How can i fix the missing query object de-serialization/un-marshalling function in generated java code from openapi 3 swagger source

Question

Hello,
in using Swagger I am a newbee.
But I'm not a newbee in using code generators. I even created a few of them for different companies.

First of all, I created a reproducible example Swagger file for you to understand my problem (see below).

openapi: "3.0.0"
info:
  title: Example for the not work swagger (de)serialization.
  version: 1.0.0
  license:
    name: No license
    url: https://choosealicense.com/no-permission/
servers:
  - url: http://localhost:9080/example
paths:
  /search:
    get:
      operationId: searchIt
      parameters:
      - name: q
        in: query
        description: >-
          A search object as one query paramater which was (de)serialized to/from
          the url als the simple types. Like described in
          "https://swagger.io/docs/specification/serialization/#query"
        required: true
        style: form
        explode: true
        schema:
          $ref: '#/components/schemas/SearchQuery'
      responses:
        200:
          description: A mandantory description.
          content:
            text/plain:
              schema:
                type: array
                items:
                  $ref: '#/components/schemas/SearchResult'
components:
  schemas:
    SearchQuery:
      type: object
      properties:
        start:
          type: string
        limit:
          type: integer
          format: int32
        FOO:
          type: string
        BAR:
          type: string
    SearchResult:
      type: object
      required:
        - entries
        - next
      properties:
        entries:  
          type: array
          items:
            $ref: '#/components/schemas/Entry'
        next:
          type: string
    Entry:
      type: object
      properties:
        id:  
          type: integer
        foo:
          type: string
        baz:
          type: string
      required:
      - id

If you uploaded it to the online Swagger editor, you see no errors, warnings or problems. If you now simulate a call to the endpoint (Try Out) in this editor you have to enter the search values as a Json object. With out a change and after execute you will see the generated url:

http://localhost:9080/example/search?start=string&limit=0&FOO=string&BAR=string

That show that the editor can serialize the query object.

So far so good, what means no problem.

Really?

If you let now generate a "jaxrs-jersey" server, download the generated zip file and run the generated demo via mvn package jetty:run you will get a ModelValidationException. Ignoring this Warning is no good idea, because if you enter the above url in the browser of your trust you get an HTTP 503.
The generated java client shows a similar shortcoming.

Ohmmm...

At the moment, after my whole investigation like asking the big brother and platforms like this, I get the suspicion that it was simply forgotten to implement the de-serialization functions in the code generators. Or maybe only forgot to generate the right annotations. But I hope not so.

Do anyone know, how i can fix the problem with the code-generators?
That primarily means, what I have to change in the above Swagger file, that the code generators can do there (whole) work. Or maybe knows someone other code-generators for java who can handle the above Swagger file.

Thanks.