convert arraylist to int array code example

Example 1: integer arraylist to int array

//only works in java 8 or later
list.stream().mapToInt(i -> i).toArray();

Example 2: convert int array to integer list java

int[] arr = {1,2,3};
IntStream.of(arr).boxed().collect(Collectors.toList());

Example 3: convert array of int to arraylist java

int[] ints = {1, 2, 3};
List<Integer> intList = new ArrayList<Integer>(ints.length);
for (int i : ints)
{
    intList.add(i);
}