在JPA中使实体类行为只读

当我只映射了一个表时,我可以使用JPA获取值

现在,当我去映射相关的表时,我得到了一个错误

  Only one may be defined as writable, all others must be specified read-only.
  Mapping: org.eclipse.persistence.mappings.OneToOneMapping[userId1]

我正在使用[EclipseLink-0](Eclipse持久性服务-2.0.1.v20100213-r6600)

@OneToMany(cascade = CascadeType.ALL, mappedBy = "albumId")
private Collection<Images> imagesCollection;
@JoinColumn(name = "user_id", referencedColumnName = "User_ID")
@ManyToOne(optional = false)
private Roleuser userId;
@JoinColumn(name = "album_image", referencedColumnName = "image_id")
@ManyToOne
private Images albumImage;
@JoinColumn(name = "album_image", referencedColumnName = "image_id")
@ManyToOne
private Images albumImage1;
@JoinColumn(name = "user_id", referencedColumnName = "User_ID")
@ManyToOne(optional = false)
private Roleuser userId1;

要使字段为只读,我必须在代码中做哪些更改?