code: public void readObject (ObjectInputStream in)
          throws IOException, ClassNotFoundException
      {
          int ecount = in.readInt();
          for (int ii = 0; ii < ecount; ii++) {
              @SuppressWarnings("unchecked") K key = (K)in.readObject();
              @SuppressWarnings("unchecked") V value = (V)in.readObject();
              put(key, value);
          }
      }
docs: Reads our custom streamable fields.