“多对一”属性类型不应是容器

Question

I have this class:

import org.springframework.security.core.userdetails.UserDetails;

@Entity
@Table(name="t_user")
@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonIgnoreProperties(ignoreUnknown = true)
@Data
public class User implements Serializable, UserDetails {

@Override
    public Collection<? extends GrantedAuthority> getAuthorities() {
        return null;
    }
..
}

but I have this compilation error:

'Many To One' attribute type should not be a container 

Answer 1

As Error says manyToOne should not be collection/list but should be single ojbect

@ManyToOne
Somthing somthing; // but not list

Answer 2

@ManyToOne should annotate a field not a collection. For collection fields the right annotation is @OneToMany .

So if you have

@ManyToOne
private List<Something> list;

that should be

@OneToMany
private List<Something> list;

Answer 3

1- @ManyToOne annotate a field,like that, in Hall classe:

@ManyToOne
private Cinema cinema;

2- @OneToMany annotate a collection, like that, in Cinema classe:

@OneToMany(mappedBy ="cinema")
private Collection<Hall> halls;

Answer 4

@OneToMany(cascade = CascadeType.ALL)
@JoinColumn(name = "user_id", referencedColumnName = "user_id")
private List<Address> address;

Since is a One-to-Many relationship, you must that, the other side is a list of something, ie List something