Quick sort and Merge sort

Quick sort and Merge sort - both use recursion.

import java.util.*;
public class qs {

  int recursionCount = 0;

  void quickSort(int arr[]) {
    recursionCount = 0;
    quickSort(arr, 0, arr.length-1);
  }

  void quickSort(int arr[], int left, int right) {
    int i = left, j = right;
    int tmp;
    int pivot = arr[(left + right) / 2];
    recursionCount++;
    /* partition */
    while (i <= j) {
      while (arr[i] < pivot)
        i++;
      while (arr[j] > pivot)
        j--;
      if (i <= j) {
        tmp = arr[i];
        arr[i] = arr[j];
        arr[j] = tmp;
        i++;
        j--;
      }
    }

    /* recursion */
    if (left < j)
      quickSort(arr, left, j);
    if (i < right)
      quickSort(arr, i, right);
  }

  void mergeSort(int arr[]) {
    recursionCount = 0;
    mergeSortR(arr);
  }

  int [] mergeSortR(int arr[]) {
    if (arr.length > 1) { // split into two halves
      recursionCount++;
      int sizeL = arr.length/2;
      int sizeR = arr.length - sizeL;
      int arrL[] = new int[sizeL];
      int arrR[] = new int[sizeR];
      for(int i=0; i<sizeL; i++) arrL[i] = arr[i];
      for(int i=sizeL; i<sizeL+sizeR; i++) arrR[i-sizeL] = arr[i];
      /* recursion */
      arrL = mergeSortR(arrL);
      arrR = mergeSortR(arrR);

      int i = 0, j = 0, k = 0;
      while(arrL.length != j && arrR.length != k) {
        if(arrL[j] < arrR[k]) {
          arr[i] = arrL[j];
          i++;
          j++;
        } else {
          arr[i] = arrR[k];
          i++;
          k++;
        }
      }
      while(arrL.length != j) {
        arr[i] = arrL[j];
        i++;
        j++;
      }
      while(arrR.length != k) {
        arr[i] = arrR[k];
        i++;
        k++;
      }
    }
    return arr;
  }

  public qs(){
  }

  
  int arr[];
  int arrCopy[];
  public void init() {
    System.out.println(""+getAppletInfo());
    System.out.println("quick sort before..., count:"+arr.length);
    print();
    quickSort(arr);
    System.out.println("after...");
    print();
    System.out.println("recursionCount:"+recursionCount);

    for(int i=0; i<arrCopy.length; i++) {
      arr[i] = arrCopy[i];
    }
    System.out.println("merge sort, before..., count:"+arr.length);
    print();
    mergeSort(arr);
    System.out.println("after...");
    print();
    System.out.println("recursionCount:"+recursionCount);

  }

  public void print() {
    for(int i=0; i<arr.length; i++) {
      System.out.print(","+arr[i]);
    }
    System.out.println("");
  }

  public String getAppletInfo() {
    return "quicksort by Douglas A. Bauman";
  }

  static public void main(String[] args) {
    qs qsi = new qs();
    qsi.arr = new int[args.length];
    qsi.arrCopy = new int[args.length];
    boolean valid = args.length > 0;
    for(int i=0; i<args.length; i++) {
      try{
        qsi.arr[i] = (new Integer(args[i])).intValue();
        qsi.arrCopy[i] = qsi.arr[i];
      }catch (NumberFormatException e) {
        System.out.println("args["+i+"], not a number: "+args[i]);
        valid = false;
      }
    }
    if (valid)
      qsi.init();
  }
}