Java Java.lang.Runtime.removeShutdownHook()用法及代碼示例

描述

這個java.lang.Runtime.removeShutdownHook(Thread hook)方法 de-registers 一個 previously-registered virtual-machine 關閉鉤子。

聲明

以下是聲明java.lang.Runtime.removeShutdownHook()方法

public boolean removeShutdownHook(Thread hook)

參數

hook- 要移除的鉤子

返回值

如果指定的鉤子先前已注冊並且成功 de-registered，則此方法返回 true，否則返回 false。

異常

• IllegalStateException− 如果虛擬機已經在關閉過程中

• SecurityException− 如果存在安全管理器並且拒絕 RuntimePermission("shutdownHooks")

示例

下麵的例子展示了 lang.Runtime.removeShutdownHook() 方法的用法。

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();
      }
   }
}

讓我們編譯並運行上麵的程序，這將產生以下結果 -

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