Shutdown hookup In Java

While terminating a program a thread can be invoked, such threads are called shutdown hookup. In this thread we can put some closing codes like closing database or network connection, taking backup etc.

Create a java file ShutdownHooksImpl.java in dev21century.threading package:

package dev21century.threading;

class ShutdownHooks implements Runnable

{

     public void run()

     {

           System.out.println("-- shutdown hookup started..");

           System.out.println("-- Application shutting down..");

           try{

                Thread.sleep(1000*5);

           }

           catch(Exception e)

           {

                System.out.println(e);

           }

     }

}

public class ShutdownHooksImpl {

 public static void main(String args[])

 {

     Runtime runTime = Runtime.getRuntime();

     ShutdownHooks hooks = new ShutdownHooks();

     //Register the shutdown hooks

     runTime.addShutdownHook(new Thread(hooks));

     int x =  100 / 0;

 }

}

Output:

In this program an exception occurred during program execution, even then the shutdown hookup thread got executed.