Determine when the application is about to exit : Runtime System « Development « Java Tutorial

1. Java Tutorial
2. Development
3. Runtime System

public class Main {
  public static void main(String[] argv) throws Exception {

    Runtime.getRuntime().addShutdownHook(new Thread() {
      public void run() {
        System.out.println("Do shutdown work ...");
      }
    });

  }
}