package threadsissue;

import java.util.logging.Level;
import java.util.logging.Logger;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.TextArea;
import javafx.scene.layout.Pane;
import javafx.stage.Stage;

public class Main extends Application {

    public static void main(String[] args) {
        launch(args);
    }
    String text = "one two three four five";

    @Override
    public void start(Stage stage) throws Exception {
        final TextArea tf = new TextArea(text);
        tf.setPrefSize(50, 50);

        new Thread(new Runnable() {

            public void run() {
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException ex) {
                    Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
                }
                for (int i = 1; i < 10; i++) {
                    for (int j = 0; j < text.length() + 1; j++) {
                        final int parameter = j;
                        com.sun.javafx.application.PlatformImpl.runAndWait(new Runnable() {

                            public void run() {
                                tf.positionCaret(parameter);
                                tf.selectPreviousWord();
                            }
                        });
                        try {
                            Thread.sleep(100);
                        } catch (InterruptedException ex) {
                            Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
                        }
                        System.out.println("Selection : " + tf.getSelectedText());
                    }
                }
               
            }
        }).start();

        Pane vb = new Pane();
        vb.getChildren().addAll(tf);
        Scene scene = new Scene(vb, 300, 300);
        stage.setScene(scene);
        stage.show();
    }
}