Java 获取@OneToMany的映射错误

我对Hibernate是新手，我对它有很大的问题。我有两门课：客户课和预订课。客户与预订是一对多关系

Client.java

  @Entity
  @Table (name="Clients")
  public class Clients  {   
  @Id
  @GeneratedValue 
  @Column(name="id_client")         
private int id_client;  

public Clients()    
{}
@OneToMany(mappedBy = "client")         
private Set<Reservations> reservation;

@Column(name="name")
private String name;

@Column(name="last_name")
private String lastName;

@Column(name="phoneNo")
private String phoneNo;

public Clients(String name, String lastName, String phone)
{
    this.name =name;
      this.lastName = lastName;
       this.phoneNo = phone;
}


 //  setters , getters

我的问题是：我犯了错误

无法创建sessionFactory object.org.hibernate.AnnotationException:使用@OneToMany或@ManyToMany以未映射的类为目标：model.java.hibernateApp.Clients.reservation[model.java.hibernateApp.Reservations]

尽管我看到了很多类似的话题，但我无法解决这个问题，谢谢你的帮助。

---

我从中学到：

请显示您的导入和persistence.xml或hibernate.cfg.xml。但是我的注释很好吗？因为我认为有一个错误。您应该检查类是否在persistence.xml或hibernate.cfg.xml中注册，并且@Entity注释是否来自包javax.persistence.Entity。此外，将类重命名为Client和Reservation。客户机的实例是一个客户机，因此没有理由调用类客户机。

 @Entity
 @Table (name="Reservations")

 public class Reservations  {

@Id
@GeneratedValue
@Column(name="id")
private int id_res;

    @ManyToOne
@JoinColumn( name = "id_client" )
private Clients client;

@Column(name="date_start")
private Calendar dateStart;

@Column(name="date_end")
private Calendar dateEnd;   

@Column(name="price")
private BigDecimal price;


public Reservations() {}

public Reservations(Clients client, Calendar dateStart, Calendar dateEnds)
{       
    this.client = client;       
    this.dateStart = dateStart;
    this.dateEnds = dateEnds;
}

   //  setters , getters