java mail

I need to send an email from ejb. At the same time, I want to submit to mail queue, in case if my mail server is down!! That queue should look for my mail server availability and should send out emails. How do i do that?

The JavaMail API is designed to use liteners to check connection events. So you can test whether or not a message made it to the SMTP server easily enough (read the docs to see exaclty how).

I'm not strictly sure what you mean by "mail queue", but its easy enough to persist unsent messages somewhere to be handled by another process. Just write them to a DB table or the file system or whatever, and write some occasional process to read any and try to resend.