Hibernate errors with Singleton RuntimeManager and outer transaction in BPM Suite

Issue

Hibernate errors with Singleton RuntimeManager and outer transaction in BPM Suite

• An application embeds jBPM libraries. Sometimes I get the following errors

2018-05-15 13:36:36,410 WARN  [org.jbpm.shared.services.impl.TransactionalCommandService] (default task-87) Could not commit session: javax.persistence.PersistenceException: org.hibernate.HibernateException: Found shared references to a collection: org.jbpm.services.task.impl.model.TaskImpl.deadlines.endDeadlines
        at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1692)
        at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1602)
        at org.hibernate.jpa.internal.QueryImpl.getResultList(QueryImpl.java:492)
        at org.jbpm.shared.services.impl.JpaPersistenceContext.queryStringWithParameters(JpaPersistenceContext.java:190)
        at org.jbpm.shared.services.impl.JpaPersistenceContext.queryWithParametersInTransaction(JpaPersistenceContext.java:57)
        at org.jbpm.shared.services.impl.commands.QueryNameCommand.execute(QueryNameCommand.java:49)
        at org.jbpm.shared.services.impl.TransactionalCommandService.execute(TransactionalCommandService.java:71)
        at org.jbpm.kie.services.impl.RuntimeDataServiceImpl.getTasksByStatusByProcessInstanceId(RuntimeDataServiceImpl.java:880)
        at org.jbpm.services.cdi.impl.RuntimeDataServiceCDIImpl$Proxy$_$$_WeldClientProxy.getTasksByStatusByProcessInstanceId(Unknown Source)
        at com.example.MyService.findTaskIdsByProcessInstanceId(MyService.java:135)
        ...
Caused by: org.hibernate.HibernateException: Found shared references to a collection: org.jbpm.services.task.impl.model.TaskImpl.deadlines.endDeadlines
        at org.hibernate.engine.internal.Collections.processReachableCollection(Collections.java:183)
        at org.hibernate.event.internal.FlushVisitor.processCollection(FlushVisitor.java:46)
        at org.hibernate.event.internal.AbstractVisitor.processValue(AbstractVisitor.java:104)
        at org.hibernate.event.internal.AbstractVisitor.processValue(AbstractVisitor.java:65)
        at org.hibernate.event.internal.AbstractVisitor.processValues(AbstractVisitor.java:44)
        at org.hibernate.event.internal.AbstractVisitor.processComponent(AbstractVisitor.java:85)
        at org.hibernate.event.internal.AbstractVisitor.processValue(AbstractVisitor.java:110)
        at org.hibernate.event.internal.AbstractVisitor.processValue(AbstractVisitor.java:65)
        at org.hibernate.event.internal.AbstractVisitor.processEntityPropertyValues(AbstractVisitor.java:59)
        at org.hibernate.event.internal.DefaultFlushEntityEventListener.onFlushEntity(DefaultFlushEntityEventListener.java:155)
        at org.hibernate.event.internal.AbstractFlushingEventListener.flushEntities(AbstractFlushingEventListener.java:216)
        at org.hibernate.event.internal.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:85)
        at org.hibernate.event.internal.DefaultAutoFlushEventListener.onAutoFlush(DefaultAutoFlushEventListener.java:44)
        at org.hibernate.internal.SessionImpl.autoFlushIfRequired(SessionImpl.java:1251)
        at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1319)
        at org.hibernate.internal.QueryImpl.list(QueryImpl.java:87)
        at org.hibernate.jpa.internal.QueryImpl.list(QueryImpl.java:606)
        at org.hibernate.jpa.internal.QueryImpl.getResultList(QueryImpl.java:483)
        ... 276 more

2018-05-15 13:36:36,763 ERROR [org.hibernate.AssertionFailure] (default task-2) HHH000099: an assertion failure occured (this may indicate a bug in Hibernate, but is more likely due to unsafe use of the session): org.hibernate.AssertionFailure: possible nonthreadsafe access to session
2018-05-15 13:36:36,763 WARN  [org.jbpm.services.task.persistence.TaskTransactionInterceptor] (default task-2) Could not commit session: org.hibernate.AssertionFailure: possible nonthreadsafe access to session
    at org.hibernate.action.internal.EntityUpdateAction.execute(EntityUpdateAction.java:160)
    at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:582)
    at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:456)
    at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:337)
    at org.hibernate.event.internal.DefaultAutoFlushEventListener.onAutoFlush(DefaultAutoFlushEventListener.java:50)
    at org.hibernate.internal.SessionImpl.autoFlushIfRequired(SessionImpl.java:1251)
    at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1319)
    at org.hibernate.internal.QueryImpl.list(QueryImpl.java:87)
    at org.hibernate.jpa.internal.QueryImpl.list(QueryImpl.java:606)
    at org.hibernate.jpa.internal.QueryImpl.getResultList(QueryImpl.java:483)
    at org.jbpm.services.task.persistence.JPATaskPersistenceContext.queryStringWithParameters(JPATaskPersistenceContext.java:575)
    at org.jbpm.services.task.persistence.JPATaskPersistenceContext.queryWithParametersInTransaction(JPATaskPersistenceContext.java:398)
    at org.jbpm.services.task.impl.TaskDeadlinesServiceImpl.unschedule(TaskDeadlinesServiceImpl.java:137)
    at org.jbpm.services.task.commands.CancelDeadlineCommand.execute(CancelDeadlineCommand.java:71)
    at org.jbpm.services.task.commands.CancelDeadlineCommand.execute(CancelDeadlineCommand.java:33)
    at org.jbpm.services.task.commands.CompositeCommand.execute(CompositeCommand.java:145)
    at org.jbpm.services.task.commands.TaskCommandExecutorImpl$SelfExecutionCommandService.execute(TaskCommandExecutorImpl.java:65)
    at org.drools.core.command.impl.AbstractInterceptor.executeNext(AbstractInterceptor.java:41)
    at org.jbpm.services.task.persistence.TaskTransactionInterceptor.execute(TaskTransactionInterceptor.java:69)
    at org.drools.core.command.impl.AbstractInterceptor.executeNext(AbstractInterceptor.java:41)
    at org.drools.persistence.jta.TransactionLockInterceptor.execute(TransactionLockInterceptor.java:73)
    at org.drools.core.command.impl.AbstractInterceptor.executeNext(AbstractInterceptor.java:41)
    at org.drools.persistence.jpa.OptimisticLockRetryInterceptor.execute(OptimisticLockRetryInterceptor.java:82)
    at org.jbpm.services.task.commands.TaskCommandExecutorImpl.execute(TaskCommandExecutorImpl.java:40)
    at org.jbpm.services.task.impl.command.CommandBasedTaskService.complete(CommandBasedTaskService.java:177)
    at org.jbpm.runtime.manager.impl.task.SynchronizedTaskService.complete(SynchronizedTaskService.java:119)
    at org.jbpm.kie.services.impl.UserTaskServiceImpl.complete(UserTaskServiceImpl.java:189)
    at org.jbpm.services.cdi.impl.UserTaskServiceCDIImpl$Proxy$_$$_WeldClientProxy.complete(Unknown Source)
    at com.example.MyService.completeTask(MyService.java:272)