FXML_Controller

/**
 * Sample Skeleton for 'load_screen.fxml' Controller Class
 */

package Loader;

import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.nio.file.Paths;
import java.util.ResourceBundle;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;


import javafx.fxml.FXMLLoader;
import javafx.scene.text.Text;

public class Controller  implements Runnable {

    @FXML // ResourceBundle that was given to the FXMLLoader
    private ResourceBundle resources;

    @FXML // URL location of the FXML file that was given to the FXMLLoader
    private URL location;

    @FXML // fx:id="load_text"
    private Text load_text; // Value injected by FXMLLoader


    @Override
    public void run() {
        Platform.runLater(() ->  load_text.setText("Hello World"));


    }

    @FXML
    void initialize() throws IOException, InterruptedException {
        Controller loader= new Controller();
       Thread load=new Thread(loader);
       load.start();
        assert load_text != null : "fx:id=\"load_text\" was not injected: check your FXML file 'load_screen.fxml'.";
    }
}