//冒泡排序public static int[] bubbleSort(int[] arr){    int length = arr.length;    for(int i = 0;i
     
      arr[j]){                int t = arr[i];                arr[i] = arr[j];                arr[j] = t;            }        }    }    return arr;}
     

// 测试public static void main(String[] args){    int[] arr = {4,2,3,1};    int[] newArr = bubbleSort(arr);    for (int num:newArr) {        System.out.println(num);    }}