Java如何对整数数组进行排序？

public class SortArr {

    public static void sortAsc(int[] arr) {
        int temp = 0; //a variable to store temporary value while swapping
        for (int i = 0; i < arr.length-1; i++) { //for loop to hold the current element to be compared
            for (int j = i + 1; j < arr.length; j++) { //for loop to iterate over the other elements
                //to get them compared with the current element 
                if (arr[i] > arr[j]) { //if any of the higher index element is smaller than
                                       //the current element
                    temp = arr[i]; //store the current element to temp
                    arr[i] = arr[j]; //store the smaller element to the lower index position
                    arr[j] = temp; //store the current element to greater index position
                }
            }
        }
    }

    public static void main(String args[]) {
        int array[] = {5, 3, 1};
        System.out.println( "Array values before sorting:");
        for (int i = 0; i < array.length; i++) {
            System.out.print(array[i]+ "  ");
        }
        System.out.println();
        sortAsc(array);
        System.out.println( "Array values after sorting:");
        for (int i = 0 ; i < array.length; i++){
            System.out.print(array[i]+ "  ");
        }
    }
}

输出：

Array values before sorting:
5  3  1  
Array values after sorting:
1  3  5 

我一开始知道它比较 5 和 3，然后是 5 和 1，但是它如何比较 1 和 3？ 谁能解释一下？