Why Lombok's @Data Annotation Can Break JPA Entities With Bidirectional Relationships

Using Lombok's @Data annotation on JPA entities can cause serious runtime issues, particularly when bidirectional relationships like @OneToMany and @ManyToOne are involved. The annotation auto-generates toString() and equals()/hashCode() methods that traverse entity fields, creating infinite recursive loops between parent and child entities. This can trigger a StackOverflowError, which may only surface under certain logging configurations — making the bug difficult to reproduce consistently across environments. The recommended fix is to apply @ToString.Exclude and @EqualsAndHashCode.Exclude on the relationship fields of the child entity to break the recursion. Additionally, when entities extend a base class, developers must explicitly configure how @EqualsAndHashCode handles inherited fields to avoid further hidden bugs.