It looks like you are passing to the Iteratormethod that is expecting Iterable.
Iterator :
Iterator over set
Iterable :
Implementing this interface allows an object to be an object of a foreach statement.
Iteratoris an object that can be used to iterate over a (different) collection. Iterableis an object that can be repeated.
, collection, - Iterables.filter(collection.iterator(), predicate). Iterables , Iterable, :
Iterables.filter(collection, predicate)