//With Commons.Lang, you could simply use
ArrayUtils.reverse(int[] array)
// For reversing subarray
ArrayUtils.reverse(int[] array,int startIndexInclusive, int endIndexExclusive)
while(num != 0)
{
int digit = num % 10;
reversed = reversed * 10 + digit;
num /= 10;
}import java.util.*;
import java.util.stream.Collectors;
int[] array = new int[] {23, 54, 12};
List<Integer> list = Arrays.stream(array).boxed().collect(Collectors.toList());
Collections.reverse(list);
array = list.stream().mapToInt(x -> x).toArray();
//array = [12,54,23]WWWWW-
S---W-
W-W-W-
W-W---
E-W-W-
WWWWW-