How do I use Java getResource() to get a resource from a parent directory?

I've tried numerous methods now, including FilenameUtils.normalize() from commons IO, but I can't seem to be able to get a resource in another folder to get a Java FXML file.

The code is the following

  try {
     root = FXMLLoader.load(getClass().getResource("../plugin/PluginSelection.fxml"));
  } catch (IOException ex) {
     Logger.getLogger(QueueOperationsController.class.getName()).log(Level.SEVERE, null, ex);
  }

Where the desired FXML file is:

gui
   dialogues
      plugins
         PluginSelection.fxml // desired file
      dataset
         QueueOperationsController // current class

How do I best get the desired file's URL?

Thank you!