Javadoc
Indicates whether definition is should be used as default account type.
If true value is returned then the definition should be used as a default
account type definition. This is a way how a resource connector may
suggest applicable object classes (resource object definitions) for
accounts.
If no information about account type is present, false should be
returned. This method must return true only if isAccountType() returns
true.
The exception should be never thrown unless there is some bug in the
code. The validation of at-most-one value should be done at the time of
schema parsing. The exception may not even be thrown at all if the
implementation is not able to determine duplicity.