K번째수(for JAVA)

import java.util.*;

class Solution {
    public int[] solution(int[] array, int[][] commands) {
        int[] answer = new int[commands.length];
        int k = 0;
        for(int i=0;i<commands.length;i++){
            int[] command = commands[i];
            int start = command[0];
            int end = command[1];
            int sequence = command[2];
            ArrayList<Integer> arr = new ArrayList<>();
            for(int a=start-1;a<end;a++){
                arr.add(array[a]);
            }
            Collections.sort(arr);
            answer[k++] = arr.get(sequence-1);
        }
        return answer;
    }
}

콜렉션 소팅 함수 에다 자꾸 배열 소팅 함수를 쓰고 난리다. 나참