can i get imap access using just postfix and mailx?

I have postfix and mailx installed on a CentOS 7 server. I am able to send and receive email from the command line using the mailx command. I am also able to read email in each user's inbox using nano /var/spool/mail/username.

My impression is that mailx and postfix only support smtp. The problem is that I am trying to use another API (JavaMail) to read a user's inbox, and all the examples use imap or pop3 protocols. Is there a way that I can get postfix/mailx to be accessible via imap? Or do I have to also install dovecot before I can use imap to retrieve inbox contents?