Java 为什么不调用wait方法后面的代码

我有一个customer account类，包含以下两种方法：addBalance和DecluttBalance

class CustomerAccount
{
    
    private int balance;
    int getBalance() { return balance;}
    CustomerAccount() {balance=0;}
    boolean deductBalance(final int amount)
    {
        System.out.println("> invoked to deduct :" + amount);
        synchronized (this)
        {
            while (balance <= amount)
            {
                try {wait(); } catch (InterruptedException e) {TestWaitNotifyBasic.logException(e);}
                System.out.println("> hey I was notified for cutting amount:" + amount);
            }
            balance-= amount;
        }
        System.out.println("> deducted:" + amount);
        return true;
    }
    boolean addBalance(final int amount)
    {
        synchronized (this)
        {
            balance += amount;
            notifyAll();
        }
        System.out.println("> balance added: " + amount);
        return true;
    }
}

我的问题是，为什么控制台输出中不打印下面的内容

> balance added: 80
> invoked to deduct :1000
> balance added: 8000
> invoked to deduct :5000
> invoked to deduct :50
> balance added: 900
> balance added: 40
> deducted:5000
> deducted:50
> deducted:1000
----------------------
thread operations finished, final balance : 2970
Validity check 2970

System.out.println（“>嘿，我收到了削减金额的通知：“+amount”）

此方法写在CustomerAccount类中Decrete balance方法的wait（）旁边。

在注释之后，在进入执行之前将addBalance线程修改为睡眠。在这之后，所有的系统输出都被执行了

上面发布的代码的行为是addBalance线程将在deductBalance线程进入同步块之前执行

使用下面的addBalance方法，ouptut会发生变化

boolean addBalance(final int amount)
    {
        try {Thread.sleep(3000);} catch (InterruptedException e) {{TestWaitNotifyBasic.logException(e);}}
        synchronized (this)
        {
            balance += amount;
            notifyAll();
        }
        System.out.println("> balance added: " + amount);
        return true;
    }

控制台输出post方法更改：

> invoked to deduct :50
> invoked to deduct :1000
> invoked to deduct :5000
> balance added: 900
> balance added: 40
> hey I was notified for cutting amount:50
> balance added: 8000
> balance added: 80
> hey I was notified for cutting amount:5000
> deducted:50
> hey I was notified for cutting amount:1000
> deducted:1000
> deducted:5000

----------------------
thread operations finished, final balance : 2970
Validity check 2970

---

永远不要写

catch（InterruptedException e）{}

。至少记录exception@Jens，这是练习用的。。不是生产代码。这不是让catch块为空的原因。您将永远看不到是否存在可以更改程序流的异常。可能的原因是，在“add 8000”之前，没有任何演绎线程进入同步块。因此，他们从未进入

而
循环。@Jens添加了异常日志记录。原始代码中没有问题，我只是想查看控制台输出。问题是“为什么控制台输出不可见”？这就是我的意思。当我运行您的原始代码时，我得到了您的预期输出，即，
>嘿，当我运行您的原始代码时，控制台中确实出现了削减金额的通知。
> invoked to deduct :50
> invoked to deduct :1000
> invoked to deduct :5000
> balance added: 900
> balance added: 40
> hey I was notified for cutting amount:50
> balance added: 8000
> balance added: 80
> hey I was notified for cutting amount:5000
> deducted:50
> hey I was notified for cutting amount:1000
> deducted:1000
> deducted:5000

----------------------
thread operations finished, final balance : 2970
Validity check 2970