Why You Should Avoid @Data on JPA Entities

When working with JPA entities, it is generally recommended to avoid using @Data annotations. This can be attributed to the generation of @ToString and @EqualsAndHashCode methods by Lombok. These annotations can lead to a recursivetoString() call and StackOverflowError when dealing with bidirectional relationships in entities.

For instance, consider an entity with a bidirectional relationship such as @OneToMany/@ManyToOne. If both entities use @Data, the toString() method generated by Lombok will be invoked recursively, causing a StackOverflowError. This occurs because the toString() method traverses all fields, leading to an endless cycle where parent calls child and child calls parent.

To resolve this issue, you can use the @ToString.Exclude and @EqualsAndHashCode.Exclude annotations on the child side of the relationship. These annotations prevent Lombok from including certain fields in the generated methods, thereby avoiding recursion.

Additionally, it is important to consider the impact of inheritance when using @Data annotations. If your entity extends a base class (like an AuditingEntity), you must explicitly decide how @EqualsAndHashCode should handle the parent class fields. Setting callSuper = false in @EqualsAndHashCode prevents the superclass's fields from participating in equality checks, which is particularly useful when dealing with technical or auditing fields such as createdAt, updatedAt, or deletedAt.

In conclusion, while @Data can be convenient, it is essential to understand how it generates methods and their potential impact on your application. Explicitly include only the necessary Lombok annotations to maintain control over the generated behavior and ensure a clean and efficient codebase.