Answers for "java list to int array"

list to int array in java 8

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

convert int array to integer list java

int[] arr = {1,2,3};
IntStream.of(arr).boxed().collect(Collectors.toList());

convert list of integer to array in java

List<Integer> al = new ArrayList<Integer>(); 
Integer[] arr = new Integer[al.size()]; 
arr = al.toArray(arr);