Почему валидатор не принимает?

public class Hippodrome {
    private List<Horse> horses;

    public List<Horse> getHorses() {
        return horses;
    }

    public Hippodrome(List<Horse> horses) {
        this.horses = horses;
    }

    public static Hippodrome game;

    public static void main(String[] args) {
        Horse horse1= new Horse("Vitya",3,0);
        Horse horse2= new Horse("Galya",3,0);
        Horse horse3= new Horse("Dima",3,0);
        List <Horse> tempHorses = new ArrayList<Horse>();
        tempHorses.add(horse1);tempHorses.add(horse2);tempHorses.add(horse3);
        game = new Hippodrome(tempHorses);
        game.run();
        game.printWinner();


    }

    public void run() {
        for (int i=0; i<100; i++)
        {
            this.move();
            this.print();
            try {
                Thread.sleep(200);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
    public void move() {
        for (Horse tempHorse : this.getHorses()) {tempHorse.move();}
    }
    public void print() {
        for (Horse tempHorse : this.getHorses()){tempHorse.print();}
        for(int i=0;i<10;i++) System.out.println("");
    }
    public Horse getWinner()
    {
    Horse tempWinHorse = new Horse("Test",1,0);
        for (Horse tempHorse : game.getHorses()){if (tempHorse.distance>tempWinHorse.distance) tempWinHorse=tempHorse;}

        return tempWinHorse;
    }
    public void printWinner()
    {
        Horse winHorse = game.getWinner();
        System.out.println("Winner is "+winHorse.name+"!");

    }
}

public class Horse {
    public String name;
    public double speed;
    public double distance;

    public Horse(String name, double speed, double distance) {
        this.name = name;
        this.speed = speed;
        this.distance = distance;
    }

    public void setDistance(double distance) {
        this.distance = distance;
    }

    public void setSpeed(double speed) {

        this.speed = speed;
    }

    public void setName(String name) {

        this.name = name;
    }

    public double getDistance() {

        return distance;
    }

    public double getSpeed() {

        return speed;
    }

    public String getName() {

        return name;
    }
    public void move()
    {
        distance+= speed*Math.random();
    }
    public void print ()
    {
        int points = (int) Math.floor(distance);
        String tempString = ".";
        for (int i=1;i<points;i++) {tempString=tempString.concat(".");}
        System.out.println(tempString + name);

    }
}

public Horse getWinner()
   {
   Horse tempWinHorse = game.getHorses().get(0);
       for (Horse tempHorse : game.getHorses()){if (tempHorse.distance>tempWinHorse.distance) tempWinHorse=tempHorse;}

       return tempWinHorse;
   }