code: static boolean equalsImpl(Multiset<?> multiset, @NullableDecl Object object) {
      if (object == multiset) {
        return true;
      }
      if (object instanceof Multiset) {
        Multiset<?> that = (Multiset<?>) object;
        /*
         * We can't simply check whether the entry sets are equal, since that
         * approach fails when a TreeMultiset has a comparator that returns 0
         * when passed unequal elements.
         */
  
        if (multiset.size() != that.size() || multiset.entrySet().size() != that.entrySet().size()) {
          return false;
        }
        for (Entry<?> entry : that.entrySet()) {
          if (multiset.count(entry.getElement()) != entry.getCount()) {
            return false;
          }
        }
        return true;
      }
      return false;
    }
docs: An implementation of {@link Multiset#equals}.