Quick-Sort example in java

import java.util.*;

public class QuickSortExample {
public static void main(String[] args) {
Date now = new Date();
System.out.println("Now: " + now);
int arr[]={12,9,13,6,4,10};
int n=arr.length;
System.out.println("Array before swapping:");
printArray(arr);
System.out.println("Array after swapping:");
quickSort(arr,0,n-1);
printArray(arr);
}
static void swap(int []arr,int i,int j)
{
int temp=arr[i];
arr[i]=arr[j];
arr[j]=temp;
}
static int partition(int[] arr,int low,int high)
{
int pivot=arr[high];
int i=low-1;
for(int j=low;j<=high-1;j++)
{
if(arr[j]<pivot)
{
i++;
swap(arr,i,j);
}
}
swap(arr,i+1,high);
return (i+1);
}
static void quickSort(int arr[],int low,int high)
{
if(low<high)
{
int pi=partition(arr,low,high);
quickSort(arr,low,pi-1);
quickSort(arr,pi+1,high);
}
}
static void printArray(int []arr)
{
for(int i=0;i<arr.length;i++)
{
System.out.print(arr[i]+" ");
}
System.out.println();
}
}