Quicksort Algorithm in Java

QuickSortAlgo.java

public class QuickSortAlgo{

     
     private void quicksort(int [] arr, int first, int last)
     {
         int left = first, pivot = first, right = last, temp;
         if (first<last)
         {
             while(left<right)
             {
                 while(arr[left] <= arr[pivot] && left < last)
                 left++;
                 while(arr[right] > arr[pivot])
                 right--;
                 if(left<right)
                 {
                     temp = arr[left];
                     arr[left] = arr[right];
                     arr[right] = temp;
                     left++;
                     right--;
                 }
                 
             }
             temp = arr[pivot];
             arr[pivot] = arr[right];
             arr[right] = temp;
             quicksort(arr, first, right-1);
             quicksort(arr, right+1, last);
         }
                          
     }
         
     
     public static void main(String []args){
         
         int [] arr = { 34, 4,67,4,23,65,34,37,73,34,2,7,34};
         
         for (int i=0;i<arr.length-1;i++)
         System.out.print(" " +arr[i]);
         
         QuickSortAlgo q = new QuickSortAlgo();
         q.quicksort(arr, 0, arr.length-1);
         
         System.out.println();
         for (int i=0;i<arr.length-1;i++)
         System.out.print(" " +arr[i]);
         
     }
}