.xlsx file upload, swagger codegn does not generate @RequestParam for Multipartfile

Question

I have to upload transactions stored in .xlsx file. I'm trying to generate api using swagger codegen. I have browsed through every stackoverflow thread regarding the problem, but found no solution.

I do have a contract:

  /accounts/import/transactions:
    post:
      tags:
        - Account Transaction
      operationId: uploadTransactions
      requestBody:
        content:
          multipart/form-data:
            schema:
              type: object
              properties:
                file:
                  type: string
                  format: binary
      responses:
        200:
          description: 'Upload successful'
        400:
        ...

swagger dependencies:

<springfox-swagger-ui>3.0.0</springfox-swagger-ui>
<springfox-swagger2>3.0.0</springfox-swagger2>
<swagger-codegen-maven-plugin>3.0.21</swagger-codegen-maven-plugin>

The API I get is missing @RequestParam("file") MultiPartFile file. Any idea what I'm doing wrong? Does this have anything to do with Swagger versions?

@RequestMapping(value = "/accounts/import/transactions",
    produces = { "application/json" }, 
    consumes = { "multipart/form-data" },
    method = RequestMethod.POST)
default ResponseEntity<Void> uploadTransactions() {
    if(getObjectMapper().isPresent() && getAcceptHeader().isPresent()) {
    } else {
        log.warn("ObjectMapper or HttpServletRequest not configured in default AccountsApi interface so no example is generated");
    }
    return new ResponseEntity<>(HttpStatus.NOT_IMPLEMENTED);
}