Adds all of the elements in the specified collection to this set.
@param c collection containing elements to be added to this set
@return {@code true} if this set changed as a result of the call
@throws ClassCastException if the elements provided cannot be compared
with the elements currently in the set
@throws NullPointerException if the specified collection is null or
if any element is null and this set uses natural ordering, or
its comparator does not permit null elements
Adds all of the elements in the specified collection to this set.
@param c collection containing elements to be added to this set @return {@code true} if this set changed as a result of the call @throws ClassCastException if the elements provided cannot be compared with the elements currently in the set @throws NullPointerException if the specified collection is null or if any element is null and this set uses natural ordering, or its comparator does not permit null elements