How to schedule EJB automatic Timers

Automatic timers are created by the EJB container when an enterprise bean that contains methods annotated with the @Schedule or @Schedules annotations is deployed. An enterprise bean can have multiple automatic timeout methods, unlike a programmatic timer, which allows only one method annotated with the @Timeout annotation in the enterprise bean class.

Automatic timers can be configured through annotations or through the ejb-jar.xml deployment descriptor.

Adding a @Schedule annotation on an enterprise bean marks that method as a timeout method according to the calendar schedule specified in the attributes of @Schedule. The @Schedule annotation has elements that correspond to the calendar expressions detailed in Creating Calendar-Based Timer Expressions and the persistent, info, and timezone elements.

Example: The following timeout method uses @Schedule to set a timer that will expire every Sunday at midnight:

package com.sample;
import javax.ejb.Stateless;
import java.util.Date;
import javax.ejb.Schedule;

public class AutomaticTimerBean
     @Schedule(dayOfWeek="Sun", hour="0")
     public void automaticTimer()
           System.out.println("\n\n\t Automatic Timer invoked at: "+new Date());

If you want a reference to the Timer attributes, check the following table:

Attribute Description Default Value Allowable Values and Examples
second One or more seconds within a minute 0 0 to 59. For example: second="30".
minute One or more minutes within an hour 0 0 to 59. For example: minute="15".
hour One or more hours within a day 0 0 to 23. For example: hour="13".
dayOfWeek One or more days within a week * 0 to 7 (both 0 and 7 refer to Sunday). For example: dayOfWeek="3".

SunMonTueWedThuFriSat. For example: dayOfWeek="Mon".

dayOfMonth One or more days within a month * 1 to 31. For example: dayOfMonth="15".

–7 to –1 (a negative number means the nth day or days before the end of the month). For example: dayOfMonth="–3".

Last. For example: dayOfMonth="Last".

[1st2nd3rd4th5thLast] [SunMonTueWedThuFriSat]. For example: dayOfMonth="2nd Fri".

month One or more months within a year * 1 to 12. For example: month="7".

JanFebMarAprMayJunJulAugSepOctNovDec. For example: month="July".

year A particular calendar year * A four–digit calendar year. For example: year="2011".