Sorting in EJB

Question

At my wits end.
Currently I'm using CMP EJB-QL 2.0. I got a lot of problem sorting the return collection. whenever i insert this code into my Stateful ejb to perform the sorting, it always prompt error.
Collections.sort(productList, new Comparator() {
public int compare(Object o1, Object o2) {
ProductDetail product1 = (ProductDetail)o1;
ProductDetail product2 = (ProductDetail)o2;
return product1.getBrand().compareTo(product2.getBrand());
Error message:
java.rmi.ServerException: RemoteException occurred in server thread; nested exception is:
java.rmi.RemoteException: productController/ProductControllerBean$1
at com.sun.corba.ee.internal.javax.rmi.CORBA.Util.wrapException(Util.jav
a:350) at javax.rmi.CORBA.Util.wrapException(Util.java:277) at productController._ProductController_Stub.getAllProductsByBrand(Unkno
wn Source)
I tried to do basic sorting in the stateful session bean that extract data from the entity bean. ProductDetail is a helper class that implement io.java.io.Serializable. so is this possible the reason why i can't do the sorting?

Answer 1

the productList contain object of PollDetails. I insert collection return from entity bean to the pollList consist of pollDetails object.
My situation is like this
Stateful session bean access the entity bean. Entity bean return collection to session bean and session bean tries to sort the collection return by it. However, whenever i insert the comparator code into the session bean, it always prompt error... Any answer for that???
Comparator cmp = new Comparator() {
public int compare(Object o1, Object o2) {
String s1 = ((PollDetails)o1).getQuestion().toUpperCase();
String s2 = ((PollDetails)o1).getQuestion().toUpperCase();
return s1.compareTo(s2);
it always say unknown source.. but if i do all this in local environment it work perfectly...also if i remove this Collections.sort(productList, cmp).. the program work okay... So problem lies with session bean cannot manipulate collection??