[kotlin-server][javalin6] Add Javalin 6 support (#18928)

* [kotlin-server][javalin6] Add Javalin 6 support

Javalin 5 support was added in 13edc5d. Javalin 6 has been released, with some breaking changes. Let's add a new supportedLibrary to not break existing users of Javalin 5.

https://javalin.io/migration-guide-javalin-5-to-6

* Fix Gradle config and don't include JVM 8 CI anymore (JVM 11 is the minimum for Javalin)

* Update docs

* Fix optional query parameter handling and turn into expected type

.github/workflows/samples-kotlin-server-jdk17.yaml

@@ -1,16 +1,18 @@
-name: Samples Kotlin server
+name: Samples Kotlin server (jdk17)
 
 on:
   push:
     branches:
       - 'samples/server/petstore/kotlin-springboot-3*/**'
       - 'samples/server/petstore/kotlin-server/javalin/**'
+      - 'samples/server/petstore/kotlin-server/javalin-6/**'
       # comment out due to gradle build failure
       # - samples/server/petstore/kotlin-spring-default/**
   pull_request:
     paths:
       - 'samples/server/petstore/kotlin-springboot-3*/**'
       - 'samples/server/petstore/kotlin-server/javalin/**'
+      - 'samples/server/petstore/kotlin-server/javalin-6/**'
       # comment out due to gradle build failure
       # - samples/server/petstore/kotlin-spring-default/**
 
@@ -30,6 +32,7 @@ jobs:
           - samples/server/petstore/kotlin-springboot-request
           - samples/server/petstore/kotlin-springboot-request-cookie
           - samples/server/petstore/kotlin-server/javalin
+          - samples/server/petstore/kotlin-server/javalin-6
           # comment out due to gradle build failure
           # - samples/server/petstore/kotlin-spring-default/
     steps:

.github/workflows/samples-kotlin-server-jdk21.yaml

@@ -0,0 +1,45 @@
+name: Samples Kotlin server (jdk21)
+
+on:
+  push:
+    branches:
+      - 'samples/server/petstore/kotlin-server/javalin-6/**'
+  pull_request:
+    paths:
+      - 'samples/server/petstore/kotlin-server/javalin-6/**'
+
+env:
+  GRADLE_VERSION: 8.8
+
+jobs:
+  build:
+    name: Build Kotlin server
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        sample:
+          - samples/server/petstore/kotlin-server/javalin-6
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: 21
+      - name: Cache maven dependencies
+        uses: actions/cache@v4
+        env:
+          cache-name: maven-repository
+        with:
+          path: |
+            ~/.gradle
+          key: ${{ runner.os }}-${{ github.job }}-${{ env.cache-name }}-${{ hashFiles('**/pom.xml') }}
+      - name: Install Gradle wrapper
+        uses: eskatos/gradle-command-action@v3
+        with:
+          gradle-version: ${{ env.GRADLE_VERSION }}
+          build-root-directory: ${{ matrix.sample }}
+          arguments: wrapper
+      - name: Build
+        working-directory: ${{ matrix.sample }}
+        run: ./gradlew build -x test

bin/configs/kotlin-server-javalin-6.yaml

@@ -0,0 +1,7 @@
+generatorName: kotlin-server
+outputDir: samples/server/petstore/kotlin-server/javalin-6
+library: javalin6
+inputSpec: modules/openapi-generator/src/test/resources/3_0/petstore.yaml
+templateDir: modules/openapi-generator/src/main/resources/kotlin-server
+additionalProperties:
+  hideGenerationTimestamp: "true"

docs/generators/kotlin-server.md

@@ -32,7 +32,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |featureResources|Generates routes in a typed way, for both: constructing URLs and reading the parameters.| |true|
 |groupId|Generated artifact package's organization (i.e. maven groupId).| |org.openapitools|
 |interfaceOnly|Whether to generate only API interface stubs without the server files. This option is currently supported only when using jaxrs-spec library.| |false|
-|library|library template (sub-template)|<dl><dt>**ktor**</dt><dd>ktor framework</dd><dt>**jaxrs-spec**</dt><dd>JAX-RS spec only</dd><dt>**javalin5**</dt><dd>Javalin 5</dd></dl>|ktor|
+|library|library template (sub-template)|<dl><dt>**ktor**</dt><dd>ktor framework</dd><dt>**jaxrs-spec**</dt><dd>JAX-RS spec only</dd><dt>**javalin5**</dt><dd>Javalin 5</dd><dt>**javalin6**</dt><dd>Javalin 6</dd></dl>|ktor|
 |modelMutable|Create mutable models| |false|
 |omitGradleWrapper|Whether to omit Gradle wrapper for creating a sub project.| |false|
 |packageName|Generated artifact package name.| |org.openapitools.server|

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/KotlinServerCodegen.java

@@ -27,6 +27,7 @@ import org.openapitools.codegen.meta.features.*;
 import org.openapitools.codegen.model.ModelMap;
 import org.openapitools.codegen.model.OperationMap;
 import org.openapitools.codegen.model.OperationsMap;
+import org.openapitools.codegen.templating.mustache.CamelCaseLambda;
 import org.openapitools.codegen.templating.mustache.LowercaseLambda;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -128,6 +129,7 @@ public class KotlinServerCodegen extends AbstractKotlinCodegen implements BeanVa
         supportedLibraries.put(Constants.KTOR, "ktor framework");
         supportedLibraries.put(Constants.JAXRS_SPEC, "JAX-RS spec only");
         supportedLibraries.put(Constants.JAVALIN5, "Javalin 5");
+        supportedLibraries.put(Constants.JAVALIN6, "Javalin 6");
 
         // TODO: Configurable server engine. Defaults to netty in build.gradle.
         addOption(CodegenConstants.LIBRARY, CodegenConstants.LIBRARY_DESC, DEFAULT_LIBRARY, supportedLibraries);
@@ -276,7 +278,7 @@ public class KotlinServerCodegen extends AbstractKotlinCodegen implements BeanVa
 
         String gradleBuildFile = "build.gradle";
 
-        if (library.equals(Constants.JAVALIN5)) {
+        if (isJavalin()) {
             gradleBuildFile = "build.gradle.kts";
         }
 
