====== Scheduling Task ======
Scheduling Task include two steps. The First one is to add @EnableScheduling in the application, the second is the put @Scheduled on the top of the task/method. 

===== Put @EnableScheduling at the Application class =====

<code>
@SpringBootApplication
@EnableScheduling
public class Application {
   public static void main(String[] args) throws Exception {
       SpringApplication.run(Application.class);
   }
}
</code>
===== Put @Scheduled(cron = "* * * * * *") on the top of the task/method. =====
Put @Scheduled(cron = "* * * * * *") on the top of the task/method. The method must return void. The *s are representing Second, Minute, Hour, Day of Month, Month of Year, Day of Week, similar to cron job in Linux/Unix environment. eg: Run a task every second: 
<code>
   @Scheduled(cron = "*/1 * * * * *")
   void serviceMethod() {
       System.out.println("serviceMethod has been run");
   }
</code>
eg: Run a task every day on 23:59 
<code>
   @Scheduled(cron = "* 59 23 * * *")
   void serviceMethod() {
       System.out.println("serviceMethod has been run");
   }
</code>
There are other scheduled type can be used, such as fixedRate. eg: Execute the annotated method with a fixed period between invocations. Run a task every second. 
<code>
  @Scheduled(fixedRate=1000L)
   void serviceMethod() {
       System.out.println("serviceMethod has been run");
   }
</code>