Integer[] spam = new Integer[] { 1, 2, 3 };
List<Integer> list = Arrays.asList(spam);
int[] spam = new int[] { 1, 2, 3 };
Arrays.stream(spam)
.boxed()
.collect(Collectors.toList());
List<Foo> list = new ArrayList<>();
Foo[] array = list.toArray(new Foo[0]);