@@ -298,11 +300,12 @@ public class KotlinServerCodegen extends AbstractKotlinCodegen implements BeanVa
             final String infrastructureFolder = (sourceFolder + File.separator + packageName + File.separator + "infrastructure").replace(".", File.separator);
 
             supportingFiles.add(new SupportingFile("ApiKeyAuth.kt.mustache", infrastructureFolder, "ApiKeyAuth.kt"));
-        } else if (library.equals(Constants.JAVALIN5)) {
+        } else if (isJavalin()) {
             supportingFiles.add(new SupportingFile("Main.kt.mustache", packageFolder, "Main.kt"));
             apiTemplateFiles.put("service.mustache", "Service.kt");
             apiTemplateFiles.put("serviceImpl.mustache", "ServiceImpl.kt");
             additionalProperties.put("lowercase", new LowercaseLambda());
+            additionalProperties.put("camelcase", new CamelCaseLambda());
             typeMapping.put("file", "io.javalin.http.UploadedFile");
             importMapping.put("io.javalin.http.UploadedFile", "io.javalin.http.UploadedFile");
         }
@@ -318,6 +321,7 @@ public class KotlinServerCodegen extends AbstractKotlinCodegen implements BeanVa
         public final static String JAXRS_SPEC = "jaxrs-spec";
 
         public final static String JAVALIN5 = "javalin5";
+        public final static String JAVALIN6 = "javalin6";
         public final static String AUTOMATIC_HEAD_REQUESTS = "featureAutoHead";
         public final static String AUTOMATIC_HEAD_REQUESTS_DESC = "Automatically provide responses to HEAD requests for existing routes that have the GET verb defined.";
         public final static String CONDITIONAL_HEADERS = "featureConditionalHeaders";
@@ -404,4 +408,8 @@ public class KotlinServerCodegen extends AbstractKotlinCodegen implements BeanVa
 
         return objs;
     }
+
+    private boolean isJavalin() {
+        return Constants.JAVALIN5.equals(library) || Constants.JAVALIN6.equals(library);
+    }
 }

modules/openapi-generator/src/main/resources/kotlin-server/libraries/javalin6/Main.kt.mustache

@@ -0,0 +1,36 @@
+package {{packageName}}
+
+import io.javalin.Javalin
+import io.javalin.apibuilder.ApiBuilder.*
+
+{{#apiInfo}}
+{{#apis}}
+{{#operations}}import {{apiPackage}}.{{classname}}
+import {{apiPackage}}.{{classname}}ServiceImpl
+{{/operations}}
+{{/apis}}
+
+fun main() {
+    {{#apis}}
+    {{#operations}}
+    val {{#camelcase}}{{classname}}{{/camelcase}} = {{classname}}({{classname}}ServiceImpl())
+    {{/operations}}
+    {{/apis}}
+
+    val app = Javalin
+        .create { config ->
+            config.router.apiBuilder {
+                {{#apis}}
+                {{#operations}}
+                {{#operation}}
+                path("{{path}}") { {{#lowercase}}{{httpMethod}}{{/lowercase}}({{#camelcase}}{{classname}}{{/camelcase}}::{{operationId}}) }
+                {{/operation}}
+                {{/operations}}
+
+                {{/apis}}
+            }
+        }
+
+    app.start({{serverPort}})
+}
+{{/apiInfo}}

modules/openapi-generator/src/main/resources/kotlin-server/libraries/javalin6/README.mustache

@@ -0,0 +1,94 @@
+# {{packageName}} - Kotlin Server library for {{appName}}
+
+{{#unescapedAppDescription}}
+{{.}}
+{{/unescapedAppDescription}}
+
+Generated by OpenAPI Generator {{generatorVersion}}{{^hideGenerationTimestamp}} ({{generatedDate}}){{/hideGenerationTimestamp}}.
+
+## Build
+
+First, create the gradle wrapper script:
+
+```
+gradle wrapper
+```
+
+Then, run:
+
+```
+./gradlew check assemble
+```
+
+This runs all tests and packages the library.
+
+## Running
+
+The server builds as a fat jar with a main entrypoint. To start the service, run `java -jar ./build/libs/{{artifactId}}.jar`.
+
+You may also run in docker:
+
+```
+docker build -t {{artifactId}} .
+docker run -p 8080:8080 {{artifactId}}
+```
+
+## Features/Implementation Notes
+
+* Supports JSON inputs/outputs, File inputs, and Form inputs (see ktor documentation for more info).
+* ~Supports collection formats for query parameters: csv, tsv, ssv, pipes.~
+* Some Kotlin and Java types are fully qualified to avoid conflicts with types defined in OpenAPI definitions.
+
+{{#generateApiDocs}}
+<a id="documentation-for-api-endpoints"></a>
+## Documentation for API Endpoints
+
+All URIs are relative to *{{{basePath}}}*
+
+Class | Method | HTTP request | Description
+------------ | ------------- | ------------- | -------------
+{{#apiInfo}}{{#apis}}{{#operations}}{{#operation}}*{{classname}}* | [**{{operationId}}**]({{apiDocPath}}{{classname}}.md#{{operationIdLowerCase}}) | **{{httpMethod}}** {{path}} | {{{summary}}}
+{{/operation}}{{/operations}}{{/apis}}{{/apiInfo}}
+{{/generateApiDocs}}
+
+{{#generateModelDocs}}
+<a id="documentation-for-models"></a>
+## Documentation for Models
+
+{{#modelPackage}}
+{{#models}}{{#model}} - [{{{modelPackage}}}.{{{classname}}}]({{modelDocPath}}{{{classname}}}.md)
+{{/model}}{{/models}}
+{{/modelPackage}}
+{{^modelPackage}}
+No model defined in this package
+{{/modelPackage}}
+{{/generateModelDocs}}
+
+<a id="documentation-for-authorization"></a>
+## Documentation for Authorization
+
+{{^authMethods}}Endpoints do not require authorization.{{/authMethods}}
+{{#hasAuthMethods}}Authentication schemes defined for the API:{{/hasAuthMethods}}
+{{#authMethods}}
+<a id="{{name}}"></a>
+### {{name}}
+
+{{#isApiKey}}- **Type**: API key
+- **API key parameter name**: {{keyParamName}}
+- **Location**: {{#isKeyInQuery}}URL query string{{/isKeyInQuery}}{{#isKeyInHeader}}HTTP header{{/isKeyInHeader}}
+{{/isApiKey}}
+{{#isBasicBasic}}- **Type**: HTTP basic authentication
+{{/isBasicBasic}}
+{{#isBasicBearer}}- **Type**: HTTP Bearer Token authentication{{#bearerFormat}} ({{{.}}}){{/bearerFormat}}
+{{/isBasicBearer}}
+{{#isHttpSignature}}- **Type**: HTTP signature authentication
+{{/isHttpSignature}}
+{{#isOAuth}}- **Type**: OAuth
+- **Flow**: {{flow}}
+- **Authorization URL**: {{authorizationUrl}}
+- **Scopes**: {{^scopes}}N/A{{/scopes}}
+{{#scopes}}  - {{scope}}: {{description}}
+{{/scopes}}
+{{/isOAuth}}
+
+{{/authMethods}}

modules/openapi-generator/src/main/resources/kotlin-server/libraries/javalin6/api.mustache

