# 问题复现
for (int i = 0; i < 100; i++) { new Thread(new OrderService()).start(); } public class OrderService implements Runnable { private OrderNumGenerator orderNumGenerator = new OrderNumGenerator(); // private Lock lock = new ReentrantLock(); private Lock lock = new ZkLock(); @Override public void run() { getNumber(); } private void getNumber() { try { lock.getLock(); // lock.lock(); String number = orderNumGenerator.getNumber(); System.out.println(Thread.currentThread().getName() + ",获取的number:" + number); } catch (Exception e) { throw new RuntimeException(e); } finally { lock.unlock(); } } }
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输出
这里线程的名字已经超过100了,按理来说最大应该是100才对?
# 解决
以下是thread的源码
private static int threadInitNumber; private static synchronized int nextThreadNum() { return threadInitNumber++; }
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因为OrderService类也继承了Runnable接口,所以这个threadInitNumber变量被初始化了两次。😅