ArrayList -> 배열

array -> ArrayList

new ArrayList<>(Arrays.asList(array));

String[] array = new String[3];
ArrayList<String> arrayList = new ArrayList<>(Arrays.asList(array));

List<Integer> intList = Arrays.stream(arr)
						.boxed()
                        .collect(Collectors.toList());

ArrayList -> array

ArrayList<String> arrayList = new ArrayList<>();
String[] array = arrayList.toArray(new String[arrayList.size()]);