Prereq is OpenDJ installed in /opt/opendj

$ sudo su - opendj
$ /opt/opendj/setup \
--cli \
--no-prompt \
--doNotStart \
--baseDN "dc=example,dc=com" \
--addBaseEntry \
--ldapPort 1389 \
--adminConnectorPort 4444 \
--enableStartTLS \
--ldapsPort 1636 \
--generateSelfSignedCertificate \
--acceptLicense \
--rootUserDN "cn=Directory Manager" \
--rootUserPassword [password] \
--hostname [hostname]

Start OpenDJ at boot

$ sudo /opt/opendj/bin/create-rc-script \
 --outputFile /etc/init.d/opendj \
 --userName opendj
$ sudo update-rc.d opendj defaults