Run Java EE CDI task with interval - wildfly

Question

I need to run a task with interval once my application (WAR) starts, I am using WildFly 21.
The task should be initialized at startup and perform some work at some interval.
the class is below
#ApplicationScoped
#ActivateRequestContext
public class TaskRunner {
#Resource private ManagedScheduledExecutorService scheduler;
#Inject private ScheduledFuture<?> TaskRunnerScheduler;
private boolean initialized = false;
private void init(#Observes #Initialized(ApplicationScoped.class) Object init) {
if (initialized) return;
initialized = true;
try {
// Execute at startup
TaskRunner = scheduler.schedule(this::runSchedule, getSchedule());
} catch (Throwable throwable) {
}
}
private void runSchedule() {
//do some work
}
private Trigger getSchedule() {
return new Trigger() {
#Override
public Date getNextRunTime(LastExecution lastExecutionInfo, Date taskScheduledTime) {
return Date.from(
ZonedDateTime.now().withSecond(0).withNano(0).plusHours("4").toInstant());
}
#Override
public boolean skipRun(LastExecution lastExecutionInfo, Date scheduledRunTime)
{return false;}};
}
}
When trying to deploy the application, I am getting the following error
ERROR [org.jboss.msc.service.fail] (MSC service thread 1-6) MSC000001: Failed to start service jboss.deployment.unit."task-web.war".WeldStartService: org.jboss.msc.service.StartException in service jboss.deployment.unit."task-web.war".WeldStartService: Failed to start service
at org.jboss.msc#1.4.12.Final//org.jboss.msc.service.ServiceControllerImpl$StartTask.execute(ServiceControllerImpl.java:1731)
at org.jboss.msc#1.4.12.Final//org.jboss.msc.service.ServiceControllerImpl$ControllerTask.run(ServiceControllerImpl.java:1559)
at org.jboss.threads#2.4.0.Final//org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35)
at org.jboss.threads#2.4.0.Final//org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:1990)
at org.jboss.threads#2.4.0.Final//org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1486)
at org.jboss.threads#2.4.0.Final//org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1377)
at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: org.jboss.weld.exceptions.DeploymentException: WELD-001408: Unsatisfied dependencies for type ScheduledFuture<?> with qualifiers #Default
at injection point [BackedAnnotatedField] #Inject private TaskRunner.TaskRunnerScheduler
at TaskRunner.TaskRunnerScheduler(TaskRunner.java:0)
at org.jboss.weld.core#3.1.5.Final//org.jboss.weld.bootstrap.Validator.validateInjectionPointForDeploymentProblems(Validator.java:378)
at org.jboss.weld.core#3.1.5.Final//org.jboss.weld.bootstrap.Validator.validateInjectionPoint(Validator.java:290)
at org.jboss.weld.core#3.1.5.Final//org.jboss.weld.bootstrap.Validator.validateGeneralBean(Validator.java:143)
at org.jboss.weld.core#3.1.5.Final//org.jboss.weld.bootstrap.Validator.validateRIBean(Validator.java:164)
at org.jboss.weld.core#3.1.5.Final//org.jboss.weld.bootstrap.Validator.validateBean(Validator.java:526)
at org.jboss.weld.core#3.1.5.Final//org.jboss.weld.bootstrap.ConcurrentValidator$1.doWork(ConcurrentValidator.java:64)
at org.jboss.weld.core#3.1.5.Final//org.jboss.weld.bootstrap.ConcurrentValidator$1.doWork(ConcurrentValidator.java:62)
at org.jboss.weld.core#3.1.5.Final//org.jboss.weld.executor.IterativeWorkerTaskFactory$1.call(IterativeWorkerTaskFactory.java:62)
at org.jboss.weld.core#3.1.5.Final//org.jboss.weld.executor.IterativeWorkerTaskFactory$1.call(IterativeWorkerTaskFactory.java:55)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.lang.Thread.run(Thread.java:834)
at org.jboss.threads#2.4.0.Final//org.jboss.threads.JBossThread.run(JBossThread.java:513)
Any ideas what is the cause of this error?

Answer 1

It looks like you want to run every 4 hours or so. Can I suggest a bit cleaner implementation?
#Startup
#Singleton
public class MyScheduler {
#PostConstruct
private void runAtStartup() {
// whatever makes sense here
}
#Schedule(hour = "*/4", persistent = false )
private void runSomething() {
// something here
}
}
This sets up an EJB to run at startup (#Startup), saying that there is only one instance of it (#Singleton). It then runs the runSomething() method every 4 hours. You can take a look at the Schedule Javadocs as there are many other ways to run this too. You may or may not need the #PostConstruct method if it previously only existed to setup the timer.
The persistent parameter tells Wildfly to remember when the last run was and, if restarted, continue to run on that schedule. If you don't care if your method runs again on restart then leave this false.
My only warning is that this mechanism doesn't handle overlaps. If you use this and a new schedule method is run before the last one finishes (in this example, 4 hours later) it can lead to errors in at least your log and the schedule not running the way you expect it to.

Answer 2

From your code snippet alone, simply remove the (unused) TaskRunnerScheduler field.

Answer 3

I found the issue, it was a typo in the following line
#Inject private ScheduledFuture<?> TaskRunnerScheduler;
the correct one is without the inject
private ScheduledFuture<?> TaskRunnerScheduler;