I'm not aware of any package in J2SE that can retreive/update or insert elements in LDAP. Still there are some open source packages that you can use. For example :
Where 1 is maybe the most interesting reference. It is not a standard LDAP API, but is actually a JDBC-LDAP bridge driver. So when you are not really used to programming for an LDAP server, you can use your JDBC knowledge to do the same.