Quick-Sort

My Quick Sort code in Java
import java.util.*;

public class qs { public static void main(String args[]) { int [] arr = {2, 3, 6, 5, 1, 4}; Quick_sort a = new Quick_sort(); a.qs(arr, 0, arr.length - 1);

    System.out.println("Sorted array: " + Arrays.toString(arr));
}

}

class Quick_sort { public void qs(int arr[], int p, int r) { if (p < r) { int q = partition(arr, p, r); qs(arr, p, q - 1); qs(arr, q + 1, r); } }

public int partition(int arr[], int p, int r) {
    int pivot = arr[r];
    int i = p - 1;

    for (int j = p; j < r; j++) {
        if (arr[j] <= pivot) {
            i++;
            swap(arr, i, j);
        }
    }

    swap(arr, i + 1, r);
    return i + 1;
}

public void swap(int arr[], int i, int j) {
    int temp = arr[i];
    arr[i] = arr[j];
    arr[j] = temp;
}

}