10-04-2017, 08:50 PM
i think which is Java Email Server (JES) similar a project was done by erichttp://ericdaughertyjava/mailserver/changes.html see
and others like Coadunation,Jsmtpd
also similar project
see http://coadunationcontent/faq faq of Coadunation a java based server
i suggest you to start to learn from already implimented project,,