新人问一下 Java 多线程的问题。

 class Hero { private String name; public int hp = 10; public Hero(String str) { this.name = str; } public synchronized void recover() { this.hp += 1; } public synchronized void hurt() { this.hp -= 1; } } public class Test { public static void main(String[] args) { Hero garen = new Hero("garen"); // 线程一 new Thread(() -> { System.out.println(Thread.currentThread().getName() + "...."); while (true) { while (garen.hp == 1) { continue; } try { Thread.sleep(200); garen.hurt(); System.out.println(Thread.currentThread().getName() + "..." + "hp down-" + garen.hp); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }).start(); // 线程二 new Thread(() -> { while (true) { if (garen.hp == 20) { continue; } try { Thread.sleep(400); garen.recover(); System.out.println(Thread.currentThread().getName() + "....." + "hp up-" + (garen.hp)); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }).start(); } } 

为什么线程一不执行了？是因为没有更新 garen.hp 的值吗？