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();
  }