Writing the reverse from i to 0 inside the forward loop from 0 to n. Example in Insertion Sort we are using this kind of loop.....

forward_reverse_loop.java

public class Main {
    public static void main(String[] args) {
        int[] input = {6,5,3,1,8,7,2,4};
        int j;
        for (int i = 1; i < input.length; i++) {
            // From 1 to n loop with index as i
            j = i - 1;
            while (j >= 0) {
                // From i to 0 with index as j
                System.out.println(j);
                j--;
            }
        }
    }
}