public final Object activatedObject(int id) {
   ObjectContainerBase stream = stream();
   Object ret = stream.getActivatedObjectFromCache(_transaction, id);
   if (ret != null) {
     return ret;
   }
   return stream.readActivatedObjectNotInCache(_transaction, id);
 }
 public Object lock() {
   final ObjectContainerBase stream = stream();
   stream.checkClosed();
   return stream.lock();
 }