public void concUpdate(ExtObjectContainer oc, int seq) throws Exception {
   Query q = oc.query();
   q.constrain(IndexedByIdentityTestCase.class);
   ObjectSet os = q.execute();
   Assert.areEqual(COUNT, os.size());
   while (os.hasNext()) {
     IndexedByIdentityTestCase idi = (IndexedByIdentityTestCase) os.next();
     idi.atom.name = "updated" + seq;
     oc.store(idi);
     Thread.sleep(100);
   }
 }