Create an int[] from an ArrayList<Integer>

Question

Is there an easy way of creating an int[] or the equivalent Integer[] from an ArrayList<Integer> ?

When I try (Integer[])list.getArray() , I get this stack trace:

Exception in thread "main" java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to [Ljava.lang.Integer;

The only other way I can think of is:

int[] array = new int[list.size()];
for (int i = 0; i < array.size; i++){
    array[i] = list.get(i);
    //or I could do list.remove(0), is there any difference?
}
return array;

but that way seems terribly slow.

Answer 1

yourIntList.toArray(new Integer[yourIntList.size()]);