Lombok.hashCode issue with "java.lang.StackOverflowError: null"

Question

I have two tables has one to one relationship as below:

@Entity @Data @NoArgsConstructor @AllArgsConstructor public class Book { @Id @GeneratedValue(strategy = GenerationType.TABLE) private int id; private String name; @OneToOne(cascade = CascadeType.ALL) @JoinColumn(name = "book_dtail_id") private BookDetail bookDetail; } @Entity @Table(name = "book_detail") @Data @NoArgsConstructor @AllArgsConstructor public class BookDetail { @Id @GeneratedValue(strategy = GenerationType.TABLE) private Integer id; @Column(name = "number_of_pages") private Integer numberOfPages; @OneToOne(mappedBy = "bookDetail") private Book book; }

I used a Form to input data as below

@Data @NoArgsConstructor @AllArgsConstructor public class BookForm { Book book; BookDetail bookDetail; }

The controller looks like this:

String handleNewBook(Model model){ Book book = new Book(); BookDetail bookDetail = new BookDetail(); BookForm bookForm = new BookForm(book, bookDetail); model.addAttribute("bookForm", bookForm); return "index"; } String handleSaveBookCreate(BookForm bookForm, Model model){ bookForm.getBook().setBookDetail(bookForm.getBookDetail()); bookForm.getBookDetail().setBook(bookForm.getBook()); bookService.save(bookForm.getBook())); return "index"; }

Last is my form as below:

<form role="form" action="#" th:object="${bookForm}" th:action="@{/book}" method="POST"> <input type="text" th:field="*{book.name}"/> <input type="text" th:filed="*{bookDetail} == null ? '' : *{bookDetail.numberOfPages}" placeholder="Enter Book Page Numbers"/> <button type="submit">Submit</button> </form>

everything seems no problems, but when I "bookService.save(bookForm.getBook()));" is executed, I got error as below

java.lang.StackOverflowError: null, at com.zangland.study.jpa.entity.BookDetail.hashCode(BookDetail.java:17) ~[classes/:na] at com.zangland.study.jpa.entity.Book.hashCode(Book.java:16) ~[classes/:na] at com.zangland.study.jpa.entity.BookDetail.hashCode(BookDetail.java:17) ~[classes/:na] at com.zangland.study.jpa.entity.Book.hashCode(Book.java:16) ~[classes/:na]

repeat the same as above about 100 lines.... do this mean that I can't use Lombok.hashCode?

Saved Book: '32768','Spring JPA','32768' Saved BookDetail: '32768','1157'

M-Razavi · Accepted Answer · 2021-01-15 15:12:08Z

92

You have a circular dependency between book and bookdetails. You probably need to exclude book from BookDetail or bookDetail from Book.

You can add @EqualsAndHashCode(exclude="book"). For more information, see the EqualsAndHashCode documentation.

edited Jan 15, 2021 at 15:12

M-Razavi

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answered Jan 25, 2016 at 8:44

Roel Spilker

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2 Comments

mikezang Over a year ago

How can I do it, it is Lombok features?

Roel Spilker Over a year ago

You can add @EqualsAndHashCode(exclude="book"). For more information, see the EqualsAndHashCode documentation.

Mohhamed Nabil · Accepted Answer · 2020-12-01 14:28:00Z

21

lambok resulted to a circular dependency

reason: the toString() method

solution: replace one of your models to

@Getter @Setter public class BookDetail

instead of

@Data public class BookDetail

answered Dec 1, 2020 at 14:28

Mohhamed Nabil

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4 Comments

jared Over a year ago

Or use @ToString(exclude = "book")

Andrey M. Stepanov Over a year ago

why it will help?

TrollBearPig Over a year ago

Thank you!!! This fixed my issue which was similar to OP

ashwani kumar Over a year ago

@Jared, having the object excluded from ToString worked for me. Thank you!

Kevin KOUOMEU · Accepted Answer · 2024-06-28 09:25:37Z

A solution that worked for me, is the add this annotation to your concerned entity

@EqualsAndHashCode(onlyExplicitlyIncluded = true) public class YourEntityName

If you want lombok to generate equals() and Hashcode() for a specific variable, you can mark them with @EqualsAndHashCode.Include, otherwise just mark your entity with the annotation I specified up there, and it will solve your problem.

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