Class loader error - unnamed module of loader org.springframework.boot.devtools.restart.classloader.RestartClassLoader

Question

I am quite new to Spring and Java as a whole and I am currently working on an API. I've got this code which accesses MSSQL database, retrieves the results and IS SUPPOSED TO visualize it, but it doesn't work. I mean, if I would only call the procedure and visualize the result set, it would work normally. The problem is that I can't work with the "RatingProcedure" object. When I try get some object's value, it shows me following error:

Hibernate: {call dis_entity.spdcmpracovnici(?,?,?,?)} 2019-09-02 01:56:01.355 WARN 8720 --- [nio-8050-exec-3] .m.m.a.ExceptionHandlerExceptionResolver : Resolved [java.lang.ClassCastException: class [Ljava.lang.Object; cannot be cast to class com.pproi.dcm.ratingprocedure.RatingProcedure ([Ljava.lang.Object; is in module java.base of loader 'bootstrap'; >com.pproi.dcm.ratingprocedure.RatingProcedure is in unnamed module of loader >org.springframework.boot.devtools.restart.classloader.RestartClassLoader @7193df92)]

The code:

@GetMapping("/replacements/{sourceId}/workers")
    public ResponseEntity<List<PossibleReplacementResponseModel>> getReplacements(@PathVariable Integer sourceId,
            @RequestParam(required = false) Integer targetWorkerId,
            @RequestParam(required = false) Integer targetLineId,
            @RequestParam(required = false) String targetWorkplaces) {

        List<PossibleReplacementResponseModel> response = new ArrayList<>();

        // 400 Bad Request
        if ((targetLineId != null && targetWorkerId != null) || (targetWorkplaces != null && targetLineId == null))
            return ResponseEntity.badRequest().build();

        StoredProcedureQuery ratingProcedure = entityManager.createNamedStoredProcedureQuery("dcmrating");

        StoredProcedureQuery storedProcedure = ratingProcedure.setParameter("pk_target_worker", targetWorkerId)
                .setParameter("pk_target_sdl", targetLineId).setParameter("pk_target_workplaces", targetWorkplaces)
                .setParameter("pk_source_sdl", sourceId);

        List<RatingProcedure> ratings = storedProcedure.getResultList();

        for(RatingProcedure rating : ratings) {
            PossibleReplacementResponseModel responseModel = new PossibleReplacementResponseModel();
            Optional<Worker> _worker = workerRepository.findById(rating.getPersonalId());

            if(_worker.isPresent()) {
                Worker worker = _worker.get();
                responseModel.setId(worker.getId());
                responseModel.setName(worker.getFullName());
                responseModel.setSkills(findWorkersSkills(worker));
                responseModel.setPhysicalExamination(findWorkersMedicalExaminationEndDate(worker));
                responseModel.setExams(findWorkersExams(worker));
                responseModel.setRestrictions(findWorkersRestrictions(worker));
                responseModel.setRating(rating.getRating());
            }
            response.add(responseModel);
        }

        return ResponseEntity.ok(response);
    }

I probably even have an idea about the solution! I probably should customize my Restart Classloader as seen in here, but there my skills end and I have no idea what I should specify in the file.

Any ideas?

Thank you a lot.

Answer 1

A simple workaround is to disable the Restart by setting the system property:

spring.devtools.restart.enabled = false

For example, when using spring-boot maven plugin, launch the app this way:

mvn spring-boot:run -Dspring-boot.run.jvmArguments="-Dspring.devtools.restart.enabled=false"