To communicate with LDAP from a Tomcat security Realm, everything you need is already pre-supplied with Tomcat. All that's required is to set the Realm configuration properties properly.
The secret of how to be miserable is to constantly expect things are going to happen the way that they are "supposed" to happen.
You can have faith, which carries the understanding that you may be disappointed. Then there's being a willfully-blind idiot, which virtually guarantees it.
Remember to always leap before you look. But always take the time to smell the tiny ads:
a bit of art, as a gift, the permaculture playing cards