@@ -0,0 +1,26 @@
+package {{apiPackage}}
+
+import io.javalin.http.Context
+import io.javalin.http.bodyAsClass
+import io.javalin.http.pathParamAsClass
+import io.javalin.http.queryParamAsClass
+
+{{#imports}}import {{import}}
+{{/imports}}
+
+{{#operations}}
+class {{classname}}(private val service: {{classname}}Service) {
+    {{#operation}}
+    /**{{#summary}}
+     * {{.}}{{/summary}}
+     * {{unescapedNotes}}
+     {{#allParams}}* @param {{paramName}} {{description}} {{^required}}(optional{{#defaultValue}}, default to {{{.}}}{{/defaultValue}}){{/required}}
+     {{/allParams}}*/
+    fun {{operationId}}(ctx: Context) {
+        val result = service.{{operationId}}({{#allParams}}{{>queryParams}}{{>pathParams}}{{>headerParams}}{{>bodyParams}}{{>formParams}}{{^-last}}, {{/-last}}{{/allParams}}{{#hasParams}}, {{/hasParams}}ctx)
+        ctx.status({{#responses}}{{#-first}}{{code}}{{/-first}}{{/responses}}).json(result)
+    }
+
+    {{/operation}}
+}
+{{/operations}}

modules/openapi-generator/src/main/resources/kotlin-server/libraries/javalin6/bodyParams.mustache

@@ -0,0 +1 @@
+{{#isBodyParam}}{{#isArray}}ctx.bodyAsClass<List<{{{baseType}}}>>(){{/isArray}}{{^isArray}}ctx.bodyAsClass<{{{baseType}}}>(){{/isArray}}{{/isBodyParam}}

modules/openapi-generator/src/main/resources/kotlin-server/libraries/javalin6/build.gradle.kts.mustache

@@ -0,0 +1,33 @@
+plugins {
+    kotlin("jvm") version "2.0.0"
+}
+
+group = "{{groupId}}"
+version = "{{artifactVersion}}"
+
+kotlin {
+    jvmToolchain(21)
+}
+
+java {
+    toolchain {
+        languageVersion.set(JavaLanguageVersion.of(21))
+    }
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation("io.javalin:javalin:6.1.6")
+    implementation("com.fasterxml.jackson.core:jackson-databind:2.17.1")
+    implementation("com.fasterxml.jackson.module:jackson-module-kotlin:2.17.1")
+    implementation("org.slf4j:slf4j-simple:2.0.13")
+
+    testImplementation("org.jetbrains.kotlin:kotlin-test")
+}
+
+tasks.test {
+    useJUnitPlatform()
+}

modules/openapi-generator/src/main/resources/kotlin-server/libraries/javalin6/formParams.mustache

@@ -0,0 +1 @@
+{{#isFormParam}}{{^isFile}}ctx.formParam("{{baseName}}"){{/isFile}}{{#isFile}}ctx.uploadedFile("{{baseName}}"){{/isFile}}{{/isFormParam}}

modules/openapi-generator/src/main/resources/kotlin-server/libraries/javalin6/gradle.properties

@@ -0,0 +1 @@
+org.gradle.caching=true

modules/openapi-generator/src/main/resources/kotlin-server/libraries/javalin6/headerParams.mustache

@@ -0,0 +1 @@
+{{#isHeaderParam}}ctx.header("{{baseName}}"){{/isHeaderParam}}

modules/openapi-generator/src/main/resources/kotlin-server/libraries/javalin6/optionalDataType.mustache

@@ -0,0 +1 @@
+{{#required}}{{{dataType}}}{{/required}}{{^required}}{{#defaultValue}}{{{dataType}}}{{/defaultValue}}{{^defaultValue}}{{{dataType}}}?{{/defaultValue}}{{/required}}

modules/openapi-generator/src/main/resources/kotlin-server/libraries/javalin6/pathParams.mustache

@@ -0,0 +1 @@
+{{#isPathParam}}ctx.pathParamAsClass<{{{dataType}}}>("{{baseName}}").get(){{/isPathParam}}

modules/openapi-generator/src/main/resources/kotlin-server/libraries/javalin6/queryParams.mustache

@@ -0,0 +1 @@
+{{#isQueryParam}}{{#isArray}}ctx.queryParams("{{baseName}}"){{/isArray}}{{^isArray}}ctx.queryParamAsClass<{{{dataType}}}>("{{baseName}}"){{^required}}.allowNullable(){{/required}}.get(){{/isArray}}{{/isQueryParam}}

modules/openapi-generator/src/main/resources/kotlin-server/libraries/javalin6/returnTypes.mustache

@@ -0,0 +1 @@
+{{#isMap}}Map<String, {{{returnType}}}>{{/isMap}}{{#isArray}}{{#reactive}}Flow{{/reactive}}{{^reactive}}{{{returnContainer}}}{{/reactive}}<{{{returnType}}}>{{/isArray}}{{^returnContainer}}{{{returnType}}}{{/returnContainer}}

modules/openapi-generator/src/main/resources/kotlin-server/libraries/javalin6/service.mustache

@@ -0,0 +1,35 @@
+package {{package}}
+
+{{#imports}}import {{import}}
+{{/imports}}
+import io.javalin.http.Context
+
+{{#operations}}
+interface {{classname}}Service {
+{{#operation}}
+
+    /**
+     * {{httpMethod}} {{{path}}}{{#summary}} : {{.}}{{/summary}}
+    {{#notes}}
+     * {{.}}
+    {{/notes}}
+     *
+    {{#allParams}}
+     * @param {{{paramName}}} {{description}}{{#required}} (required){{/required}}{{^required}} (optional{{#defaultValue}}, default to {{.}}{{/defaultValue}}){{/required}}
+    {{/allParams}}
+     * @param ctx The Javalin context. Especially handy if you need to access things like authentication headers in your service. (required)
+     * @return {{#responses}}{{message}} (status code {{code}}){{^-last}}
+     *         or {{/-last}}{{/responses}}
+    {{#isDeprecated}}
+     * @deprecated
+    {{/isDeprecated}}
+    {{#externalDocs}}
+     * {{description}}
+     * @see <a href="{{url}}">{{summary}} Documentation</a>
+    {{/externalDocs}}
+     * @see {{classname}}#{{operationId}}
+     */
+    {{#reactive}}{{^isArray}}suspend {{/isArray}}{{/reactive}}fun {{operationId}}({{#allParams}}{{{paramName}}}: {{^isBodyParam}}{{>optionalDataType}}{{/isBodyParam}}{{#isBodyParam}}{{^reactive}}{{>optionalDataType}}{{/reactive}}{{#reactive}}{{^isArray}}{{>optionalDataType}}{{/isArray}}{{#isArray}}Flow<{{{baseType}}}>{{/isArray}}{{/reactive}}{{/isBodyParam}}{{^-last}}, {{/-last}}{{/allParams}}{{#hasParams}}, {{/hasParams}}ctx: Context): {{>returnTypes}}
+{{/operation}}
+}
+{{/operations}}

modules/openapi-generator/src/main/resources/kotlin-server/libraries/javalin6/serviceImpl.mustache

