Problema con las sesiones

[hayate]

Este es el codigo

Código:

public class booking   {
                 private String origin;
                 private String destiny;
                 private int adult;
                 private int child;
                 private int baby;
                 private Date date_departure;
                 private Time time;
                 private String cod_route;
                 private double cost;
                 private String coin;
                 private double total;
                 private String cod_fly;

                 public booking(String or,String de,int ad,int ch,int ba,Date dd,Time _time,String ro,String codFly,double _cost,String _coin, double _total){
                     origin=or;
                     destiny=de;
                     adult=ad;
                     child=ch;
                     baby=ba;
                     date_departure=dd;
                     time=_time;
                     cod_route=ro;
                     cod_fly=codFly;
                     cost=_cost;
                     total=_total;
                     coin=_coin;
                     }

        public String getOrigin() {
            return origin;
        }

        public String getDestiny() {
            return destiny;
        }

        public int getAdult() {
            return adult;
        }

        public int getChild() {
            return child;
        }   
        public int getBaby() {
            return baby;
        }
        public Date getDate_departure() {
            return date_departure;
        }
        public String getCod_route() {
            return cod_route;
        }
        public double getCost() {
            return cost;
        }
        public Time getTime() {
            return time;
        }
        public double getTotal() {
            return total;
        }
        public String getCoin() {
            return coin;
        }
        public String getCodFly(){
            return cod_fly;
        }
        public void setTotal(double to){
            total=to;
        }

       
        @Override
        public String toString() {
            return "dataroute{" + "origin=" + origin + ", destiny=" + destiny + ", adult=" + adult + ", child=" + child + ", date_departure=" + date_departure +'}';
        }
                
               
           }
 ArrayList booking1=new ArrayList();
booking1.add(new booking(ori,des,adu,chil,bab,_caldp,_time,co_route,fly_cod,_cost,coinor,totalCost));
HttpSession session = request.getSession(true);
                                    session.setAttribute("booking1",booking1);

he probado a meterle el implement serializable pero me da el mismo error