@Override
      ID initialize() {
        return invoke(invoke("NSNotificationCenter", "defaultCenter"),
                      "addObserver:selector:name:object:",
                      createDelegate("JBScrollBarStyleObserver", createSelector("handleScrollerStyleChanged:"), this),
                      createSelector("handleScrollerStyleChanged:"),
                      nsString("NSPreferredScrollerStyleDidChangeNotification"),
                      ID.NIL
        );
      }
@Override
      ID initialize()