Using the following provider on 0.6.1, I'm faced with a ClassCastException. It might also be worth noting that I face the same exception when attempting to us the KerberosProvider option.
*Provider:* <provider> <identifier>ldap-provider</identifier> <class>org.apache.nifi.ldap.LdapProvider</class> <property name="Authentication Strategy">SIMPLE</property> <property name="Manager DN">dethklok\toki</property> <property name="Manager Password">bananasticker</property> <property name="TLS - Keystore"></property> <property name="TLS - Keystore Password"></property> <property name="TLS - Keystore Type"></property> <property name="TLS - Truststore"></property> <property name="TLS - Truststore Password"></property> <property name="TLS - Truststore Type"></property> <property name="TLS - Client Auth"></property> <property name="TLS - Protocol"></property> <property name="TLS - Shutdown Gracefully"></property> <property name="Referral Strategy">FOLLOW</property> <property name="Connect Timeout">10 secs</property> <property name="Read Timeout">10 secs</property> <property name="Url">ldap://ldap.metalocalypse.com</property> <property name="User Search Base">CN=Users,DC=metalocalypse,DC=local</property> <property name="User Search Filter">foo</property> <property name="Authentication Expiration">12 hours</property> </provider> *Exception:* Caused by: java.lang.ClassCastException: class org.apache.nifi.ldap.LdapProvider at java.lang.Class.asSubclass(Class.java:3208) ~[na:1.7.0_79] at org.apache.nifi.authorization.AuthorityProviderFactoryBean.createAuthorityProvider(AuthorityProviderFactoryBean.java:173) ~[na:na] at org.apache.nifi.authorization.AuthorityProviderFactoryBean.getObject(AuthorityProviderFactoryBean.java:111) ~[na:na] at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean(FactoryBeanRegistrySupport.java:168) ~[na:na] ... 75 common frames omitted