Issue

As a way to asynchronously call our EJBs from inside a process, I want to use the executor.
In order to achieve that, following KCS was followed.

WorkItem named "async" (automatically mapped to org.jbpm.executor.impl.wih.AsyncWorkItemHandler) was created and placed in a process containing only that task.
If no command class is given, this WIH uses org.jbpm.executor.commands.PrintOutCommand. If 'autocomplete' is not set, it registers org.jbpm.executor.impl.wih.AsyncWorkItemHandlerCmdCallback.

The problem is that an error is raised at AsyncWorkItemHandlerCmdCallback.java:62.
It is caused by an InvocationTargetException at KnowledgeStoreServiceImpl.java:143, itself caused by a NullPointerException at TransactionSynchronizationRegistryWrapper.java:69. The full stacktrace look like this:

2017-09-19 16:21:12,071 WARN  [org.drools.persistence.TransactionSynchronizationRegistryHelper] (EJB default - 3) Unable to put resource org.kie.api.persistence.jpa.AppScopedEntityManager value org.hibernate.jpa.internal.EntityManagerImpl@6f8ad042 due to No transaction is running
2017-09-19 16:21:12,071 WARN  [org.drools.persistence.SingleSessionCommandService] (EJB default - 3) Could not commit session: java.lang.NullPointerException
    at java.util.concurrent.ConcurrentHashMap.get(ConcurrentHashMap.java:936)
    at org.jboss.as.txn.service.internal.tsr.TransactionSynchronizationRegistryWrapper.registerInterposedSynchronization(TransactionSynchronizationRegistryWrapper.java:69)
    at org.drools.persistence.TransactionSynchronizationRegistryHelper.registerTransactionSynchronization(TransactionSynchronizationRegistryHelper.java:29)
    at org.jbpm.persistence.jta.ContainerManagedTransactionManager.registerTransactionSynchronization(ContainerManagedTransactionManager.java:75)
    at org.drools.persistence.TransactionManagerHelper.registerTransactionSyncInContainer(TransactionManagerHelper.java:31)
    at org.drools.persistence.SingleSessionCommandService.registerRollbackSync(SingleSessionCommandService.java:462)
    at org.drools.persistence.SingleSessionCommandService.<init>(SingleSessionCommandService.java:188)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at org.drools.persistence.jpa.KnowledgeStoreServiceImpl.buildCommandService(KnowledgeStoreServiceImpl.java:143)
    at org.drools.persistence.jpa.KnowledgeStoreServiceImpl.loadKieSession(KnowledgeStoreServiceImpl.java:111)
    at org.drools.persistence.jpa.KnowledgeStoreServiceImpl.loadKieSession(KnowledgeStoreServiceImpl.java:39)
    at org.kie.internal.persistence.jpa.JPAKnowledgeService.loadStatefulKnowledgeSession(JPAKnowledgeService.java:144)
    at org.jbpm.runtime.manager.impl.factory.JPASessionFactory.findKieSessionById(JPASessionFactory.java:53)
    at org.jbpm.runtime.manager.impl.PerProcessInstanceRuntimeManager$PerProcessInstanceInitializer.initKieSession(PerProcessInstanceRuntimeManager.java:560)
    at org.jbpm.runtime.manager.impl.RuntimeEngineImpl.getKieSession(RuntimeEngineImpl.java:72)
    at org.jbpm.executor.impl.wih.AsyncWorkItemHandlerCmdCallback.onCommandDone(AsyncWorkItemHandlerCmdCallback.java:62)
    at org.jbpm.executor.impl.AbstractAvailableJobsExecutor.executeGivenJob(AbstractAvailableJobsExecutor.java:128)
    at org.jbpm.executor.impl.AvailableJobsExecutor.executeJob(AvailableJobsExecutor.java:38)
    at org.jbpm.executor.ejb.impl.AvailableJobsExecutorEJBImpl.executeJob(AvailableJobsExecutorEJBImpl.java:55)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.jboss.as.ee.component.ManagedReferenceMethodInterceptor.processInvocation(ManagedReferenceMethodInterceptor.java:52)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.invocation.InterceptorContext$Invocation.proceed(InterceptorContext.java:437)
    at org.jboss.as.weld.ejb.Jsr299BindingsInterceptor.doMethodInterception(Jsr299BindingsInterceptor.java:82)
    at org.jboss.as.weld.ejb.Jsr299BindingsInterceptor.processInvocation(Jsr299BindingsInterceptor.java:93)
    at org.jboss.as.ee.component.interceptors.UserInterceptorFactory$1.processInvocation(UserInterceptorFactory.java:63)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ejb3.component.invocationmetrics.ExecutionTimeInterceptor.processInvocation(ExecutionTimeInterceptor.java:43)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.jpa.interceptor.SBInvocationInterceptor.processInvocation(SBInvocationInterceptor.java:47)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ejb3.tx.EjbBMTInterceptor.handleInvocation(EjbBMTInterceptor.java:103)
