NullPointerException on taskService.getTasksAssignedAsPotentialOwnerByStatusByGroup() in BRMS 5.3

Issue

• When a request is sent from the client to the server to get the user's tasks with a user id and empty group id list as parameters, there is an "unexpected end of subtree" exception being thrown. The server generate a RuntimeException and sends that back to the client, therefore the original message and its content are lost and the client doesn't know what happened on the server.

server side:

17:00:43,624 ERROR [TaskServerHandler] Operation failed
java.lang.RuntimeException: Operation failed
    at org.jbpm.task.service.persistence.TaskPersistenceManager.queryWithParametersInTransaction(TaskPersistenceManager.java:302)
    at org.jbpm.task.service.persistence.TaskPersistenceManager.queryWithParametersInTransaction(TaskPersistenceManager.java:309)
    at org.jbpm.task.service.TaskServiceSession.getTasksAssignedAsPotentialOwnerByStatusByGroup(TaskServiceSession.java:1048)
    at org.jbpm.task.service.TaskServerHandler.messageReceived(TaskServerHandler.java:354)
    at org.jbpm.task.service.hornetq.HornetQTaskServerHandler.messageReceived(HornetQTaskServerHandler.java:44)
    at org.jbpm.task.service.hornetq.BaseHornetQTaskServer.run(BaseHornetQTaskServer.java:104)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.IllegalArgumentException: org.hibernate.hql.ast.QuerySyntaxException: unexpected end of subtree [select new org.jbpm.task.query.TaskSummary( t.id, t.taskData.processInstanceId, name.text, subject.text, description.text, t.taskData.status, t.priority, t.taskData.skipable, actualOwner, createdBy, t.taskData.createdOn, t.taskData.activationTime, t.taskData.expirationTime, t.taskData.processId, t.taskData.processSessionId) from org.jbpm.task.Task t left join t.taskData.createdBy as createdBy left join t.taskData.actualOwner as actualOwner left join t.subjects as subject left join t.descriptions as description left join t.names as name, org.jbpm.task.OrganizationalEntity potentialOwners where t.archived = 0 and ( potentialOwners.id = :userId or potentialOwners.id in () ) and potentialOwners in elements ( t.peopleAssignments.potentialOwners ) and ( name.language = :language or t.names.size = 0 ) and ( subject.language = :language or t.subjects.size = 0 ) and ( description.language = :language or t.descriptions.size = 0 ) and t.taskData.status in (:status0_, :status1_) and t.taskData.expirationTime is null]
    at org.hibernate.ejb.AbstractEntityManagerImpl.throwPersistenceException(AbstractEntityManagerImpl.java:603)
    at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:103)
    at org.jbpm.task.service.persistence.TaskPersistenceManager.queryWithParameters(TaskPersistenceManager.java:344)
    at org.jbpm.task.service.persistence.TaskPersistenceManager.queryWithParametersInTransaction(TaskPersistenceManager.java:287)
    ... 6 more
Caused by: org.hibernate.hql.ast.QuerySyntaxException: unexpected end of subtree [select new org.jbpm.task.query.TaskSummary( t.id, t.taskData.processInstanceId, name.text, subject.text, description.text, t.taskData.status, t.priority, t.taskData.skipable, actualOwner, createdBy, t.taskData.createdOn, t.taskData.activationTime, t.taskData.expirationTime, t.taskData.processId, t.taskData.processSessionId) from org.jbpm.task.Task t left join t.taskData.createdBy as createdBy left join t.taskData.actualOwner as actualOwner left join t.subjects as subject left join t.descriptions as description left join t.names as name, org.jbpm.task.OrganizationalEntity potentialOwners where t.archived = 0 and ( potentialOwners.id = :userId or potentialOwners.id in () ) and potentialOwners in elements ( t.peopleAssignments.potentialOwners ) and ( name.language = :language or t.names.size = 0 ) and ( subject.language = :language or t.subjects.size = 0 ) and ( description.language = :language or t.descriptions.size = 0 ) and t.taskData.status in (:status0_, :status1_) and t.taskData.expirationTime is null]
    at org.hibernate.hql.ast.QuerySyntaxException.convert(QuerySyntaxException.java:55)
    at org.hibernate.hql.ast.QuerySyntaxException.convert(QuerySyntaxException.java:48)
    at org.hibernate.hql.ast.ErrorCounter.throwQueryException(ErrorCounter.java:83)
    at org.hibernate.hql.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:262)
    at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:186)
    at org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:137)
    at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:101)
    at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:80)
    at org.hibernate.engine.query.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:124)
    at org.hibernate.impl.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:156)
    at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1184)
    at org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)
    at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:94)
    ... 8 more

client side:

24/02 17:01:52,905[Thread-1] ERROR service.hornetq.HornetQTaskClientConnector.run  - Client Exception with class class org.jbpm.task.service.hornetq.HornetQTaskClientConnector$1 using port 5153
java.lang.NullPointerException
    at org.jbpm.task.service.TaskClientHandler.messageReceived(TaskClientHandler.java:62)
    at org.jbpm.task.service.hornetq.HornetQTaskClientHandler.messageReceived(HornetQTaskClientHandler.java:56)
    at org.jbpm.task.service.hornetq.HornetQTaskClientConnector$1.run(HornetQTaskClientConnector.java:122)
    at java.lang.Thread.run(Thread.java:662)
Exception in thread "main" java.lang.RuntimeException: Timeout : unable to retrieve results
    at org.jbpm.task.service.responsehandlers.BlockingTaskSummaryResponseHandler.getResults(BlockingTaskSummaryResponseHandler.java:41)
    at org.jbpm.task.service.AsyncTaskServiceWrapper.getTasksAssignedAsPotentialOwnerByStatusByGroup(AsyncTaskServiceWrapper.java:756)
    at com.sample.ProcessMainHQJohn.main(ProcessMainHQJohn.java:44)