Why is last condition not satisfied

package com.codegym.task.task16.task1607; import java.util.ArrayList; import java.util.List; /* Horse racing */ public class Solution { public static void main(String[] args) throws InterruptedException { List<Horse> horses = prepareHorsesAndStart(10); while (calculateHorsesFinished(horses) != horses.size()) { } } public static int calculateHorsesFinished(List<Horse> horses) throws InterruptedException { int finishedCount = 0; for (int i = 0; i < horses.size(); i++) { if (horses.get(i).isFinished()) { finishedCount++; } else { System.out.println("Waiting for " + horses.get(i).getName()); horses.get(i).join(); } } return finishedCount; } public static List<Horse> prepareHorsesAndStart(int horseCount) { List<Horse> horses = new ArrayList<>(horseCount); String number; for (int i = 1; i < horseCount + 1; i++) { number = i < 10 ? ("0" + i) : "" + i; horses.add(new Horse("Horse_" + number)); } for (int i = 0; i < horseCount; i++) { horses.get(i).start(); } return horses; } public static class Horse extends Thread { private boolean isFinished; public Horse(String name) { super(name); } public boolean isFinished() { return isFinished; } public void run() { String s = ""; for (int i = 0; i < 1001; i++) { // Delay s += "" + i; if (i == 1000) { s = " has finished the race!"; System.out.println(getName() + s); isFinished = true; } } } } }