/*
В убывающем порядке
*/
public class Solution {
    public static void main(String[] args) throws Exception {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        int[] array = new int[20];
        for (int i = 0; i < 20; i++) {
            array[i] = Integer.parseInt(reader.readLine());
        }

        sort(array);

        for (int x : array) {
            System.out.println(x);
        }
    }

    public static void sort(int[] array) {
        //напишите тут ваш код
        Integer[] arrayInteger = new Integer[array.length];
        Arrays.sort(arrayInteger, Collections.reverseOrder());  // тут ругается
    }
}
Ошибка: Exception in thread "main" java.lang.NullPointerException at java.util.Collections$ReverseComparator.compare(Collections.java:5117) at java.util.Collections$ReverseComparator.compare(Collections.java:5108) at java.util.TimSort.countRunAndMakeAscending(TimSort.java:355) at java.util.TimSort.sort(TimSort.java:220) at java.util.Arrays.sort(Arrays.java:1438) at com.javarush.task.task07.task0728.Solution.sort(Solution.java:39) at com.javarush.task.task07.task0728.Solution.main(Solution.java:20)