[BUG][Java] generator creates inconsistent class name and class file name

Created by: hebra

Description

Trying to generate a Java client from the Vimeo OpenAPI spec. Using the openapi gradle plugin 3.3.4 with the generator 'java with any of it libraries (jersey1, jersey2, feign etc.) generates a class where the file name and the class name are inconsistent in regards to letter cases, leading to java compilation errors.

openapi-generator version

3.3.4

OpenAPI declaration file content or url

config.json

{
	"generatorName": "java",
	"library": "feign",
	"groupId": "com.vimeo",
	"modelPackage": "com.vimeo.model",
	"apiPackage": "com.vimeo.api",
	"invokerPackage": "com.vimeo",
	"basePackage": "com.vimeo",
	"dateLibrary": "java8",
	"java8": true,
	"async": true,
	"responseWrapper": "ListenableFuture",
	"useBeanValidation": true
}

build.gradle snippet

buildscript {
  repositories {
    mavenCentral()
  }
  dependencies {
    classpath "org.openapitools:openapi-generator-gradle-plugin:3.3.4"
  }
}

apply plugin: 'org.openapi.generator'

openApiGenerate {
	validateSpec = true
    configFile = "$rootDir/vimeo/config.json".toString()
    inputSpec = "$rootDir/vimeo/openapi/api.yaml".toString()
    outputDir = "$buildDir/generated".toString()
}

Command line used for generation

As the OpenAPI generator Gradle plugin is used the command line looks lile

./gradlew clean openApiGenerate

Steps to reproduce

create a new Spring Boot project (e.g. by using https://start.spring.io/)
download the api.yaml from above mentioned Vimeo GitHub repo
adjust the build.gradle to include above additions for the OpenAPI plugin
run via ./gradlew clean openApiGenerate

Results to check

after generating open the file build/generated/src/main/java/com/vimeo/model/MeVideosPrivacy.java
as you can see from the file name it is MeVideosPrivacy with a capital V and P, but inside the file the class name is 'MevideoPrivacy', with a lower-case v but again an uppercase P
some other class files are referencing the class as MeVideosPrivacy (like model/MeVideos.java) where others use MevideosPrivacy (like model/InlineObject53.java

Related issues/PRs

Kind of related is #1691

Suggest a fix

I am actually not sure if this is an issue with the Vimeo spec or the OpenAPI generator, as even the naming inconsistency is inconsistent across different files