Skip to main content
Redhat Developers  Logo
  • Products

    Featured

    • Red Hat Enterprise Linux
      Red Hat Enterprise Linux Icon
    • Red Hat OpenShift AI
      Red Hat OpenShift AI
    • Red Hat Enterprise Linux AI
      Linux icon inside of a brain
    • Image mode for Red Hat Enterprise Linux
      RHEL image mode
    • Red Hat OpenShift
      Openshift icon
    • Red Hat Ansible Automation Platform
      Ansible icon
    • Red Hat Developer Hub
      Developer Hub
    • View All Red Hat Products
    • Linux

      • Red Hat Enterprise Linux
      • Image mode for Red Hat Enterprise Linux
      • Red Hat Universal Base Images (UBI)
    • Java runtimes & frameworks

      • JBoss Enterprise Application Platform
      • Red Hat build of OpenJDK
    • Kubernetes

      • Red Hat OpenShift
      • Microsoft Azure Red Hat OpenShift
      • Red Hat OpenShift Virtualization
      • Red Hat OpenShift Lightspeed
    • Integration & App Connectivity

      • Red Hat Build of Apache Camel
      • Red Hat Service Interconnect
      • Red Hat Connectivity Link
    • AI/ML

      • Red Hat OpenShift AI
      • Red Hat Enterprise Linux AI
    • Automation

      • Red Hat Ansible Automation Platform
      • Red Hat Ansible Lightspeed
    • Developer tools

      • Red Hat Trusted Software Supply Chain
      • Podman Desktop
      • Red Hat OpenShift Dev Spaces
    • Developer Sandbox

      Developer Sandbox
      Try Red Hat products and technologies without setup or configuration fees for 30 days with this shared Openshift and Kubernetes cluster.
    • Try at no cost
  • Technologies

    Featured

    • AI/ML
      AI/ML Icon
    • Linux
      Linux Icon
    • Kubernetes
      Cloud icon
    • Automation
      Automation Icon showing arrows moving in a circle around a gear
    • View All Technologies
    • Programming Languages & Frameworks

      • Java
      • Python
      • JavaScript
    • System Design & Architecture

      • Red Hat architecture and design patterns
      • Microservices
      • Event-Driven Architecture
      • Databases
    • Developer Productivity

      • Developer productivity
      • Developer Tools
      • GitOps
    • Secure Development & Architectures

      • Security
      • Secure coding
    • Platform Engineering

      • DevOps
      • DevSecOps
      • Ansible automation for applications and services
    • Automated Data Processing

      • AI/ML
      • Data Science
      • Apache Kafka on Kubernetes
      • View All Technologies
    • Start exploring in the Developer Sandbox for free

      sandbox graphic
      Try Red Hat's products and technologies without setup or configuration.
    • Try at no cost
  • Learn

    Featured

    • Kubernetes & Cloud Native
      Openshift icon
    • Linux
      Rhel icon
    • Automation
      Ansible cloud icon
    • Java
      Java icon
    • AI/ML
      AI/ML Icon
    • View All Learning Resources

    E-Books

    • GitOps Cookbook
    • Podman in Action
    • Kubernetes Operators
    • The Path to GitOps
    • View All E-books

    Cheat Sheets

    • Linux Commands
    • Bash Commands
    • Git
    • systemd Commands
    • View All Cheat Sheets

    Documentation

    • API Catalog
    • Product Documentation
    • Legacy Documentation
    • Red Hat Learning

      Learning image
      Boost your technical skills to expert-level with the help of interactive lessons offered by various Red Hat Learning programs.
    • Explore Red Hat Learning
  • Developer Sandbox

    Developer Sandbox

    • Access Red Hat’s products and technologies without setup or configuration, and start developing quicker than ever before with our new, no-cost sandbox environments.
    • Explore Developer Sandbox

    Featured Developer Sandbox activities

    • Get started with your Developer Sandbox
    • OpenShift virtualization and application modernization using the Developer Sandbox
    • Explore all Developer Sandbox activities

    Ready to start developing apps?

    • Try at no cost
  • Blog
  • Events
  • Videos

Jakarta EE: Creating an Enterprise JavaBeans timer

December 13, 2019
Rhuan Rocha
Related topics:
Java
Related products:
Red Hat build of OpenJDK

Share:

    Enterprise JavaBeans (EJB) has many interesting and useful features, some of which I will be highlighting in this and upcoming articles. In this article, I'll show you how to create an EJB timer programmatically and with annotation. Let's go!

