hi i want implement Binary quicksort algorithm from robert sedgewick book it looks like this

  public class quickb{
public static final int bitsword=32;

public static void quicksortB(int a[],int l,int r,int d){
 int i=l;
int j=r-1;
if (r<=l || d>bitsword) return ;

 while (j!=i)
{

  while (digit(a[i],d)==0 && (i<j)) i++;
while (digit(a[j],d)==1 && (j>i)) j++;
   int t=a[i];
a[i]=a[j];
a[j]=t;
}
      if (digit(a[r-1],d)== 0) j++;

  quicksortB(a,l,j-1,d+1);
 quicksortB(a,j,r,d+1);




}

public static void main(String[]args){
   int a[]=new int[]{4,7,3,9,8,2};


 quicksortB(a,0,a.length-1,0);

 for (int i=0;i<a.length;i++){
  System.out.println(a[i]);
}



}

 public static int digit(int m,int d){


    return (m>>d)&1;



}
}

but it show me error:

java.lang.ArrayIndexOutOfBoundsException: 6
    at quickb.quicksortB(quickb.java:13)
    at quickb.main(quickb.java:32)

what is wrong?