JPA Problem jakarta.servlet.ServletException: Handler dispatch failed: java.lang.StackOverflowError

[Glisa060]

I'am sorry if this is the wrong place to report this problem but I feel there is a bug. Maybe it's me I don't know, problem happens on repository Save method. DTO is very simple just a field with String. Every entity has the same problem.

Generic Service

 @Transactional
  public DTO save(DTO DTO) {
    ID id = DTO.getId();
    if (id != null && !repository.existsById(id)) {
      throw new NotFoundException("ID not found");
    }

    return this.forceSave(DTO);
  }

  @Transactional
  public DTO forceSave(DTO DTO) {
      Model model = mapper.toModel(DTO);
      logger.info("DTO: {}", model.toString());
      return mapper.toDTO(repository.save(model));
  }

Mapper

@Mapper(componentModel = "spring")
public interface DrzavaMapper extends BaseMapper<Drzava, DrzavaDTO, Long> {}

Model

public class Drzava extends BaseEntity<Long> {

  @Column(nullable = false)
  private String ime;

  @OneToMany(mappedBy = "drzava")
  private Set<Grad> gradovi;
}

public class DrzavaDTO extends BaseDTO<Long> {
  @NotBlank(message = "Ime je obavezno")
  private String ime;
}

I use lombok but I omitted annotations just to make it easier to read. No @DaTa of course I know that causes recursion.
I tried @JsonIgnore @JsonBackReference an such to no avail.

@RestController
@RequestMapping("/drzave")
public class DrzavaController extends BaseController<Drzava, DrzavaDTO, Long> {
	private final DrzavaService service;

	public DrzavaController(DrzavaService service) {
		super(service);
		this.service = service;
	}
}

Steps:
http://localhost:8080/api/fakultet-service/drzave Post request

public DTO forceSave(DTO DTO) {
Model model = mapper.toModel(DTO);
logger.info("DTO: {}", model.toString());
return mapper.toDTO(repository.save(model)); << error happens here, repository.Save
}

Error: 2023-06-30T11:07:46.690+02:00 WARN 20984 --- [nio-8082-exec-7] .m.m.a.ExceptionHandlerExceptionResolver : Resolved [jakarta.servlet.ServletException: Handler dispatch failed: java.lang.StackOverflowError]

It "Resolves" error without a stack trace which is ridiculous, how to solve if I don't have information what went wrong, no stack trace nothing. Tried debugging with steps, it takes too long.

Latest Spring Boot and Cloud 3.1.1, java 17, mysql connector java latest version 8.0.33.

Again I'am sorry if this is somehow my fault. I just want to solve this and move on. Thank you.

[mp911de]

Without a stack trace nor a reproducer we're not able to diagnose where this comes from. Please attach either a stack trace showing the recursion or excessive stack depth or a reproducer.

[Glisa060]

I would gladly provide you with a stack trace. Problem is spring for some reason doesn't give one. I'm new to spring, is there a way I can force spring to provide a stack trace? Sorry for the inconvenience. It a microservice project I'am working on. I can send my whole project with multi module maven projects if that's ok.

I get this error only in console.

[schauder]

I can send my whole project with multi module maven projects if that's ok.

That is certainly not ok.

https://stackoverflow.com/help/minimal-reproducible-example recommends the following to arrive at a minimal reproducible example:

The more code there is to go through, the less likely people can find your problem. Streamline your example in one of two ways:

• Restart from scratch. Create a new program, adding in only what is needed to see the problem. Use simple, descriptive names for functions and variables – don’t copy the names you’re using in your existing code.
• Divide and conquer. If you’re not sure what the source of the problem is, start removing code a bit at a time until the problem disappears – then add the last part back.

[Glisa060]

It's a microservice, I can't make it any smaller then it already is and preserve it's functionality. Not to mention it uses generic controller, service and repository from another project. I would have to start all over again. Can somebody shed some light on error provider "jakarta.servlet.ServletException" , what causes it and I can take it from there. Thank you.

[schauder]

It's a microservice, I can't make it any smaller then it already is.

I'm sure you can. It is highly unlikely that everything that makes up the project is required to reproduce the problem.
In your original post you already pointed to a single line throwing the exception.
If that diagnosis is correct you should only need the Model class and the matching Repository to reproduce the problem.
You can set that up in a few minutes with a Spring Boot application.

You don't need a a web application, a controller, DTOs or a mapper for this.

Can somebody shed some light on error provider "jakarta.servlet.ServletException" , what causes it

A ServletException is just an exception a Servlet is allowed to throw. It gets thrown because something went wrong while a Servlet executes. In your case that "something" is most certainly the StackOverflowError. The ServletException is not relevant to the underlying problem. If you want to debug your problem, setting a break point in ExceptionHandlerExceptionResolver is probably more helpful.