한빛미디어

package com.test;

public class Sample34 {

        public static void main(String[] args) {
                
                int [][] arr= new int [5][5];
                int n=1;
                for (int i = 0; i < arr.length; i+=2) {
                        for (int j = 0; j < arr[i].length; j++) {
                                arr[i][j]=n++;
                                if (j==4) {
                                        for (int k = 4; k >= 0; k--) {
                                                arr[i+1][k]=n++;
                                                }
                                }
                        }
                }
                
                for (int i = 0; i < arr.length; i++) {
                        for (int j = 0; j < arr[i].length; j++) {
                                System.out.printf("%3d", arr[i][j]);
                        }
                        System.out.println();
                }
        }

}

  1  2  3  4  5
10  9  8  7  6
11 12 13 14 15
20 19 18 17 16
21 22 23 24 25

이렇게 출력되도록 짜본건데요.
논리적으로 오류는 없다고 생각하는데
오류가 나네요.
어느 부분이 잘못되었을까요?