristretto was fine, but switching to a mina based implementation cut the time for fetching an email from 170ms to 8ms :-) My new API still use a lot of Ristretto for header decoding & mime parsing, they did a great job.