Why can @Data be risky on JPA entity classes?

@Data bundles @EqualsAndHashCode and @ToString across every field, which interacts poorly with several JPA/Hibernate specifics: lazy-loaded associations can trigger unwanted database queries the moment toString() or equals() touches them, and including a mutable, database-generated id field in equals/hashCode can break collection behavior for entities that are added to a Set before being persisted (when the id is still null) and then persisted afterward (when it gets a real value).

@Entity
@Data   //  risky: consider a more targeted set of annotations instead
public class Order {
    @Id
    private Long id;

    @OneToMany
    private List<OrderItem> items;   //  lazy loading + toString/equals = trouble
}

A more deliberate approach on entities is usually: exclude lazy associations from @ToString/@EqualsAndHashCode, and base equality on a stable business key rather than the mutable, sometimes-null database id, rather than reaching for the all-in-one @Data bundle by default.

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