Duplicate class name in the persistence.xml file located in business central war (BPMS 6.4) file.
<!-- task service -->
<class>org.jbpm.services.task.impl.model.AttachmentImpl</class>
<class>org.jbpm.services.task.impl.model.ContentImpl</class>
<class>org.jbpm.services.task.impl.model.BooleanExpressionImpl</class>
<class>org.jbpm.services.task.impl.model.CommentImpl</class>
<class>org.jbpm.services.task.impl.model.DeadlineImpl</class>
- <class>org.jbpm.services.task.impl.model.CommentImpl</class>-
<class>org.jbpm.services.task.impl.model.DeadlineImpl</class>
<class>org.jbpm.services.task.impl.model.DelegationImpl</class>
<class>org.jbpm.services.task.impl.model.EscalationImpl</class>
<class>org.jbpm.services.task.impl.model.GroupImpl</class>
<class>org.jbpm.services.task.impl.model.I18NTextImpl</class>
<class>org.jbpm.services.task.impl.model.NotificationImpl</class>