Look in the log (at DEBUG level) and see if the List field is replaced by a wrapper type when you retrieve the overall object from the datastore. Alternatively, print out the getClass() of the List object before your update.
If it isn't of type "org.datanucleus.sco.XXXX" then the error is in GAE/J not replacing the field with a wrapper before handing it back to the user (and issue was raised on it some time ago for that). See http://code.google.com/p/datanucleus-appengine/issues/detail?id=144&colspec=ID%20Stars%20Type%20Status%20Priority%20FoundIn%20TargetRelease%20Owner%20Summary if that is your case
-- 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 [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine-java?hl=en.