@@ -0,0 +1,19 @@
+package {{package}}
+
+{{#imports}}import {{import}}
+{{/imports}}
+import io.javalin.http.Context
+{{#reactive}}
+import kotlinx.coroutines.flow.Flow
+{{/reactive}}
+{{#operations}}
+
+class {{classname}}ServiceImpl : {{classname}}Service {
+{{#operation}}
+
+    override {{#reactive}}{{^isArray}}suspend {{/isArray}}{{/reactive}}fun {{operationId}}({{#allParams}}{{paramName}}: {{^isBodyParam}}{{>optionalDataType}}{{/isBodyParam}}{{#isBodyParam}}{{^reactive}}{{>optionalDataType}}{{/reactive}}{{#reactive}}{{^isArray}}{{>optionalDataType}}{{/isArray}}{{#isArray}}Flow<{{{baseType}}}>{{/isArray}}{{/reactive}}{{/isBodyParam}}{{^-last}}, {{/-last}}{{/allParams}}{{#hasParams}}, {{/hasParams}}ctx: Context): {{>returnTypes}} {
+        TODO("Implement me")
+    }
+{{/operation}}
+}
+{{/operations}}

samples/server/petstore/kotlin-server/javalin-6/.openapi-generator-ignore

@@ -0,0 +1,23 @@
+# OpenAPI Generator Ignore
+# Generated by openapi-generator https://github.com/openapitools/openapi-generator
+
+# Use this file to prevent files from being overwritten by the generator.
+# The patterns follow closely to .gitignore or .dockerignore.
+
+# As an example, the C# client generator defines ApiClient.cs.
+# You can make changes and tell OpenAPI Generator to ignore just this file by uncommenting the following line:
+#ApiClient.cs
+
+# You can match any string of characters against a directory, file or extension with a single asterisk (*):
+#foo/*/qux
+# The above matches foo/bar/qux and foo/baz/qux, but not foo/bar/baz/qux
+
+# You can recursively match patterns against a directory, file or extension with a double asterisk (**):
+#foo/**/qux
+# This matches foo/bar/qux, foo/baz/qux, and foo/bar/baz/qux
+
+# You can also negate patterns with an exclamation (!).
+# For example, you can ignore all files in a docs folder with the file extension .md:
+#docs/*.md
+# Then explicitly reverse the ignore rule for a single file:
+#!docs/README.md

samples/server/petstore/kotlin-server/javalin-6/.openapi-generator/FILES

@@ -0,0 +1,20 @@
+README.md
+build.gradle.kts
+gradle.properties
+settings.gradle
+src/main/kotlin/org/openapitools/server/Main.kt
+src/main/kotlin/org/openapitools/server/apis/PetApi.kt
+src/main/kotlin/org/openapitools/server/apis/PetApiService.kt
+src/main/kotlin/org/openapitools/server/apis/PetApiServiceImpl.kt
+src/main/kotlin/org/openapitools/server/apis/StoreApi.kt
+src/main/kotlin/org/openapitools/server/apis/StoreApiService.kt
+src/main/kotlin/org/openapitools/server/apis/StoreApiServiceImpl.kt
+src/main/kotlin/org/openapitools/server/apis/UserApi.kt
+src/main/kotlin/org/openapitools/server/apis/UserApiService.kt
+src/main/kotlin/org/openapitools/server/apis/UserApiServiceImpl.kt
+src/main/kotlin/org/openapitools/server/models/Category.kt
+src/main/kotlin/org/openapitools/server/models/ModelApiResponse.kt
+src/main/kotlin/org/openapitools/server/models/Order.kt
+src/main/kotlin/org/openapitools/server/models/Pet.kt
+src/main/kotlin/org/openapitools/server/models/Tag.kt
+src/main/kotlin/org/openapitools/server/models/User.kt

samples/server/petstore/kotlin-server/javalin-6/.openapi-generator/VERSION

@@ -0,0 +1 @@
+7.7.0-SNAPSHOT

samples/server/petstore/kotlin-server/javalin-6/README.md

@@ -0,0 +1,101 @@
+# org.openapitools.server - Kotlin Server library for OpenAPI Petstore
+
+This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+
+Generated by OpenAPI Generator 7.7.0-SNAPSHOT.
+
+## Build
+
+First, create the gradle wrapper script:
+
+```
+gradle wrapper
+```
+
+Then, run:
+
+```
+./gradlew check assemble
+```
+
+This runs all tests and packages the library.
+
+## Running
+
+The server builds as a fat jar with a main entrypoint. To start the service, run `java -jar ./build/libs/kotlin-server.jar`.
+
+You may also run in docker:
+
+```
+docker build -t kotlin-server .
+docker run -p 8080:8080 kotlin-server
+```
+
+## Features/Implementation Notes
+
+* Supports JSON inputs/outputs, File inputs, and Form inputs (see ktor documentation for more info).
+* ~Supports collection formats for query parameters: csv, tsv, ssv, pipes.~
+* Some Kotlin and Java types are fully qualified to avoid conflicts with types defined in OpenAPI definitions.
+
+<a id="documentation-for-api-endpoints"></a>
+## Documentation for API Endpoints
+
+All URIs are relative to *http://petstore.swagger.io/v2*
+
+Class | Method | HTTP request | Description
+------------ | ------------- | ------------- | -------------
+*PetApi* | [**addPet**](docs/PetApi.md#addpet) | **POST** /pet | Add a new pet to the store
+*PetApi* | [**deletePet**](docs/PetApi.md#deletepet) | **DELETE** /pet/{petId} | Deletes a pet
+*PetApi* | [**findPetsByStatus**](docs/PetApi.md#findpetsbystatus) | **GET** /pet/findByStatus | Finds Pets by status
+*PetApi* | [**findPetsByTags**](docs/PetApi.md#findpetsbytags) | **GET** /pet/findByTags | Finds Pets by tags
+*PetApi* | [**getPetById**](docs/PetApi.md#getpetbyid) | **GET** /pet/{petId} | Find pet by ID
+*PetApi* | [**updatePet**](docs/PetApi.md#updatepet) | **PUT** /pet | Update an existing pet
+*PetApi* | [**updatePetWithForm**](docs/PetApi.md#updatepetwithform) | **POST** /pet/{petId} | Updates a pet in the store with form data
+*PetApi* | [**uploadFile**](docs/PetApi.md#uploadfile) | **POST** /pet/{petId}/uploadImage | uploads an image
+*StoreApi* | [**deleteOrder**](docs/StoreApi.md#deleteorder) | **DELETE** /store/order/{orderId} | Delete purchase order by ID
+*StoreApi* | [**getInventory**](docs/StoreApi.md#getinventory) | **GET** /store/inventory | Returns pet inventories by status
+*StoreApi* | [**getOrderById**](docs/StoreApi.md#getorderbyid) | **GET** /store/order/{orderId} | Find purchase order by ID
+*StoreApi* | [**placeOrder**](docs/StoreApi.md#placeorder) | **POST** /store/order | Place an order for a pet
+*UserApi* | [**createUser**](docs/UserApi.md#createuser) | **POST** /user | Create user
+*UserApi* | [**createUsersWithArrayInput**](docs/UserApi.md#createuserswitharrayinput) | **POST** /user/createWithArray | Creates list of users with given input array
+*UserApi* | [**createUsersWithListInput**](docs/UserApi.md#createuserswithlistinput) | **POST** /user/createWithList | Creates list of users with given input array
+*UserApi* | [**deleteUser**](docs/UserApi.md#deleteuser) | **DELETE** /user/{username} | Delete user
+*UserApi* | [**getUserByName**](docs/UserApi.md#getuserbyname) | **GET** /user/{username} | Get user by user name
+*UserApi* | [**loginUser**](docs/UserApi.md#loginuser) | **GET** /user/login | Logs user into the system
+*UserApi* | [**logoutUser**](docs/UserApi.md#logoutuser) | **GET** /user/logout | Logs out current logged in user session
+*UserApi* | [**updateUser**](docs/UserApi.md#updateuser) | **PUT** /user/{username} | Updated user
+
+
+<a id="documentation-for-models"></a>
+## Documentation for Models
+
+ - [org.openapitools.server.models.Category](docs/Category.md)
+ - [org.openapitools.server.models.ModelApiResponse](docs/ModelApiResponse.md)
+ - [org.openapitools.server.models.Order](docs/Order.md)
+ - [org.openapitools.server.models.Pet](docs/Pet.md)
+ - [org.openapitools.server.models.Tag](docs/Tag.md)
+ - [org.openapitools.server.models.User](docs/User.md)
+
+
+<a id="documentation-for-authorization"></a>
+## Documentation for Authorization
+
+
+Authentication schemes defined for the API:
+<a id="petstore_auth"></a>
+### petstore_auth
+
+- **Type**: OAuth
+- **Flow**: implicit
+- **Authorization URL**: http://petstore.swagger.io/api/oauth/dialog
+- **Scopes**: 
+  - write:pets: modify pets in your account
+  - read:pets: read your pets
+
+<a id="api_key"></a>
+### api_key
+
+- **Type**: API key
+- **API key parameter name**: api_key
+- **Location**: HTTP header
+

