Jackson #JsonIgnoreProperties seems not to work all the time - spring

Question

I mapped two entities to those following classes :
#Getter
#Entity
#Table(name = "users")
#JsonIdentityInfo(generator = PropertyGenerator.class,
property = "id")
#SequenceGenerator(name = "id-generator", sequenceName = "seq_users")
#EqualsAndHashCode(onlyExplicitlyIncluded = true, callSuper = false)
#NoArgsConstructor(access = PROTECTED)
#RequiredArgsConstructor
public class User extends IdentifiedById {
#Include
#NonNull
#Column(name = "email_address", unique = true)
private String emailAddress;
#Setter
#JsonIgnore
private String hash;
#Setter
private boolean admin;
#OneToMany(
mappedBy = "user",
orphanRemoval = true,
cascade = ALL
)
#JsonIgnoreProperties("user")
private Set<Cart> carts;
{
carts = new HashSet<>(0);
}
}
#Getter
#Entity
#Table(
name = "carts",
uniqueConstraints = #UniqueConstraint(
columnNames = {
"creation_time",
"user_id"
}
)
)
#JsonIdentityInfo(generator = PropertyGenerator.class,
property = "id")
#SequenceGenerator(
name = "id-generator",
sequenceName = "seq_carts"
)
#EqualsAndHashCode(
callSuper = false
)
#RequiredArgsConstructor
#NoArgsConstructor(access = PROTECTED)
public class Cart extends IdentifiedById {
#NonNull
#Column(name = "creation_time")
private LocalDateTime creationTime;
#NonNull
#ManyToOne(cascade = ALL)
#JoinColumn(
name = "user_id",
referencedColumnName = "id"
)
#JsonManagedReference
private User user;
#Exclude
#JsonProperty("productStoreQuantities")
#JsonSerialize(converter = AdditionConverter.class)
#OneToMany(mappedBy = "cart", orphanRemoval = true, cascade = ALL)
private Set<Addition> additions;
{
additions = new HashSet<>(0);
}
}
If I retrieve a user, its carts do not contain its reference, it is fine by me.
Now from a rest endpoint perspective I would like not to serialize users along with their carts if one requests multiple users like so :
**/api/users -> {"id":1, "emailAddress":"test#test.test", "admin": false}**
**/api/users/1 -> {"id":1, "emailAddress":"test#test.test", "admin": false, "carts": [...]}**
Thus, I created a wrapper class named Users containing a list of users annotated with #JsonValue and #JsonIgnoreProperties("carts") :
#RequiredArgsConstructor
public class Users implements Serializable, List<User> {
#Delegate
#JsonValue
#JsonIgnoreProperties("carts")
private final List<User> values;
}
I don't know why but carts keep being serialized, I heard that #JsonIgnoreProperties does not work on collections and arrays but it does in my first case.

Answer 1

You should use JsonIgnoreProperties in a class level.
This is well explained in this post
https://www.baeldung.com/jackson-ignore-properties-on-serialization