Java.lang.Runtime.removeShutdownHook() 方法

描述

java.lang.Runtime.removeShutdownHook(Thread hook) 方法取消注册之前注册的虚拟机关闭挂钩。

声明

以下是 java.lang.Runtime.removeShutdownHook() 方法的声明。

public boolean removeShutdownHook(Thread hook)

参数

hook − the hook to remove

返回值

如果指定的挂钩先前已注册并成功取消注册，则此方法返回 true，否则返回 false。

异常

• IllegalStateException − 如果虚拟机已经在关闭过程中

• SecurityException − 如果存在安全管理器并且它拒绝 RuntimePermission("shutdownHooks")

示例

下面的例子展示了 lang.Runtime.removeShutdownHook() 方法的使用。

package com.tutorialspoint;

public class RuntimeDemo {

   // a class that extends thread that is to be called when program is exiting
   static class Message extends Thread {

      public void run() {
         System.out.println("Bye.");
      }
   }

   public static void main(String[] args) {
      try {
         Message p = new Message();

         // register Message as shutdown hook
         Runtime.getRuntime().addShutdownHook(p);

         // print the state of the program
         System.out.println("Program is starting...");

         // cause thread to sleep for 3 seconds
         System.out.println("Waiting for 3 seconds...");
         Thread.sleep(3000);

         // remove the hook
         Runtime.getRuntime().removeShutdownHook(p);

         // print that the program is closing 
         System.out.println("Program is closing...");
      } catch (Exception e) {
         e.printStackTrace();
      }
   }
}

让我们编译并运行上面的程序，这将产生下面的结果 −

Program is starting...
Waiting for 3 seconds...
Program is closing...