samples/server/petstore/kotlin-server/javalin-6/build.gradle.kts

@@ -0,0 +1,33 @@
+plugins {
+    kotlin("jvm") version "2.0.0"
+}
+
+group = "org.openapitools"
+version = "1.0.0"
+
+kotlin {
+    jvmToolchain(21)
+}
+
+java {
+    toolchain {
+        languageVersion.set(JavaLanguageVersion.of(21))
+    }
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation("io.javalin:javalin:6.1.6")
+    implementation("com.fasterxml.jackson.core:jackson-databind:2.17.1")
+    implementation("com.fasterxml.jackson.module:jackson-module-kotlin:2.17.1")
+    implementation("org.slf4j:slf4j-simple:2.0.13")
+
+    testImplementation("org.jetbrains.kotlin:kotlin-test")
+}
+
+tasks.test {
+    useJUnitPlatform()
+}

samples/server/petstore/kotlin-server/javalin-6/gradle.properties

@@ -0,0 +1 @@
+org.gradle.caching=true

samples/server/petstore/kotlin-server/javalin-6/settings.gradle

@@ -0,0 +1 @@
+rootProject.name = 'kotlin-server'

samples/server/petstore/kotlin-server/javalin-6/src/main/kotlin/org/openapitools/server/Main.kt

@@ -0,0 +1,48 @@
+package org.openapitools.server
+
+import io.javalin.Javalin
+import io.javalin.apibuilder.ApiBuilder.*
+
+import org.openapitools.server.apis.PetApi
+import org.openapitools.server.apis.PetApiServiceImpl
+import org.openapitools.server.apis.StoreApi
+import org.openapitools.server.apis.StoreApiServiceImpl
+import org.openapitools.server.apis.UserApi
+import org.openapitools.server.apis.UserApiServiceImpl
+
+fun main() {
+    val petApi = PetApi(PetApiServiceImpl())
+    val storeApi = StoreApi(StoreApiServiceImpl())
+    val userApi = UserApi(UserApiServiceImpl())
+
+    val app = Javalin
+        .create { config ->
+            config.router.apiBuilder {
+                path("/pet") { post(petApi::addPet) }
+                path("/pet/{petId}") { delete(petApi::deletePet) }
+                path("/pet/findByStatus") { get(petApi::findPetsByStatus) }
+                path("/pet/findByTags") { get(petApi::findPetsByTags) }
+                path("/pet/{petId}") { get(petApi::getPetById) }
+                path("/pet") { put(petApi::updatePet) }
+                path("/pet/{petId}") { post(petApi::updatePetWithForm) }
+                path("/pet/{petId}/uploadImage") { post(petApi::uploadFile) }
+
+                path("/store/order/{orderId}") { delete(storeApi::deleteOrder) }
+                path("/store/inventory") { get(storeApi::getInventory) }
+                path("/store/order/{orderId}") { get(storeApi::getOrderById) }
+                path("/store/order") { post(storeApi::placeOrder) }
+
+                path("/user") { post(userApi::createUser) }
+                path("/user/createWithArray") { post(userApi::createUsersWithArrayInput) }
+                path("/user/createWithList") { post(userApi::createUsersWithListInput) }
+                path("/user/{username}") { delete(userApi::deleteUser) }
+                path("/user/{username}") { get(userApi::getUserByName) }
+                path("/user/login") { get(userApi::loginUser) }
+                path("/user/logout") { get(userApi::logoutUser) }
+                path("/user/{username}") { put(userApi::updateUser) }
+
+            }
+        }
+
+    app.start()
+}

samples/server/petstore/kotlin-server/javalin-6/src/main/kotlin/org/openapitools/server/apis/PetApi.kt

