This property caches user DNs (distinguished names) locally when
derby.authentication.provider
is set to LDAP and
derby.authentication.ldap.searchFilter
is set to derby.user. When you provide a user DN with this property,
is able to avoid an
LDAP search for that user's DN before authenticating. For those users without
DNs defined with this property,
performs a search using
the default value of derby.authentication.ldap.searchFilter.