Solution Review: Gathering Zeros to the Start

class ArrList {
    public static void zerosToStart(ArrayList < Integer > arrList) {
        ArrayList < Integer > newArrayList = new ArrayList < Integer > ();
        int newArray_index = 0;

        //Fill newArrayList with Zeros first.
        //Then Fill it with non-zero Values.
        //In the end, insert every element of newArrayList back into origional arrList.
        for (int i = 0; i < arrList.size(); i++) {

            if (arrList.get(i) == 0)
                newArrayList.add(newArray_index++, arrList.get(i));
        }

        for (int i = 0; i < arrList.size(); i++) {

            if (arrList.get(i) != 0)
                newArrayList.add(newArray_index++, arrList.get(i));
        }

        for (int j = 0; j < newArrayList.size(); j++) {
            arrList.set(j, newArrayList.get(j));
        }
    }
    public static void main( String args[] ) {
       ArrayList<Integer> input = new ArrayList<Integer>(Arrays.asList(5, 0, 20, 4, 0, 0, 9));
       System.out.println("Array List before calling zerosToStart");
       for (int i = 0; i < input.size(); i++){
           System.out.print(input.get(i)+ "  ");
       }
       System.out.println();
       ArrList.zerosToStart(input);
       System.out.println("Array List after calling zerosToStart");
       for (int i = 0; i < input.size(); i++){
           System.out.print(input.get(i)+ "  ");
       }
       System.out.println();
    }
}