org.hibernate.type.SortedSetType inherits the implementation of instantiate(int anticipatedSize) from org.hibernate.type.SetType. In the effect, a java.util.HashSet gets instatiated instead of a java.util.TreeSet. Collections mapped with sort="natural" or sort="<T implements java.util.Comparator>" will never be sorted once they are retrieved from the database. Since is is neither possible nor makes it sense to create a TreeSet with an initial size, the missing implementation of instantiate(int anticipatedSize) may safely ignore the argument and delegate to instantiate().
Hibernate 3.2.0.cr3, affects all environments