code: @Override
      @Deprecated
      public boolean add(T t) {
          try {
              return addSync(t);
          } finally {
              if(extensions!=null) {
                  fireOnChangeListeners();
              }
          }
      }
docs: Write access will put the instance into a legacy store.
  
  @deprecated since 2009-02-23.
  Prefer automatic registration.