Random value from 0 to MAX

randomFunction.java

   /**
     * Make an int random array with value from 0 to max
     * @param size: size = max + 1
     * @return result: an int array
     */
    private int[] makeRandomArray(int size) {
        int result[] = new int[size];
        List<Integer> ascesdingArray = new ArrayList<>();
        for (int i = 0; i < size; i++) {
            ascesdingArray.add(i);
        }
        for (int i = 0; i < size; i++) {
            int randomValue = random(ascesdingArray);
            result[i] = randomValue;
        }
        return result;
    }

    /**
     * Get random value in input array
     * @param ascesdingArray
     * @return randomValue: random element from input array
     */
    private int random(List<Integer> ascesdingArray) {
        int max = ascesdingArray.size() - 1;
        int randomValue = 0;
        if (max > 0) {
            // get random index and it's value
            int index = new Random().nextInt(max);
            randomValue = ascesdingArray.get(index);
            // remove value got from array so it will not be duplicated
            ascesdingArray.remove(index);
        } else if (max == 0) {
            randomValue = ascesdingArray.get(0);
        }
        return randomValue;
    }