When i try to delete a process instance in Jbpm4, it throws the following error.
All i'm doing is calling the below statement on a newly created process instance.

executionService.deleteProcessInstance(id);

org.hibernate.exception.ConstraintViolationException: could not delete: [org.jbpm.pvm.internal.history.model.HistoryProcessInstanceImpl#
....
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Caused by: java.sql.SQLException: ORA-02292: integrity constraint (FK_HAI_HPI) violated - child record found