Java - Quick Sort

public static long quickSort(int[] list) {
    quickSortHelper(list, 0, list.length - 1);
    return list;
}

public static void quickSortHelper(int[] list, int bottom, int top) {
    if(bottom < top) {
        int midpoint = partition(list, bottom, top);
        quickSortHelper(list, bottom, midpoint - 1);
        quickSortHelper(list, midpoint + 1, top);
    }
}

protected static int partition(int[] list, int bottom, int top) {
    int pivot = list[top];
    int firstAfterSmall = bottom;
    for(int i = bottom; i < top; i++) {
        if(list[i] <= pivot) {
            swap(list, firstAfterSmall, i);
            return firstAfterSmall;
        }
    }
    swap(list, firstAfterSmall, top);
    return firstAfterSmall;
}

protected static void swap(int[] list, int i, int j) {
    int temp = list[i];
    list[i] = list[j];
    list[j] = temp;
}