code: @Override
    public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
      super.readExternal(in);
      int k_max = in.readInt();
      knnDistances = new double[k_max];
      for(int i = 0; i < k_max; i++) {
        knnDistances[i] = in.readDouble();
      }
    }
docs: Calls the super method and reads the parameter k_max and knn distance of
  this entry from the specified input stream.
  
  @param in the stream to read data from in order to restore the object
  @throws java.io.IOException if I/O errors occur
  @throws ClassNotFoundException If the class for an object being restored
  cannot be found.