QuickSort ArrayList

import java.util.ArrayList;


public class QuickSort {

    ArrayList<Integer>  array;
    int leng;
    int mov = 0, comp = 0;

    public static void main(String a[]){
        ArrayList<Integer> arreglo = new ArrayList<Integer>();
        QuickSort p1 = new QuickSort();
        System.out.println("Desordenado ");
        for(int i=0; i<100; i++){
            arreglo.add((int)(Math.random()*200));
            System.out.print(arreglo.get(i)+" ");

        }
        System.out.println();

        p1.array = arreglo;
        p1.leng = arreglo.size();
        p1.quickSort(0, p1.leng - 1);
        System.out.println("Ordenado ");
        for(int i=0; i<100; i++){
            System.out.print(arreglo.get(i)+" ");

        }
        System.out.println("\nComparaciones: "+p1.comp+"\nMovimientos: "+p1.mov);


    }


    private void quickSort(int lowerI, int upperI) {

        int i = lowerI;
        int j = upperI;

        int pivote = array.get(lowerI+(upperI-lowerI)/2);

        while (i <= j) {

            while (array.get(i) < pivote) {
                i++;
                comp++;
            }
            while (array.get(j) > pivote) {
                j--;
                comp++;
            }
            if (i <= j) {
                interNumbers(i, j);

                i++;
                j--;
            }
        }

        if (lowerI < j)
            quickSort(lowerI, j);
        if (i < upperI)
            quickSort(i, upperI);
    }

    public void interNumbers(int i, int j) {
        int temp = array.get(i);
        array.set(i, array.get(j));
        array.set(j, temp);
        mov++;
    }


}