How to prove JPA Enity must not be final class with Hibernate 5

Question

JSR 338: Java^TM Persistence API 2.1 Specification > 2.1 The Entity Class specifies:

The entity class must not be final. No methods or persistent instance variables of the entity class may be final.

So I tried with Hibernate 5.2.18.Final to prove it by setting an entity class as final:

@EqualsAndHashCode
@Getter
@Setter
@Entity
public final class City {
    @Id
    @SequenceGenerator(name="city_sequence", sequenceName="city_seq", initialValue=0, allocationSize=25)
    @GeneratedValue(strategy=SEQUENCE, generator="city_sequence")
    private int id;
    @Column(length=20, nullable=false)
    private String city;
    @ManyToOne(fetch = FetchType.LAZY)
    private Province province;
}

However, the result is out of my expectation: the corresponding table can be generated and new instance of City can be persisted to the database, meaning my code proves that entity class can be final

Question: Is there any better way to prove the entity class must not be final? Isn't it a hard-and-fast rule as it is in the specification?