ProductController.java

@Controller("/product")
public class ProductController {
  @Get
  @Status(HttpStatus.OK)
  public void index() {
    throw Problem.builder()
            .withType(URI.create("https://example.org/out-of-stock"))
            .withTitle("Out of Stock")
            .withStatus(new HttpStatusType(HttpStatus.BAD_REQUEST))
            .withDetail("Item B00027Y5QG is no longer available")
            .with("product", "B00027Y5QG")
            .build();
  }
}