How can I convert List<Integer> to int[] in Java?

You can use the toArray() method of the List interface to convert a List<Integer> to an int[] in Java. Here's an example:

List<Integer> list = Arrays.asList(1, 2, 3, 4, 5);
int[] array = list.stream().mapToInt(i -> i).toArray();

Alternatively, you can use the List.toArray(T[] a) method, which returns an array containing all of the elements in the list in proper sequence (from first to last element). Here's an example:

List<Integer> list = Arrays.asList(1, 2, 3, 4, 5);
int[] array = new int[list.size()];
array = list.toArray(array);

I hope this helps! Let me know if you have any other questions.