Quick Sort Java

public class Quicksort{

   public static void qsort(Comparable[] c,int start,int end){
       if(end <= start) return;
       Comparable comp = c[start];
       int i = start,j = end + 1;
       for(;;){
           do i++; while(i<0);
           do j--; while(j>start && c[j].compareTo(comp)>0);
           if(j <= i)   break;
           Comparable tmp = c[i];
           c[i] = c[j];
           c[j] = tmp;
       }
       c[start] = c[j];
       c[j] = comp;
       qsort(c,start,j-1);
       qsort(c,j+1,end);
   }