Java ArrayList add item outside current size

Question

Wondering whether there is an efficient way to add an item to Java's ArrayList at a bigger position than its current size:

Scenario:

   ArrayList<Item> items = new ArrayList<Item>;
   ... let's say I add three elements

Now I would like to add an item at position 10 (leaving items from 3 to 10 to null)

  items.add(10,newItem);  // item.size() == 3 

Is there an efficient way resizing/filling an ArrayList with nulls?

Java's implementation makes size field private :-(..

Answer 1

imho the best thing you can do is items.addAll(Collections.nCopies(6, null)) and hope, that ArrayList implements some behaviour to internally fasten this up

Answer 2

How about this?

ArrayList<Item> items = new ArrayList<Item>();

items.add(new Item(0));
items.add(new Item(1));
items.add(new Item(2));

items.addAll(Collections.<Item>nCopies(7, null));
items.add(10,new Item(10));

System.out.println(items);

prints

[0, 1, 2, null, null, null, null, null, null, null, 10]