bson/src/main/org/bson/codecs/UuidCodecHelper.java
public static void reverseByteArray(final byte[] data, final int start, final int length) {
        for (int left = start, right = start + length - 1; left < right; left++, right--) {
            // swap the values at the left and right indices
            byte temp = data[left];
            data[left]  = data[right];
            data[right] = temp;
        }
    }
public static void reverseByteArray(final byte[] data, final int start, final int length) {
        for (int left = start, right = start + length - 1; left < right; left++, right--) {
            // swap the values at the left and right indices
            byte temp = data[left];
            data[left]  = data[right];
            data[right] = temp;
        }
    }
reverse elements in the subarray data[start:start+length]