private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException {
  s.defaultWriteObject();
  for (Node<K,V> n=findFirst(); n != null; n=n.next) {
    V v=n.getValidValue();
    if (v != null) {
      s.writeObject(n.key);
      s.writeObject(v);
    }
  }
  s.writeObject(null);
}

private void writeObject ( java . io . ObjectOutputStream s ) throws java . io . IOException { s . defaultWriteObject ( ) ; for ( Node < K , V > n = findFirst ( ) ; n != null ; n = n . next ) { V v = n . getValidValue ( ) ; if ( v != null ) { s . writeObject ( n . key ) ; s . writeObject ( v ) ; } } s . writeObject ( null ) ; }
save the state of this map to a stream .
