code: protected Expression instantiate(Object oldInstance, Encoder out)
      {
          //
          // An implementation instance is actually constructed at decode time by calling
          // ControlBean.ensureControl on the parent bean.  This will create a new impl
          // instance and run the impl initializer on it.
          //
          return new Expression(((XMLEncoder)out).getOwner(), "ensureControl", null);
      }
docs: PersistenceDelegate.instantiate()