A ClassMetaDataFlagMismatchException is thrown if the flag of a
persistent field of an enhanced class does not match what would be
expected based on the corresponding JDO metadata.
A ClassMetaDataMismatchException is thrown if the names, types, or
flags of the persistent fields of an enhanced class do not match those that
would be expected based on the corresponding JDO metadata.
A DuplicateFieldException is thrown if more than one definition for
the same field name is encountered in the XML metadata for a given
persistence capable class.