[JPA] org.hibernate.AnnotationException: Illegal attempt to map a non collection

Error Message

Invocation of init method failed; nested exception is org.hibernate.AnnotationException: Illegal attempt to map a non collection as a @OneToMany, @ManyToMany or @CollectionOfElements:



Solution

若是屬性的 annotation 有一方中是 many 的關係，則在 metamodel 中需寫成:

ListAttribute<Object1, Object2> attributes;