从类名转换为类时未找到类[+]

Question

我在该字段中有一个地图，它假定在MovieInfo之后继承的实体的密钥和相同的值。

@ElementCollection(fetch=FetchType.EAGER)
@CollectionTable(
        name="contributions_elements_to_update",
        joinColumns=@JoinColumn(name = "contribution_id")
)
@MapKeyColumn(name="new_element")
@Column(name = "old_element")
private Map<? extends MovieInfo, ? extends MovieInfo> elementsToUpdate;

编译时，编译器发出错误

Caused by: org.eclipse.persistence.exceptions.ValidationException: 
Exception Description: Class: [+] was not found while converting from class names to classes.
Internal Exception: java.lang.ClassNotFoundException: +

https://pastebin.com/QUpGa2PV