class OutOfStockException extends RuntimeException {
}

class OutOfStockException : RuntimeException()

@Controller("/books")
class BookController {
    @Produces(MediaType.TEXT_PLAIN)
    @Get("/stock/{isbn}")
    Integer stock(String isbn) {
        throw new OutOfStockException()
    }
}

@Controller("/books")
    @Produces(MediaType.TEXT_PLAIN)
    @Get("/stock/{isbn}")
    internal fun stock(isbn: String): Int? {
        throw OutOfStockException()
    }
}

@Produces
@Singleton
@Requires(classes = [OutOfStockException.class, ExceptionHandler.class])
class OutOfStockExceptionHandler implements ExceptionHandler<OutOfStockException, HttpResponse> {
    @Override
    }
}

@Produces
@Singleton
@Requirements(
        Requires(classes = [OutOfStockException::class, ExceptionHandler::class])
)
class OutOfStockExceptionHandler : ExceptionHandler<OutOfStockException, HttpResponse<*>> {
    override fun handle(request: HttpRequest<*>, exception: OutOfStockException): HttpResponse<*> {
        return HttpResponse.ok(0)
    }