Java.lang.Runtime.removeShutdownHook() Method

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Description

The java.lang.Runtime.removeShutdownHook(Thread hook) method de-registers a previously-registered virtual-machine shutdown hook.

Declaration

Following is the declaration for java.lang.Runtime.removeShutdownHook() method

public boolean removeShutdownHook(Thread hook)

Parameters

hook − the hook to remove

Return Value

This method returns true if the specified hook had previously been registered and was successfully de-registered, false otherwise.

Exception

• IllegalStateException − If the virtual machine is already in the process of shutting down

• SecurityException − If a security manager is present and it denies RuntimePermission("shutdownHooks")

Example

The following example shows the usage of lang.Runtime.removeShutdownHook() method.

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();
      }
   }
}

Let us compile and run the above program, this will produce the following result −

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