code: public boolean containsAll(Collection<?> c) {
          int n = c.size();
          final Iterator<?> i = c.iterator();
          while (n-- != 0)
              if (!contains(i.next())) return false;
          return true;
      }
docs: Checks whether this collection contains all elements from the given collection.
  
  @param c a collection.
  @return <code>true</code> if this collection contains all elements of the argument.