Hi, i think your problem is here: @Persistent private List<B> list1 = new ArrayList<B>();
you use a List, but you assing an ArrayList. That because the datastore makes different structures for different types of collection. To fix that, your code should be: @Persistent private ArrayList <B> list1 = new ArrayList<B>(); Tell me if that solves your problem, bye! NM On Mon, Sep 21, 2009 at 9:41 AM, elDoudou <the.edouard.merc...@gmail.com>wrote: > > Thank you Maciej for your answer. > > But I think that my problem is not related to any empty field. The > problem of storage arises as soon as you define twice a persistent > field which is a list of the same type, as I explained earlier. The > only work-around I found is to duplicate the listed persistent class > (B), and have a "List<B'> list1" and a "List<B''> list2" (B' and B'' > being copy-classes of B): but since, you cannot properly persist > derived classes from persistent ones, I need to duplicate the code, > which is a shame! If someone by Google can explain this restriction, > this would help us a lot, and prevent from duplicating persistent > classes... > > Thank you for your help. Regards, > Édouard > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google App Engine for Java" group. To post to this group, send email to google-appengine-java@googlegroups.com To unsubscribe from this group, send email to google-appengine-java+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine-java?hl=en -~----------~----~----~----~------~----~------~--~---
