java - 如何避免finally block 不执行的场景

Question

我在采访中被问到什么时候 finally block 不执行。我回答说，当 JVM 在调用 finally 之前或在调用 System.exit() 之前突然关闭时。然后有人问我如何才能避免这种情况，以便我们的程序始终保持执行状态。那就是应该处理这样的场景。我们能处理这样的场景吗？如果是如何？提前致谢。

Answer 1

即使 finally 失败，shutdownhook 也会被执行。

答案是——

Runtime#addShutdownHook

The Java virtual machine shuts down in response to two kinds of events:

• The program exits normally, when the last non-daemon thread exits or when the exit (equivalently, System.exit) method is invoked, or
• The virtual machine is terminated in response to a user interrupt, such as typing ^C, or a system-wide event, such as user logoff or
  system shutdown.

Java docs

代码-

Runtime.addShutdownHook(new Thread {
  public void run() {
    System.out.println("Just before going down..");
  });