java - Linux 关机和 Java 关机 Hook

Question

当我在后台运行 Java 进程并关闭计算机 (ArchLinux) 时，计算机会等待几秒钟以终止我在 Java 中的关闭 Hook 吗？

Answer 1

如果你想在系统关闭时做一些事情，你需要添加一个关闭 Hook (假设你已经这样做了):

Runtime.getRuntime().addShutdownHook(
new Thread(new Runnable() {
    @Override
    public void run() {
        // This method will be executed and Virtual Machine will close when this method will return
    }
}));

如果花费太多时间，系统将永远等待完全终止

来自文档 Runtime#addShutdownHook

When the virtual machine is terminated due to user logoff or system shutdown the underlying operating system may only allow a fixed amount of time in which to shut down and exit. It is therefore inadvisable to attempt any user interaction or to perform a long-running computation in a shutdown hook.