[Aglet]java.lang.ClassCastException in Vector

Question

Hi All,
I sometime get the ClassCastException in the Master agent when Slave return a vector as an arg to the Master agent in Aglet Programming. The code is attached.
The exception do not always exist that make me feel confusing about the exception.
does anyone ever got this kind of error?
Thanks for you any help!!
Poor Leo
public class Slave extends Aglet implements Serializable{
     public boolean handleMessage(Message m) {
          if (m.sameKind("tell")) {
               Vector vStore = new Vector();
               Cart shopCart = new Cart();
               shopCart.noOfItem =1;
               vStore.addElement(shopCart);
               try {
                    Message ack = new Message("ack");
                    ack.setArg("VSTORE", vStore);
                    masterproxy.sendFutureMessage(ack);
               }catch (Exception e){}
public class Master extends Aglet implements Serializable{
     public boolean handleMessage(Message m) {
          if (m.sameKind("ack")) {
               Vector vStore = new Vector();
               VStore = (Vector)m.getArg("VSTORE");     
               //***********ClassCastException sometime occur here********
               Cart cart = (Cart)Vstore.elementAt(0);
               //***********ClassCastException sometime occur here********
public class Cart implements Serializable{
     int noOfItem = 0;
Hashtable replyInfo = new Hashtable();
}

Answer 1

hi,
well i cant think of why an object in a Vector at one end should get transformed to something else at the other end,... but you could try the following. at the server end, after you retrieve the object
Object obj = Vstore.elementAt(0);        print the object using
System.out.println("obj is :" + obj); this will print a object reference, but you will be able to figure out what the object represents..
My guess is that somehow u are adding something else also to the Vector (maybe a null value is getting put into the vector).. check the value present in the Vector just before sending it to the Server.. log it in some file
hope that helps
cheerz
ynkrish