How to search by filter (query) in Java with Instant types dates using interface specifications

I implemented the Specifications interface to make queries and perform filters by fields in my entity.

How to do this search when the value is of type Instant.

I’m trying in postman for GET:


and return in response only: with Code 200, but no data. This data exist in my database

My template class with spec and path


public class SpecificationTemplate {

        @Spec(path = "datetime_begin", spec = Equal.class),
        @Spec(path = "datetime_end", spec = Equal.class)
    public interface ReportSpec extends Specification<Report> {}


My controller code:


public ResponseEntity<List<ReportDTO>> getAllReports(SpecificationTemplate.ReportSpec spec, Pageable pageable) {
    log.debug("REST request to get a page of Reports");
    Page<ReportDTO> page = reportService.getAllReports(spec, pageable);
    HttpHeaders headers = PaginationUtil.generatePaginationHttpHeaders(ServletUriComponentsBuilder.fromCurrentRequest(), page);
    return ResponseEntity.ok().headers(headers).body(page.getContent());


I saw in the documentation (GitHub - tkaczmarzyk/specification-arg-resolver: An alternative API for filtering data with Spring MVC & Spring Data JPA), but the examples for using with Instant are not clear. I tried to write in postman some forms, but without success. Has anyone done this search using Instant?