    The EJB timer feature allows us to schedule tasks to be executed according a calendar configuration. It is very useful because we can execute scheduled tasks using the power of Jakarta context. When we run tasks based on a timer, we need to answer some questions about concurrency, which node the task was scheduled on (in case of an application in a cluster), what is the action if the task does not execute, and others. When we use the EJB timer we can delegate many of these concerns to Jakarta context and care more about business logic. It is interesting, isn't it?

    Creating an EJB timer programmatically

    We can schedule an EJB timer to runs according to a business logic using a programmatic approach. This method can be used when we want a dynamic behavior, according to the parameter values passed to the process. Let's look at an example of an EJB timer:

    import javax.annotation.Resource;
    import javax.ejb.SessionContext;
    import javax.ejb.Stateless;
    import javax.ejb.Timeout;
    import java.util.logging.Logger;
    
    @Stateless
    public class MyTimer {
    
        private Logger logger = Logger.getLogger(MyTimer.class.getName());
        @Resource
        private SessionContext context;
    
        public void initTimer(String message){
            context.getTimerService().createTimer(10000, message);
        }
    
        @Timeout
        public void execute(){
            logger.info("Starting");
    
            context.getTimerService().getAllTimers().stream().forEach(timer -> logger.info(String.valueOf(timer.getInfo())));
            
    
            logger.info("Ending");
        }    
    }
    
    

    To schedule this EJB timer, call this method:

    @Inject
    private MyTimer myTimer;
    ....
    myTimer.initTimer(message);

    After passing 10000 milliseconds, the method annotated with @Timeout will be called.

    Scheduling an EJB timer using annotation

    We can also create an EJB timer that is automatically scheduled to run according to an annotation configuration. Look at this example:

    @Singleton
    public class MyTimerAutomatic {
    
        private Logger logger = Logger.getLogger(MyTimerAutomatic.class.getName());
    
        @Schedule(hour = "*", minute = "*",second = "0,10,20,30,40,50",persistent = false)
        public void execute(){
    
            logger.info("Automatic timer executing");
    
        }
    }
    

    As you can see, to configure an automatic EJB timer schedule, you can annotate the method using @Schedule and configure the calendar attributes. For example:

    @Schedule(hour = "*", minute = "*",second = "0,10,20,30,40,50",persistent = false)

    As you can see, the method execute is configured to be called every 10 seconds. You can configure whether the timer is persistent as well.

    Conclusion

    EJB timer is a good EJB feature that is helpful in solving many problems. Using the EJB timer feature, we can schedule tasks to be executed, thereby delegating some responsibilities to Jakarta context to solve for us. Furthermore, we can create persistent timers, control the concurrent execution, and work with it in a clustered environment.  If you want to see the complete example, visit this repository on GitHub.

    Last updated: September 27, 2024

    Recent Posts

    • GuideLLM: Evaluate LLM deployments for real-world inference

    • Unleashing multimodal magic with RamaLama

    • Integrate Red Hat AI Inference Server & LangChain in agentic workflows

    • Streamline multi-cloud operations with Ansible and ServiceNow

    • Automate dynamic application security testing with RapiDAST

    Red Hat Developers logo LinkedIn YouTube Twitter Facebook

    Products

    • Red Hat Enterprise Linux
    • Red Hat OpenShift
    • Red Hat Ansible Automation Platform

    Build

    • Developer Sandbox
    • Developer Tools
    • Interactive Tutorials
    • API Catalog

    Quicklinks

    • Learning Resources
    • E-books
    • Cheat Sheets
    • Blog
    • Events
    • Newsletter

    Communicate

    • About us
    • Contact sales
    • Find a partner
    • Report a website issue
    • Site Status Dashboard
    • Report a security problem

    RED HAT DEVELOPER

    Build here. Go anywhere.

    We serve the builders. The problem solvers who create careers with code.

    Join us if you’re a developer, software engineer, web designer, front-end designer, UX designer, computer scientist, architect, tester, product manager, project manager or team lead.

    Sign me up

    Red Hat legal and privacy links

    • About Red Hat
    • Jobs
    • Events
    • Locations
    • Contact Red Hat
    • Red Hat Blog
    • Inclusion at Red Hat
    • Cool Stuff Store
    • Red Hat Summit

    Red Hat legal and privacy links

    • Privacy statement
    • Terms of use
    • All policies and guidelines
    • Digital accessibility

    Report a website issue