[java] ArrayList to Array , ArrayList to Array

ArrayList to Array

List<Integer> list = new ArrayList<>();

int[] array = list.stream().mapToInt(Integer::intValue).toArray();

 

ArrayList to Array

String[] arr = {"a","b","c","d"};
List<String> list = Arrays.asList(arr);

steam

int[] arr = {1,2,3};
List<Integer> list = Arrays.stream().boxed().collect(Collectors.toList());