[BUG][Java][Native] Lack of AnyOf class

Bug Report Checklist

[x] Have you provided a full/minimal spec to reproduce the issue?
[x] Have you validated the input using an OpenAPI validator (example)?
[ ] Have you tested with the latest master to confirm the issue still exists?
[x] Have you searched for related issues/PRs?
[x] What's the actual output vs expected output?
[ ] [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

When I'm trying to build code generated from the OpenApi spec file with "anyOf", it fails because of the lack of "AnyOfAWSPreferenceAzurePreference" class.

openapi-generator version

5.1.1

OpenAPI declaration file content or url

openapi: 3.0.1
info:
  title: Preferences Core API
  version: 1.0.0
tags:
  - name: Preferences
    description: Operations for preferences
security:
  - api_key: [ ]
paths:
  /preferences:
    get:
      summary: Returns preferences based on parameters
      tags:
        - Preferences
      parameters:
        - $ref: '#/components/parameters/Accept'
      responses:
        '200':
          $ref: '#/components/responses/GetPreferencesListResponse'

components:
  parameters:
    Accept:
      name: Accept
      in: header
      description: Defines acceptable resource representations
      required: false
      schema:
        type: string
        default: application/json

  responses:
    GetPreferencesListResponse:
      description: Describes the success response for the get preferences operation
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/PreferencesListWithIds'

  securitySchemes:
    api_key:
      type: apiKey
      name: x-api-key
      in: header
  schemas:
    PreferencesType:
      type: string
      enum:
        - AWS
        - AZURE
        - TERRAFORM
        - GITLAB

    AWSPreferenceType:
      type: string
      enum:
        - ACCESS_KEY_ID
        - ACCESS_KEY_SECRET

    AzurePreferenceType:
      type: string
      enum:
        - CLIENT_ID
        - CLIENT_SECRET
        - SUBSCRIPTION_ID
        - TENANT_ID

    PreferencesListWithIds:
      type: array
      items:
        $ref: '#/components/schemas/PreferencesWithId'

    PreferencesWithId:
      allOf:
        - properties:
           id:
            type: string
        - $ref: '#/components/schemas/Preferences'

    Preferences:
      properties:
        programId:
          type: string
        projectId:
          type: string
        labels:
          type: array
          items:
            type: string
        type:
          $ref: '#/components/schemas/PreferencesType'
        preferences:
          type: array
          items:
            anyOf:
              - $ref: '#/components/schemas/AWSPreference'
              - $ref: '#/components/schemas/AzurePreference'
      required:
        - type
        - preferences

    Preference:
      type: object
      properties:
        name:
          type: string
        value:
          type: string
        encrypted:
          type: boolean
      required:
        - encrypted
        - name
        - value

    AWSPreference:
      allOf:
        - $ref: '#/components/schemas/Preference'
        - type: object
          properties:
            name:
              $ref: '#/components/schemas/AWSPreferenceType'

    AzurePreference:
      allOf:
        - $ref: '#/components/schemas/Preference'
        - type: object
          properties:
            name:
              $ref: '#/components/schemas/AzurePreferenceType'

Generation Details

{
  "dateLibrary": "java8",
  "java8": true,
  "library": "native",
  "sourceFolder": "src/main/java",
  "serializationLibrary": "jackson"
}

Steps to reproduce

I'm using this script:

#!/usr/bin/env bash

[ ! -f openapi-generator-cli.jar ] && wget https://repo1.maven.org/maven2/org/openapitools/openapi-generator-cli/5.1.1/openapi-generator-cli-5.1.1.jar -O openapi-generator-cli.jar

LAYER=$1
SERVICE_NAME=$2
SPEC_FILE=$3
VERSION=$4
MODULE_PACKAGE=$(echo "$LAYER.$SERVICE_NAME")
MODULE_ARTIFACT=$(echo "$LAYER-$SERVICE_NAME-spec-api")

TMP_DIR=$SERVICE_NAME

rm -fr $TMP_DIR
java -jar openapi-generator-cli.jar config-help -g java > help-java.txt
java -jar openapi-generator-cli.jar generate \
         --global-property models,modelTests=false,apis,supportingFiles \
         --additional-properties=apiPackage=io.$MODULE_PACKAGE.api \
         --additional-properties=artifactDescription=$SPEC_FILE \
         --additional-properties=artifactVersion=$VERSION \
         --additional-properties=artifactId=$MODULE_ARTIFACT \
         --additional-properties=groupId=io.$LAYER \
         --additional-properties=invokerPackage=io.$MODULE_PACKAGE.client \
         --additional-properties=modelPackage=io.$MODULE_PACKAGE.api \
         -i $SPEC_FILE \
         -g java \
         -c java-config.json \
         -o $TMP_DIR
cp -r .mvn $TMP_DIR

call it with:

sh generate-models.sh feature preferences Governance-Core-PreferencesAPI-Target-V1.0.yaml 1.0.0

Related issues/PRs

Suggest a fix

I had just tested it on latest 6.0.0 snapshot and 5.2.0 snapshot locally and it is not fixed in none of those.

I have the same issue.

Using this schema

    Error:
      type: object
      example:
        timestamp: '2021-05-19T16:56:04.969+00:00'
        status: 409
        error: Conflict
        message: Application already exits
        path: /public/subscriptions
      properties:
        timestamp:
          type: string
          format: date-time
        status:
          type: integer
        error:
          type: string
        message:
          type: string
        debugMessage:
          type: string
        path:
          type: string
        errors:
          type: array
          items:
            anyOf:
              - $ref: '#/components/schemas/ValidationError'
    ValidationError:
      title: ValidationError
      type: object
      description: ''
      properties:
        object:
          type: string
        field:
          type: string
        rejectedValue:
          type: object
        message:
          type: string

and this configuration of the maven plugin:

<plugin>
<groupId>org.openapitools</groupId>
<artifactId>openapi-generator-maven-plugin</artifactId>
<version>5.1.0</version>
<executions>
    <execution>
        <id>Java Spring server stub generation</id>
        <goals>
            <goal>generate</goal>
        </goals>
        <configuration>
            <inputSpec>${project.basedir}/openapi/subscription.yaml</inputSpec>
            <generatorName>spring</generatorName>

            <generateApis>true</generateApis>
            <generateModels>true</generateModels>
            <generateModelDocumentation>false</generateModelDocumentation>
            <generateModelTests>false</generateModelTests>
            <generateSupportingFiles>true</generateSupportingFiles>

            <configOptions>
                <unhandledException>true</unhandledException>
                <library>spring-cloud</library>
                <openApiNullable>false</openApiNullable>
                <dateLibrary>java8</dateLibrary>
            </configOptions>
            <output>${project.build.directory}/generated-sources/java-server</output>
        </configuration>
    </execution>
</executions>
</plugin>

OpenAPITools / openapi-generator

[BUG][Java][Native] Lack of AnyOf class #9858