JPA没有认识到Serializable

Question

我有以下课程：

薄膜：

@Entity
@Table(name="film")
public class Film implements Serializable {

    @Id
    @Column(name="id")
    private String fbId;
    @Column(name="title")
    private String title;
    @Column(name="year")
    private int year;
    @Column(name="description")
    private String description;
    @ManyToMany
    @JoinTable(
        name="direction",
        joinColumns={@JoinColumn(name="person", referencedColumnName="id")},
        inverseJoinColumns={@JoinColumn(name="film", referencedColumnName="id")})
    private Collection<Person> directors;
    @ElementCollection
    @CollectionTable(name="genre", joinColumns=@JoinColumn(name="film"))
    @Column(name="id")
    private Collection<String> genres;
    @ElementCollection
    @CollectionTable(name="release", joinColumns=@JoinColumn(name="film"))
    @Column(name="id")
    private Collection<Release> releases;
    @ElementCollection
    @CollectionTable(name="trailers", joinColumns=@JoinColumn(name="film"))
    @Column(name="id")
    private Collection<URL> trailers;
    @OneToMany(mappedBy="film")
    @MapKey(name="character")
    private Map<String, Performance> performances;
}

性能：

@Entity
@Table(name="performance")
public class Performance implements Serializable {

    @Id
    @ManyToOne(fetch=FetchType.LAZY)
    @JoinColumn(name="id")
    private Film film;
    @Id
    @Column(name="film_character")
    private String character;
    @OneToOne(fetch=FetchType.LAZY)
    @JoinColumn(name="id")
    private Person actor;

}

人：

@Entity
@Table(name="person")
public class Person implements Serializable {

    @Id
    @Column(name="id")
    private String fbId;
    @Column(name="first_name")
    private String firstName;
    @Column(name="last_name")
    private String lastName;
    private Collection<Performance> performances;

}

推出：

@Entity
@Table(name="release")
public class Release implements Serializable {

    @Id
    @Column(name="film")
    private Film film;
    @Column(name="release_date")
    private Date releaseDate;
    @Column(name="medium")
    private String region;
    @Column(name="region")
    private String medium;

}

当我测试某些内容时，我收到以下错误，即使所有类都实现了Serializable

Caused by: org.hibernate.MappingException: Composite-id class must implement Serializable: sw.film.model.Performance