Java Shutdown Hooks

 A shut down hook is simply a Thread that is registered with the JVM and run just before the JVM shuts down.


Example code taken from the below mentioned link:




package example;public class ShutdownHook {

  /**
   * @param args
   */
  public static void main(String[] args) {
    Hook hook = new Hook();
    System.out.println( "Running Main Application..." );
    Runtime.getRuntime().addShutdownHook( hook );
    System.out.println( "Exiting." );
  }

  
  private static class Hook extends Thread {
    public void run() {
      System.out.println( "Running Clean Up..." );
    }
  }
}


http://www.crazysquirrel.com/computing/java/basics/java-shutdown-hooks.jspx

http://stackoverflow.com/questions/2921945/useful-example-of-a-shutdown-hook-in-java