public boolean equals(Object o) {

      if (this == o)

          return true;

      synchronized (this) {return list.equals(o);}

  }

  public int hashCode() {

      synchronized (this) {return list.hashCode();}

  }

  public A get(int index) {

      synchronized (this) {return list.get(index);}

  }

  public A set(int index, A element) {

    synchronized (this) { beforeChange(); A a = list.set(index, element); change(); ret a; }

  }

  public void add(int index, A element) {

    synchronized (this) { beforeChange(); list.add(index, element);} change();

  }

  public A remove(int index) {

    A e;

    synchronized (this) { beforeChange(); e = list.remove(index); }

    change();

    ret e;

  }

  public int indexOf(Object o) {

      synchronized (this) {return list.indexOf(o);}

  }

  public int lastIndexOf(Object o) {

      synchronized (this) {return list.lastIndexOf(o);}

  }

  public boolean addAll(int index, Collection<? extends A> c) {

    synchronized (this) { beforeChange(); if (!list.addAll(index, c)) false;} change(); true;

  }

  public ListIterator<A> listIterator() {

      return list.listIterator(); // doesn't implement all methods

  }

  public ListIterator<A> listIterator(int index) {

      return list.listIterator(index); // doesn't implement all methods

  }

  /*public void replaceAll(UnaryOperator<A> operator) {

      synchronized (this) {list.replaceAll(operator);}

  }*/

  public void sort(Comparator<? super A> c) {

    synchronized (this) { beforeChange(); list.sort(c);} change();

  }