I wanted to try the mail feature in J but I only had access to imap servers that required both SSL and TLS to connect. So instead of using a different imap server, I ended up adding support for SSL and TLS mailbox URLs in J. ;) I've tested sending and receiving emails with my gmail account but I haven't tried much more than that.
I don't have intentions of working on J's email client to bring it up to something that would replace your current email client. For example, POP3 doesn't support SSL or TLS yet and the SMTP session doesn't remember your password so you need to type it in each time you send an email.
To enable SSL and TLS for your imap account, add the '/ssl' and '/tls' flags to your mailbox URL. For example,