Convert Array to List in Java

Java Array List primitive

Java version: 8

For object array:

    Integer[] nums = {1, 2, 3, 4};
    List<Integer> numList = Arrays.asList(nums);

For a primitive Array (need import java.util.stream.Collectors)

    int[] nums = {1, 2, 3, 4};
    List<Integer> numList = Arrays.stream(nums).boxed().collect(Collectors.toList());

Sort a primitive Array as descending order. It is not in space.

    int[] nums = {1, 2, 3, 4};
    int[] numsOrdered = Arrays.stream(nums).boxed().sorted(Comparator.reverseOrder()).mapToInt(i->i).toArray();

List to int[]

    int[] nums = {1, 2, 3, 4};
    List<Integer> numList = Arrays.stream(nums).boxed().collect(Collectors.toList());
    int[] array = numList.stream().mapToInt(i->i).toArray();

Written on January 30, 2018