Maybe something like this in resourceHash.hpp:

  template<class ITER>
  void iterate(ITER* iter) const { // the old API
    auto f = [&] (K& k, V& v) {
      return iter->do_entry(k, v);
    };
    iterate(f);
  }

  template<typename F>
  void iterate(F f) const { // lambda enabled API
    Node* const* bucket = table();
    const unsigned sz = table_size();
    while (bucket < bucket_at(sz)) {
      Node* node = *bucket;
      while (node != NULL) {
        bool cont = f(node->_key, node->_value);
        if (!cont) { return; }
        node = node->_next;
      }
      ++bucket;
    }
  }

==================
Example usage in heapShared.cpp

    int n = 0;
    auto f = [&] (oop& k, oop& v) {
      n++;
      return true;
    };
    archived_object_cache()->iterate(f);
    tty->print_cr("Counted = %d objects", n);
==================
Need to verify that there's no performance degradation in the code generated by modern C++ compilers (when either old or new API is used).