public void readUpdate(InputStream in) throws Exception {
  ObjectInputStream s=new ObjectInputStream(in);
  applyUpdate(s.readObject());
}

public void readUpdate ( InputStream in ) throws Exception { ObjectInputStream s = new ObjectInputStream ( in ) ; applyUpdate ( s . readObject ( ) ) ; }
reads a stably logged update ( a serializable object ) from a stream . this callback is invoked during recovery , once for every record in the log . after reading the update , this method invokes the applyupdate ( abstract ) method in order to execute the update .
