ClassCastException: org.hibernate.internal.SessionImpl cannot be cast to org.hibernate.ejb.HibernateEntityManager in Hibernate

Issue

• Attempting to unwrap the Hibernate EntityManager instance in order to obtain the encapsulated legacy interface object (the Hibernate Session):

  org.hibernate.Session session = entityManager.unwrap(org.hibernate.ejb.HibernateEntityManager.class).getSession();
  

• Encountering an exception:

  java.lang.ClassCastException: org.hibernate.internal.SessionImpl cannot be cast to org.hibernate.ejb.HibernateEntityManager