ObjectContext childContext = context.createChildContext();
// make sure we fetch in predictable order
SelectQuery query = new SelectQuery(Painting.class);
query.addOrdering(Painting.PAINTING_TITLE_PROPERTY, SortOrder.ASCENDING);
List objects = childContext.performQuery(query);
assertEquals(6, objects.size());
Painting childModifiedSimple = (Painting) objects.get(0);
childModifiedSimple.setPaintingTitle("C_PT");