Oracle treats empty strings and nulls as equals - if an empty string is inserted, later, it returns as NULL.
This cause problems when a service def is created, with implementation classname specified as a zero length string. However, when later it is retrieved or updated or delete, Ranger throws various exceptions. In 1.0.0 a couple of exceptions are fixed, because of
RANGER-1377, however in 0.7, there is more NPE.