@@ -0,0 +1,97 @@
+package org.openapitools.server.apis
+
+import io.javalin.http.Context
+import io.javalin.http.bodyAsClass
+import io.javalin.http.pathParamAsClass
+import io.javalin.http.queryParamAsClass
+
+import org.openapitools.server.models.ModelApiResponse
+import org.openapitools.server.models.Pet
+
+class PetApi(private val service: PetApiService) {
+    /**
+     * Add a new pet to the store
+     * 
+     * @param pet Pet object that needs to be added to the store 
+     */
+    fun addPet(ctx: Context) {
+        val result = service.addPet(ctx.bodyAsClass<Pet>(), ctx)
+        ctx.status(200).json(result)
+    }
+
+    /**
+     * Deletes a pet
+     * 
+     * @param petId Pet id to delete 
+     * @param apiKey  (optional)
+     */
+    fun deletePet(ctx: Context) {
+        val result = service.deletePet(ctx.pathParamAsClass<kotlin.Long>("petId").get(), ctx.header("api_key"), ctx)
+        ctx.status(400).json(result)
+    }
+
+    /**
+     * Finds Pets by status
+     * Multiple status values can be provided with comma separated strings
+     * @param status Status values that need to be considered for filter 
+     */
+    fun findPetsByStatus(ctx: Context) {
+        val result = service.findPetsByStatus(ctx.queryParams("status"), ctx)
+        ctx.status(200).json(result)
+    }
+
+    /**
+     * Finds Pets by tags
+     * Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
+     * @param tags Tags to filter by 
+     */
+    fun findPetsByTags(ctx: Context) {
+        val result = service.findPetsByTags(ctx.queryParams("tags"), ctx)
+        ctx.status(200).json(result)
+    }
+
+    /**
+     * Find pet by ID
+     * Returns a single pet
+     * @param petId ID of pet to return 
+     */
+    fun getPetById(ctx: Context) {
+        val result = service.getPetById(ctx.pathParamAsClass<kotlin.Long>("petId").get(), ctx)
+        ctx.status(200).json(result)
+    }
+
+    /**
+     * Update an existing pet
+     * 
+     * @param pet Pet object that needs to be added to the store 
+     */
+    fun updatePet(ctx: Context) {
+        val result = service.updatePet(ctx.bodyAsClass<Pet>(), ctx)
+        ctx.status(200).json(result)
+    }
+
+    /**
+     * Updates a pet in the store with form data
+     * 
+     * @param petId ID of pet that needs to be updated 
+     * @param name Updated name of the pet (optional)
+     * @param status Updated status of the pet (optional)
+     */
+    fun updatePetWithForm(ctx: Context) {
+        val result = service.updatePetWithForm(ctx.pathParamAsClass<kotlin.Long>("petId").get(), ctx.formParam("name"), ctx.formParam("status"), ctx)
+        ctx.status(405).json(result)
+    }
+
+    /**
+     * uploads an image
+     * 
+     * @param petId ID of pet to update 
+     * @param additionalMetadata Additional data to pass to server (optional)
+     * @param file file to upload (optional)
+     */
+    fun uploadFile(ctx: Context) {
+        val result = service.uploadFile(ctx.pathParamAsClass<kotlin.Long>("petId").get(), ctx.formParam("additionalMetadata"), ctx.uploadedFile("file"), ctx)
+        ctx.status(200).json(result)
+    }
+
+}

samples/server/petstore/kotlin-server/javalin-6/src/main/kotlin/org/openapitools/server/apis/PetApiService.kt

@@ -0,0 +1,112 @@
+package org.openapitools.server.apis
+
+import org.openapitools.server.models.ModelApiResponse
+import org.openapitools.server.models.Pet
+import io.javalin.http.Context
+
+interface PetApiService {
+
+    /**
+     * POST /pet : Add a new pet to the store
+     * 
+     *
+     * @param pet Pet object that needs to be added to the store (required)
+     * @param ctx The Javalin context. Especially handy if you need to access things like authentication headers in your service. (required)
+     * @return successful operation (status code 200)
+     *         or Invalid input (status code 405)
+     * @see PetApi#addPet
+     */
+    fun addPet(pet: Pet, ctx: Context): Pet
+
+    /**
+     * DELETE /pet/{petId} : Deletes a pet
+     * 
+     *
+     * @param petId Pet id to delete (required)
+     * @param apiKey  (optional)
+     * @param ctx The Javalin context. Especially handy if you need to access things like authentication headers in your service. (required)
+     * @return Invalid pet value (status code 400)
+     * @see PetApi#deletePet
+     */
+    fun deletePet(petId: kotlin.Long, apiKey: kotlin.String?, ctx: Context): Unit
+
+    /**
+     * GET /pet/findByStatus : Finds Pets by status
+     * Multiple status values can be provided with comma separated strings
+     *
+     * @param status Status values that need to be considered for filter (required)
+     * @param ctx The Javalin context. Especially handy if you need to access things like authentication headers in your service. (required)
+     * @return successful operation (status code 200)
+     *         or Invalid status value (status code 400)
+     * @see PetApi#findPetsByStatus
+     */
+    fun findPetsByStatus(status: kotlin.collections.List<kotlin.String>, ctx: Context): List<Pet>
+
+    /**
+     * GET /pet/findByTags : Finds Pets by tags
+     * Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
+     *
+     * @param tags Tags to filter by (required)
+     * @param ctx The Javalin context. Especially handy if you need to access things like authentication headers in your service. (required)
+     * @return successful operation (status code 200)
+     *         or Invalid tag value (status code 400)
+     * @deprecated
+     * @see PetApi#findPetsByTags
+     */
+    fun findPetsByTags(tags: kotlin.collections.List<kotlin.String>, ctx: Context): List<Pet>
+
+    /**
+     * GET /pet/{petId} : Find pet by ID
+     * Returns a single pet
+     *
+     * @param petId ID of pet to return (required)
+     * @param ctx The Javalin context. Especially handy if you need to access things like authentication headers in your service. (required)
+     * @return successful operation (status code 200)
+     *         or Invalid ID supplied (status code 400)
+     *         or Pet not found (status code 404)
+     * @see PetApi#getPetById
+     */
+    fun getPetById(petId: kotlin.Long, ctx: Context): Pet
+
+    /**
+     * PUT /pet : Update an existing pet
+     * 
+     *
+     * @param pet Pet object that needs to be added to the store (required)
+     * @param ctx The Javalin context. Especially handy if you need to access things like authentication headers in your service. (required)
+     * @return successful operation (status code 200)
+     *         or Invalid ID supplied (status code 400)
+     *         or Pet not found (status code 404)
+     *         or Validation exception (status code 405)
+     * API documentation for the updatePet operation
+     * @see <a href="http://petstore.swagger.io/v2/doc/updatePet">Update an existing pet Documentation</a>
+     * @see PetApi#updatePet
+     */
+    fun updatePet(pet: Pet, ctx: Context): Pet
+
+    /**
+     * POST /pet/{petId} : Updates a pet in the store with form data
+     * 
+     *
+     * @param petId ID of pet that needs to be updated (required)
+     * @param name Updated name of the pet (optional)
+     * @param status Updated status of the pet (optional)
+     * @param ctx The Javalin context. Especially handy if you need to access things like authentication headers in your service. (required)
+     * @return Invalid input (status code 405)
+     * @see PetApi#updatePetWithForm
+     */
+    fun updatePetWithForm(petId: kotlin.Long, name: kotlin.String?, status: kotlin.String?, ctx: Context): Unit
+
+    /**
+     * POST /pet/{petId}/uploadImage : uploads an image
+     * 
+     *
+     * @param petId ID of pet to update (required)
+     * @param additionalMetadata Additional data to pass to server (optional)
+     * @param file file to upload (optional)
+     * @param ctx The Javalin context. Especially handy if you need to access things like authentication headers in your service. (required)
+     * @return successful operation (status code 200)
+     * @see PetApi#uploadFile
+     */
+    fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String?, file: io.javalin.http.UploadedFile?, ctx: Context): ModelApiResponse
+}

samples/server/petstore/kotlin-server/javalin-6/src/main/kotlin/org/openapitools/server/apis/PetApiServiceImpl.kt

