while(!turtles.isEmpty()){

 	Iterator<RaceTurtle> it = new turtles.Iterator();

 	while(it.hasNext()){

            RaceTurtle turtle = it.next();
            RaceWindow.delay(10);

            if(turtle.getX()>=RaceWindow.X_END_POS){
                    turtles2.add(turtle);
                    it.remove();
            }
    	}
}