ConcurrentModificationException in WildFlyJobXmlResolver -------------------------------------------------------- Key: WFLY-13162 URL: https://issues.redhat.com/browse/WFLY-13162 Project: WildFly Issue Type: Bug Components: Batch Affects Versions: 18.0.1.Final, 19.0.0.Beta3, 20.0.0.Beta1 Reporter: Hielke Hoeve Assignee: Cheng Fang Priority: Major Because of a thread unsafe construction in WildFlyJobXmlResolver I am experiencing ConcurrentModificationExceptions while starting my EAR every so often. This is because every EJB of the EAR is processed by WildFlyJobXmlResolver in paralel threads. Even if it has no jbatch dependency or dependency to a EJB which does. This is not reproducable for every startup as it depends on the performance of the host machine, number of ejbs in ear, number of threads and thread timing. I have created an example project representing our project setup with which I am able to reproduce the issue using a default wildfly build. This test project contains 1 EJB with jbatch, a number of plain EJBs, a WAR which uses the jbatch EJB and an EAR. See below for the exception stacktrace. I have made a small fix for this issue @ https://github.com/hielkehoeve/wildfly/commit/82047233621c3e5bdbd45333ca4.... The example test project can also be found there. {code:java} 08:32:30,164 ERROR [org.jboss.msc.service.fail] (MSC service thread 1-2) MSC000001: Failed to start service jboss.deployment.subunit."project.ear"."project-d.jar".POST_MODULE: org.jboss.msc.service.StartException in service jboss.deployment.subunit."project.ear"."project-d.jar".POST_MODULE: WFLYSRV0153: Failed to process phase POST_MODULE of subdeployment "project-d.jar" of deployment "project.ear" at org.jboss.as.server@10.0.0.Final//org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:183) at org.jboss.msc@1.4.11.Final//org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1739) at org.jboss.msc@1.4.11.Final//org.jboss.msc.service.ServiceControllerImpl$StartTask.execute(ServiceControllerImpl.java:1701) at org.jboss.msc@1.4.11.Final//org.jboss.msc.service.ServiceControllerImpl$ControllerTask.run(ServiceControllerImpl.java:1559) at org.jboss.threads@2.3.3.Final//org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35) at org.jboss.threads@2.3.3.Final//org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:1982) at org.jboss.threads@2.3.3.Final//org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1486) at org.jboss.threads@2.3.3.Final//org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1363) at java.base/java.lang.Thread.run(Thread.java:834) Caused by: java.util.ConcurrentModificationException at java.base/java.util.LinkedHashMap$LinkedHashIterator.nextNode(LinkedHashMap.java:719) at java.base/java.util.LinkedHashMap$LinkedKeyIterator.next(LinkedHashMap.java:741) at java.base/java.util.AbstractCollection.addAll(AbstractCollection.java:351) at org.wildfly.extension.batch.jberet@18.0.0.Final//org.wildfly.extension.batch.jberet.deployment.WildFlyJobXmlResolver.merge(WildFlyJobXmlResolver.java:261) at org.wildfly.extension.batch.jberet@18.0.0.Final//org.wildfly.extension.batch.jberet.deployment.WildFlyJobXmlResolver.forDeployment(WildFlyJobXmlResolver.java:127) at org.wildfly.extension.batch.jberet@18.0.0.Final//org.wildfly.extension.batch.jberet.deployment.WildFlyJobXmlResolver.forDeployment(WildFlyJobXmlResolver.java:130) at org.wildfly.extension.batch.jberet@18.0.0.Final//org.wildfly.extension.batch.jberet.deployment.WildFlyJobXmlResolver.forDeployment(WildFlyJobXmlResolver.java:130) at org.wildfly.extension.batch.jberet@18.0.0.Final//org.wildfly.extension.batch.jberet.deployment.WildFlyJobXmlResolver.forDeployment(WildFlyJobXmlResolver.java:130) at org.wildfly.extension.batch.jberet@18.0.0.Final//org.wildfly.extension.batch.jberet.deployment.WildFlyJobXmlResolver.forDeployment(WildFlyJobXmlResolver.java:130) at org.wildfly.extension.batch.jberet@18.0.0.Final//org.wildfly.extension.batch.jberet.deployment.BatchEnvironmentProcessor.deploy(BatchEnvironmentProcessor.java:78) at org.jboss.as.server@10.0.0.Final//org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:176) ... 8 more {code}