JDK1.8以下的處理方式

List<String> list = new ArrayList<String>(Arrays.asList("are","you","ok","?"));

String[] array = new String[list.size];

list.toArray(array);

String[] array = {"are","you","ok","?"};

List<String> list = new ArrayList<String
 
>(Arrays.asList(array));

JDK1.8的處理方式

List<Integer> list = new ArrayList<Integer
 
>(Arrays.asList(1,2,3,4,5,6));

int[] array = list.stream().mapToInt(x->x).toArray();

int[] array = {1,2,3,4,5,6};

List<Integer> list = Array.stream(array).boxed().collect(Collectors.toList());