code: @Override
    public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
      super.readExternal(in);
      this.splitHistory = SplitHistory.readExternal(in);
    }
docs: Calls the super method and reads the MBR object 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.