Use AnimationTimer.

src/main/java/lab/App.java

 package lab;
 
+import javafx.animation.AnimationTimer;
 import javafx.application.Application;
 import javafx.scene.Group;
 import javafx.scene.Scene;
 import javafx.scene.canvas.Canvas;
-import javafx.scene.canvas.GraphicsContext;
 import javafx.stage.Stage;
 import javafx.stage.WindowEvent;
 
@@ -19,6 +19,7 @@ public class App extends Application {
 	}
 	
 	private Canvas canvas;
+	private AnimationTimer timer;
 	
 	@Override
 	public void start(Stage primaryStage) {
@@ -36,27 +37,16 @@ public class App extends Application {
 			
 			//Exit program when main window is closed
 			primaryStage.setOnCloseRequest(this::exitProgram);
-			
-			//Draw scene on a separate thread to avoid blocking UI.
-			new Thread(this::drawScene).start();
+			timer = new DrawingThread(canvas);
+			timer.start();
 		} catch (Exception e) {
 			e.printStackTrace();
 		}
 	}
-	
-	/**
-	 * Draws objects into the canvas. Put you code here. 
-	 *
-	 *@return      nothing
-	 */
-	private void drawScene() {
-		//graphic context is used for a painting
-		GraphicsContext gc = canvas.getGraphicsContext2D();
-		int timeout = 10;
-		while (!Routines.isEndOfThreadRequestedByJavaVM()) {
-			Routines.sleep(timeout);
-			double deltaT = timeout / 1000.;
-		}
+	@Override
+	public void stop() throws Exception {
+		timer.stop();
+		super.stop();
 	}
 	
 	private void exitProgram(WindowEvent evt) {

src/main/java/lab/Bullet.java

+package lab;
+
+import javafx.geometry.Point2D;
+import javafx.scene.canvas.GraphicsContext;
+import javafx.scene.paint.Color;
+
+public class Bullet {
+	private World world;
+	private Point2D velocity;
+	private double size;
+	private Point2D position;
+	public Bullet(World world, Point2D startPosition, Point2D velocity, double size) {
+		super();
+		this.world = world;
+		this.velocity = velocity;
+		this.size = size;
+		this.position = startPosition;
+	}
+	
+	public void draw(GraphicsContext gc) {
+		gc.save();
+		gc.setFill(Color.BROWN);
+		Point2D p = world.getCanvasPoint(position);
+			gc.fillOval(p.getX() - size /2, p.getY() - size/2, size, size);
+		gc.restore();
+	}
+
+	public void simulate(double deltaT) {
+		// TODO Auto-generated method stub
+		position = position.add(velocity.multiply(deltaT));
+	}
+	
+	
+}

src/main/java/lab/DrawingThread.java

+package lab;
+
+import javafx.animation.AnimationTimer;
+import javafx.scene.canvas.Canvas;
+import javafx.scene.canvas.GraphicsContext;
+
+public class DrawingThread extends AnimationTimer {
+
+	private final GraphicsContext gc;
+	private final World world;
+	private long lastTime;
+
+	public DrawingThread(Canvas canvas) {
+		this.gc = canvas.getGraphicsContext2D();
+		this.world = new World(canvas.getWidth(), canvas.getHeight());
+	}
+
+	/**
+	  * Draws objects into the canvas. Put you code here. 
+	 */
+	@Override
+	public void handle(long now) {
+		if (lastTime > 0) {
+			double deltaT = (now - lastTime) / 1e9;
+			world.simulate(deltaT);
+		}
+		world.draw(gc);
+		lastTime= now;
+
+	}
+
+}

src/main/java/lab/World.java

+package lab;
+
+import javafx.geometry.Point2D;
+import javafx.scene.canvas.GraphicsContext;
+import javafx.scene.paint.Color;
+
+public class World {
+	
+	private double width;
+	
+	private double height;
+
+	private Bullet bullet;
+
+	
+	public World(double width, double height) {
+		this.width = width;
+		this.height = height;
+		this.bullet = new Bullet(this, new Point2D(10, 10), new Point2D(10, 30), 15);
+	}
+	
+	public Point2D getCanvasPoint(Point2D in) {
+		Point2D result = new Point2D(in.getX(), height - in.getY());
+		return result;
+	}
+	
+	public void draw(GraphicsContext gc) {
+		gc.save();
+		gc.setFill(Color.LIGHTGREY);
+		gc.fillRect(0, 0, width, height);
+		gc.restore();
+		bullet.draw(gc);
+	}
+	
+	public void simulate(double deltaT) {
+		this.bullet.simulate(deltaT);
+	}
+}