Server Codegen Use Instants instead of Dates

[sergiolarrad]

Hello!

I've seen serveral issues posted about how to use Instants in the client side generation but none in server side.

I've already tried with the x-codegen-type: "java.time.Instant" but no success.

Is there anyone that has achieved this behaviour? At the moment my openAPi looks like this

localeStartTime:
type: string
format: date-time
description: instant in local timezone when the event started
example: "2025-09-19T13:11:21Z"
x-codegen-type: "java.time.Instant"

Using quarkus-openapi-generator-server 2.12.1
quarkus 3.26.4

Thank you in advance!

[ricardozanini]

cc @mcruzdev

[mcruzdev]

Hi @sergiolarrad,

The x-codegen-type is applied to the bean, not to individual properties. See the following example:

Pet:
  type: object
  properties:
    name:
      type: string
    description:
      type: string
    birthdate:
      type: string
      format: date-time
      description: Instant in local timezone when the event started
      example: "2025-09-19T13:11:21Z"
      x-codegen-type: "java.time.Instant" # Has no effect

As shown above, setting x-codegen-type on a property has no effect.

@EricWittmann, in my opinion, it would be really useful to support an annotation that allows overriding the type of a specific property as well. WDYT?

[mcruzdev]

@EricWittmann for your context, this is the line where we are generating as Date: https://github.com/Apicurio/apicurio-codegen/blob/28aa149f07c46940bb5e72d1b91d5a2475bb5390/core/src/main/java/io/apicurio/hub/api/codegen/OpenApi2JaxRs.java#L757

[EricWittmann]

I am cool with the idea. I'm not sure how easy/hard it will be to implement at the property level, since we are delegating to javaschema2pojo to generate the bean (java class will be Pet in your example). Worth exploring though! Hopefully js2p has some annotations or something that can drive the property type.