Tak už jsem na to došel.

package settlers_javafx;

import java.text.SimpleDateFormat;
import java.util.Date;
import javafx.animation.Timeline;
import javafx.geometry.Pos;
import javafx.scene.text.Font;

public final class Clock extends javafx.scene.control.Label {

    private final SimpleDateFormat SIMPLE_DATE_FORMAT;

    public Clock(String type, int x, int y, int width, int height) {
        setTextFill(javafx.scene.paint.Color.BLUE);
        setLayoutX(x);
        setLayoutY(y);
        setPrefSize(width, height);
        switch (type) {
            case "date":
                SIMPLE_DATE_FORMAT = new SimpleDateFormat("  MMMM dd yyyy");
                setFont(new Font("sans-serif", 12));
                setAlignment(Pos.CENTER_LEFT);
                break;
            case "time":
                SIMPLE_DATE_FORMAT = new SimpleDateFormat("hh:mm:ss a");
                setFont(new Font("sans-serif", 40));
                setAlignment(Pos.CENTER);
                break;
            case "day":
                SIMPLE_DATE_FORMAT = new SimpleDateFormat("EEEE  ");
                setFont(new Font("sans-serif", 16));
                setAlignment(Pos.CENTER_RIGHT);
                break;
            default:
                SIMPLE_DATE_FORMAT = new SimpleDateFormat();
        }
        Timeline timer = new Timeline(new javafx.animation.KeyFrame(javafx.util.Duration.seconds(1), (javafx.event.ActionEvent event) -> {
            Date d = new Date();
            setText(SIMPLE_DATE_FORMAT.format(d));
        }));
        timer.setCycleCount(Timeline.INDEFINITE);
        timer.play();
    }
}