code: public static void shuffle( byte []array , int offset , int length , Random rand ) {
  		for (int i = 0; i < length; i++) {
  			int src = rand.nextInt(length-i);
  			byte tmp = array[offset+src+i];
  			array[offset+src+i]=array[offset+i];
  			array[offset+i] = tmp;
  		}
  	}
docs: Randomly shuffle the array