    at org.jboss.as.ejb3.tx.BMTInterceptor.processInvocation(BMTInterceptor.java:58)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ee.concurrent.ConcurrentContextInterceptor.processInvocation(ConcurrentContextInterceptor.java:45)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.invocation.InitialInterceptor.processInvocation(InitialInterceptor.java:21)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61)
    at org.jboss.as.ee.component.interceptors.ComponentDispatcherInterceptor.processInvocation(ComponentDispatcherInterceptor.java:52)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ejb3.component.pool.PooledInstanceInterceptor.processInvocation(PooledInstanceInterceptor.java:51)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.invocation.InterceptorContext$Invocation.proceed(InterceptorContext.java:437)
    at org.jboss.weld.ejb.AbstractEJBRequestScopeActivationInterceptor.aroundInvoke(AbstractEJBRequestScopeActivationInterceptor.java:73)
    at org.jboss.as.weld.ejb.EjbRequestScopeActivationInterceptor.processInvocation(EjbRequestScopeActivationInterceptor.java:83)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ejb3.component.interceptors.CurrentInvocationContextInterceptor.processInvocation(CurrentInvocationContextInterceptor.java:41)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ejb3.component.invocationmetrics.WaitTimeInterceptor.processInvocation(WaitTimeInterceptor.java:43)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ejb3.security.SecurityContextInterceptor.processInvocation(SecurityContextInterceptor.java:100)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ejb3.deployment.processors.StartupAwaitInterceptor.processInvocation(StartupAwaitInterceptor.java:22)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ejb3.component.interceptors.ShutDownInterceptorFactory$1.processInvocation(ShutDownInterceptorFactory.java:64)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ejb3.component.interceptors.LoggingInterceptor.processInvocation(LoggingInterceptor.java:66)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ee.component.NamespaceContextInterceptor.processInvocation(NamespaceContextInterceptor.java:50)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ejb3.component.interceptors.AdditionalSetupInterceptor.processInvocation(AdditionalSetupInterceptor.java:54)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.invocation.ContextClassLoaderInterceptor.processInvocation(ContextClassLoaderInterceptor.java:64)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.invocation.InterceptorContext.run(InterceptorContext.java:356)
    at org.wildfly.security.manager.WildFlySecurityManager.doChecked(WildFlySecurityManager.java:632)
    at org.jboss.invocation.AccessCheckingInterceptor.processInvocation(AccessCheckingInterceptor.java:61)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.invocation.InterceptorContext.run(InterceptorContext.java:356)
    at org.jboss.invocation.PrivilegedWithCombinerInterceptor.processInvocation(PrivilegedWithCombinerInterceptor.java:80)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61)
    at org.jboss.as.ee.component.ViewService$View.invoke(ViewService.java:198)
    at org.jboss.as.ee.component.ViewDescription$1.processInvocation(ViewDescription.java:185)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ejb3.component.interceptors.LogDiagnosticContextRecoveryInterceptor.processInvocation(LogDiagnosticContextRecoveryInterceptor.java:82)
    at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
    at org.jboss.as.ejb3.component.interceptors.AsyncFutureInterceptorFactory$1$2.runInvocation(AsyncFutureInterceptorFactory.java:104)
    at org.jboss.as.ejb3.component.interceptors.AsyncInvocationTask.run(AsyncInvocationTask.java:74)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:748)
    at org.jboss.threads.JBossThread.run(JBossThread.java:320)

This happens only when org.jbpm.persistence.jta.ContainerManagedTransactionManager is used, which was configured due to another error in the CMT environment as per this KCS.
If default TransactionManager is used, then there is no error