The Java Email Server (JES) plug-in is an embedded instance launcher of JES (email server) under Eclipse; it's intended to help developers viewing the layout of mails sent by their application to the clients (subscription mails, etc...) in local.
DevWare is an Developer Groupware,with Calender, E-Mail, Chat, Todo's, integrated CVS / SVN, own Version Control, Documentation System, Redactionell System. It's written in Java, the Server runs on Jboss, Rich Client is Eclipse.