@Override public void reloadACK(final PagePosition position){
  if (recoveredACK == null) {
    recoveredACK=new LinkedList<>();
  }
  recoveredACK.add(position);
}

@ Override public void reloadACK ( final PagePosition position ) { if ( recoveredACK == null ) { recoveredACK = new LinkedList < > ( ) ; } recoveredACK . add ( position ) ; }
theres no need to synchronize this method as it ' s only called from journal load on startup
