at com.itheima.Demo1Application.main(Demo1Application.java:10) ~[classes/:na]

This is a stack trace that is printed when an exception is thrown in a Java program. It indicates that an exception occurred in the "main" method of the "Demo1Application" class, at line 10 of the source code. The "~[classes/:na]" part indicates that the exception occurred in a compiled class file and not in the original source code. The exact cause of the exception can be determined by analyzing the exception message and the code around the line number indicated in the stack trace.

相关问题

Exception in thread "饿汉1" java.lang.IllegalMonitorStateException: current thread is not owner at java.base/java.lang.Object.wait(Native Method) at java.base/java.lang.Object.wait(Object.java:338) at com.itheima.d7_thread_communication.Desk.get(Desk.java:33) at com.itheima.d7_thread_communication.ThreadTest.lambda$main$3(ThreadTest.java:24) at java.base/java.lang.Thread.run(Thread.java:833) Exception in thread "饿汉2" java.lang.IllegalMonitorStateException: current thread is not owner at java.base/java.lang.Object.wait(Native Method) at java.base/java.lang.Object.wait(Object.java:338) at com.itheima.d7_thread_communication.Desk.get(Desk.java:33) at com.itheima.d7_thread_communication.ThreadTest.lambda$main$4(ThreadTest.java:27) at java.base/java.lang.Thread.run(Thread.java:833)

这个错误是 IllegalMonitorStateException，意思是当前线程不是锁的拥有者，不能进行wait或notify操作。在你的代码中，线程在 Desk 类的 get() 方法中调用了 wait() 方法，但是没有先获取锁，因此抛出了该异常。

要解决这个问题，你需要在调用 wait() 方法之前先获取锁，可以使用 synchronized 关键字来实现。在 Desk 类的 get() 方法中，将 wait() 方法调用放在一个 synchronized 块中，如下所示：

public synchronized void get() {
    while (flag == false) {
        try {
            wait();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
    System.out.println("取走：" + this.name + "-" + this.sex);
    flag = false;
    notify();
}

这样，当线程调用 get() 方法时，会先获取 Desk 对象的锁，然后再调用 wait() 方法等待。当其他线程调用 put() 方法并修改了 flag 值后，会调用 notify() 方法唤醒等待的线程。唤醒后，该线程会重新尝试获取锁并继续执行代码。

Exception in thread "main" java.lang.ExceptionInInitializerError at com.itheima.dao.impl.ResterauntDaoImpl.<clinit>(ResterauntDaoImpl.java:20) at com.itheima.service.impl.ResterauntServiceImpl.<clinit>(ResterauntServiceImpl.java:14) at com.itheima.service.impl.UserServiceImpl.<clinit>(UserServiceImpl.java:15) at Main.Test2.main(Test2.java:8) Caused by: java.lang.NullPointerException: Cannot invoke "java.util.Collection.add(Object)" because "c" is null at java.base/java.util.Collections.addAll(Collections.java:5624) at com.itheima.dao.impl.OrderDaoImpl.<clinit>(OrderDaoImpl.java:33) ... 4 more

这是一个 Java 异常，看起来是在初始化程序时出错了。具体来说，是在 `ResterauntDaoImpl` 类的静态初始化块中的第 20 行发生了错误，导致整个类初始化失败，进而导致 `ResterauntServiceImpl` 和 `UserServiceImpl` 类的初始化也失败了。从异常信息中我们可以看到，问题出在一个空指针异常上，`c` 对象为 null，导致在调用 `add` 方法时出现了空指针异常。需要检查 `c` 对象是在哪里被初始化的，是否被正确地初始化了。