This is all well and good, while setting up the database, I realized that this doesn't quite meet my needs.
At least, it doesn't seem to; they're only using the database for a small part of the functionality.
What I'm looking for is to persist e-mails, in the form of
javax.mail.Message's, to a database. It seems that, to my understanding, dbmail, which fits the requirements, won't work and I'm having trouble with James.
Postfix seems fine, provided that
postfix-mysql can be made to work more like what dbmail does. However, that's looking less and less likely.