How to validate database schema programmatically in Hibernate 5 with Spring?

Question

This post is about validating DB schema with older versions of Hibernate. I try to update this code with Hibernate 5.

Here is a first naive implementation:

public boolean isSchemaValid() {

    // EntityManagerFactory is autowired by Spring
    SessionFactory sessionFactory =
            entityManagerFactory.unwrap(SessionFactory.class);

    ServiceRegistry serviceRegistry =
            sessionFactory.getSessionFactoryOptions().getServiceRegistry();

    try {
        new SchemaValidator().validate(
                new MetadataSources(serviceRegistry).buildMetadata(),
                serviceRegistry);
        return true;
    } catch (HibernateException ex) {
        return false;
    }
}

Without much surprise it doesn't work since it returns true even when the schema is not valid (the schema is different or does not exist). I guess this is because the Metadataobject passed to the new SchemaValidator.validate(...) method is not complete, e.g. does not contain the @Entitybean definitions. However I have a hard time finding out or to call this validate method properly.