@@ -0,0 +1,40 @@
+package org.openapitools.server.apis
+
+import org.openapitools.server.models.ModelApiResponse
+import org.openapitools.server.models.Pet
+import io.javalin.http.Context
+
+class PetApiServiceImpl : PetApiService {
+
+    override fun addPet(pet: Pet, ctx: Context): Pet {
+        TODO("Implement me")
+    }
+
+    override fun deletePet(petId: kotlin.Long, apiKey: kotlin.String?, ctx: Context): Unit {
+        TODO("Implement me")
+    }
+
+    override fun findPetsByStatus(status: kotlin.collections.List<kotlin.String>, ctx: Context): List<Pet> {
+        TODO("Implement me")
+    }
+
+    override fun findPetsByTags(tags: kotlin.collections.List<kotlin.String>, ctx: Context): List<Pet> {
+        TODO("Implement me")
+    }
+
+    override fun getPetById(petId: kotlin.Long, ctx: Context): Pet {
+        TODO("Implement me")
+    }
+
+    override fun updatePet(pet: Pet, ctx: Context): Pet {
+        TODO("Implement me")
+    }
+
+    override fun updatePetWithForm(petId: kotlin.Long, name: kotlin.String?, status: kotlin.String?, ctx: Context): Unit {
+        TODO("Implement me")
+    }
+
+    override fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String?, file: io.javalin.http.UploadedFile?, ctx: Context): ModelApiResponse {
+        TODO("Implement me")
+    }
+}

samples/server/petstore/kotlin-server/javalin-6/src/main/kotlin/org/openapitools/server/apis/StoreApi.kt

@@ -0,0 +1,50 @@
+package org.openapitools.server.apis
+
+import io.javalin.http.Context
+import io.javalin.http.bodyAsClass
+import io.javalin.http.pathParamAsClass
+import io.javalin.http.queryParamAsClass
+
+import org.openapitools.server.models.Order
+
+class StoreApi(private val service: StoreApiService) {
+    /**
+     * Delete purchase order by ID
+     * For valid response try integer IDs with value < 1000. Anything above 1000 or nonintegers will generate API errors
+     * @param orderId ID of the order that needs to be deleted 
+     */
+    fun deleteOrder(ctx: Context) {
+        val result = service.deleteOrder(ctx.pathParamAsClass<kotlin.String>("orderId").get(), ctx)
+        ctx.status(400).json(result)
+    }
+
+    /**
+     * Returns pet inventories by status
+     * Returns a map of status codes to quantities
+     */
+    fun getInventory(ctx: Context) {
+        val result = service.getInventory(ctx)
+        ctx.status(200).json(result)
+    }
+
+    /**
+     * Find purchase order by ID
+     * For valid response try integer IDs with value &lt;&#x3D; 5 or &gt; 10. Other values will generate exceptions
+     * @param orderId ID of pet that needs to be fetched 
+     */
+    fun getOrderById(ctx: Context) {
+        val result = service.getOrderById(ctx.pathParamAsClass<kotlin.Long>("orderId").get(), ctx)
+        ctx.status(200).json(result)
+    }
+
+    /**
+     * Place an order for a pet
+     * 
+     * @param order order placed for purchasing the pet 
+     */
+    fun placeOrder(ctx: Context) {
+        val result = service.placeOrder(ctx.bodyAsClass<Order>(), ctx)
+        ctx.status(200).json(result)
+    }
+
+}

samples/server/petstore/kotlin-server/javalin-6/src/main/kotlin/org/openapitools/server/apis/StoreApiService.kt

@@ -0,0 +1,54 @@
+package org.openapitools.server.apis
+
+import org.openapitools.server.models.Order
+import io.javalin.http.Context
+
+interface StoreApiService {
+
+    /**
+     * DELETE /store/order/{orderId} : Delete purchase order by ID
+     * For valid response try integer IDs with value < 1000. Anything above 1000 or nonintegers will generate API errors
+     *
+     * @param orderId ID of the order that needs to be deleted (required)
+     * @param ctx The Javalin context. Especially handy if you need to access things like authentication headers in your service. (required)
+     * @return Invalid ID supplied (status code 400)
+     *         or Order not found (status code 404)
+     * @see StoreApi#deleteOrder
+     */
+    fun deleteOrder(orderId: kotlin.String, ctx: Context): Unit
+
+    /**
+     * GET /store/inventory : Returns pet inventories by status
+     * Returns a map of status codes to quantities
+     *
+     * @param ctx The Javalin context. Especially handy if you need to access things like authentication headers in your service. (required)
+     * @return successful operation (status code 200)
+     * @see StoreApi#getInventory
+     */
+    fun getInventory(ctx: Context): Map<String, kotlin.Int>
+
+    /**
+     * GET /store/order/{orderId} : Find purchase order by ID
+     * For valid response try integer IDs with value &lt;&#x3D; 5 or &gt; 10. Other values will generate exceptions
+     *
+     * @param orderId ID of pet that needs to be fetched (required)
+     * @param ctx The Javalin context. Especially handy if you need to access things like authentication headers in your service. (required)
+     * @return successful operation (status code 200)
+     *         or Invalid ID supplied (status code 400)
+     *         or Order not found (status code 404)
+     * @see StoreApi#getOrderById
+     */
+    fun getOrderById(orderId: kotlin.Long, ctx: Context): Order
+
+    /**
+     * POST /store/order : Place an order for a pet
+     * 
+     *
+     * @param order order placed for purchasing the pet (required)
+     * @param ctx The Javalin context. Especially handy if you need to access things like authentication headers in your service. (required)
+     * @return successful operation (status code 200)
+     *         or Invalid Order (status code 400)
+     * @see StoreApi#placeOrder
+     */
+    fun placeOrder(order: Order, ctx: Context): Order
+}

samples/server/petstore/kotlin-server/javalin-6/src/main/kotlin/org/openapitools/server/apis/StoreApiServiceImpl.kt

@@ -0,0 +1,23 @@
+package org.openapitools.server.apis
+
+import org.openapitools.server.models.Order
+import io.javalin.http.Context
+
+class StoreApiServiceImpl : StoreApiService {
+
+    override fun deleteOrder(orderId: kotlin.String, ctx: Context): Unit {
+        TODO("Implement me")
+    }
+
+    override fun getInventory(ctx: Context): Map<String, kotlin.Int> {
+        TODO("Implement me")
+    }
+
+    override fun getOrderById(orderId: kotlin.Long, ctx: Context): Order {
+        TODO("Implement me")
+    }
+
+    override fun placeOrder(order: Order, ctx: Context): Order {
+        TODO("Implement me")
+    }
+}

samples/server/petstore/kotlin-server/javalin-6/src/main/kotlin/org/openapitools/server/apis/UserApi.kt

@@ -0,0 +1,92 @@
+package org.openapitools.server.apis
+
+import io.javalin.http.Context
+import io.javalin.http.bodyAsClass
+import io.javalin.http.pathParamAsClass
+import io.javalin.http.queryParamAsClass
+
+import org.openapitools.server.models.User
+
+class UserApi(private val service: UserApiService) {
+    /**
+     * Create user
+     * This can only be done by the logged in user.
+     * @param user Created user object 
+     */
+    fun createUser(ctx: Context) {
+        val result = service.createUser(ctx.bodyAsClass<User>(), ctx)
+        ctx.status(200).json(result)
+    }
+
+    /**
+     * Creates list of users with given input array
+     * 
+     * @param user List of user object 
+     */
+    fun createUsersWithArrayInput(ctx: Context) {
+        val result = service.createUsersWithArrayInput(ctx.bodyAsClass<List<User>>(), ctx)
+        ctx.status(200).json(result)
+    }
+
+    /**
+     * Creates list of users with given input array
+     * 
+     * @param user List of user object 
+     */
+    fun createUsersWithListInput(ctx: Context) {
+        val result = service.createUsersWithListInput(ctx.bodyAsClass<List<User>>(), ctx)
+        ctx.status(200).json(result)
+    }
+
+    /**
+     * Delete user
+     * This can only be done by the logged in user.
+     * @param username The name that needs to be deleted 
+     */
+    fun deleteUser(ctx: Context) {
+        val result = service.deleteUser(ctx.pathParamAsClass<kotlin.String>("username").get(), ctx)
+        ctx.status(400).json(result)
+    }
+
+    /**
+     * Get user by user name
+     * 
+     * @param username The name that needs to be fetched. Use user1 for testing. 
+     */
+    fun getUserByName(ctx: Context) {
+        val result = service.getUserByName(ctx.pathParamAsClass<kotlin.String>("username").get(), ctx)
+        ctx.status(200).json(result)
+    }
+
+    /**
+     * Logs user into the system
+     * 
+     * @param username The user name for login 
+     * @param password The password for login in clear text 
+     */
+    fun loginUser(ctx: Context) {
+        val result = service.loginUser(ctx.queryParamAsClass<kotlin.String>("username").get(), ctx.queryParamAsClass<kotlin.String>("password").get(), ctx)
+        ctx.status(200).json(result)
+    }
+
+    /**
+     * Logs out current logged in user session
+     * 
+     */
+    fun logoutUser(ctx: Context) {
+        val result = service.logoutUser(ctx)
+        ctx.status(200).json(result)
+    }
+
+    /**
+     * Updated user
+     * This can only be done by the logged in user.
+     * @param username name that need to be deleted 
+     * @param user Updated user object 
+     */
+    fun updateUser(ctx: Context) {
+        val result = service.updateUser(ctx.pathParamAsClass<kotlin.String>("username").get(), ctx.bodyAsClass<User>(), ctx)
+        ctx.status(400).json(result)
+    }
+
+}

samples/server/petstore/kotlin-server/javalin-6/src/main/kotlin/org/openapitools/server/apis/UserApiService.kt

@@ -0,0 +1,101 @@
+package org.openapitools.server.apis
+
+import org.openapitools.server.models.User
+import io.javalin.http.Context
+
+interface UserApiService {
+
+    /**
+     * POST /user : Create user
+     * This can only be done by the logged in user.
+     *
+     * @param user Created user object (required)
+     * @param ctx The Javalin context. Especially handy if you need to access things like authentication headers in your service. (required)
+     * @return successful operation (status code 200)
+     * @see UserApi#createUser
+     */
+    fun createUser(user: User, ctx: Context): Unit
+
+    /**
+     * POST /user/createWithArray : Creates list of users with given input array
+     * 
+     *
+     * @param user List of user object (required)
+     * @param ctx The Javalin context. Especially handy if you need to access things like authentication headers in your service. (required)
+     * @return successful operation (status code 200)
+     * @see UserApi#createUsersWithArrayInput
+     */
+    fun createUsersWithArrayInput(user: kotlin.collections.List<User>, ctx: Context): Unit
+
+    /**
+     * POST /user/createWithList : Creates list of users with given input array
+     * 
+     *
+     * @param user List of user object (required)
+     * @param ctx The Javalin context. Especially handy if you need to access things like authentication headers in your service. (required)
+     * @return successful operation (status code 200)
+     * @see UserApi#createUsersWithListInput
+     */
+    fun createUsersWithListInput(user: kotlin.collections.List<User>, ctx: Context): Unit
+
+    /**
+     * DELETE /user/{username} : Delete user
+     * This can only be done by the logged in user.
+     *
+     * @param username The name that needs to be deleted (required)
+     * @param ctx The Javalin context. Especially handy if you need to access things like authentication headers in your service. (required)
+     * @return Invalid username supplied (status code 400)
+     *         or User not found (status code 404)
+     * @see UserApi#deleteUser
+     */
+    fun deleteUser(username: kotlin.String, ctx: Context): Unit
+
+    /**
+     * GET /user/{username} : Get user by user name
+     * 
+     *
+     * @param username The name that needs to be fetched. Use user1 for testing. (required)
+     * @param ctx The Javalin context. Especially handy if you need to access things like authentication headers in your service. (required)
+     * @return successful operation (status code 200)
+     *         or Invalid username supplied (status code 400)
+     *         or User not found (status code 404)
+     * @see UserApi#getUserByName
+     */
+    fun getUserByName(username: kotlin.String, ctx: Context): User
+
+    /**
+     * GET /user/login : Logs user into the system
+     * 
+     *
+     * @param username The user name for login (required)
+     * @param password The password for login in clear text (required)
+     * @param ctx The Javalin context. Especially handy if you need to access things like authentication headers in your service. (required)
+     * @return successful operation (status code 200)
+     *         or Invalid username/password supplied (status code 400)
+     * @see UserApi#loginUser
+     */
+    fun loginUser(username: kotlin.String, password: kotlin.String, ctx: Context): kotlin.String
+
+    /**
+     * GET /user/logout : Logs out current logged in user session
+     * 
+     *
+     * @param ctx The Javalin context. Especially handy if you need to access things like authentication headers in your service. (required)
+     * @return successful operation (status code 200)
+     * @see UserApi#logoutUser
+     */
+    fun logoutUser(ctx: Context): Unit
+
+    /**
+     * PUT /user/{username} : Updated user
+     * This can only be done by the logged in user.
+     *
+     * @param username name that need to be deleted (required)
+     * @param user Updated user object (required)
+     * @param ctx The Javalin context. Especially handy if you need to access things like authentication headers in your service. (required)
+     * @return Invalid user supplied (status code 400)
+     *         or User not found (status code 404)
+     * @see UserApi#updateUser
+     */
+    fun updateUser(username: kotlin.String, user: User, ctx: Context): Unit
+}

samples/server/petstore/kotlin-server/javalin-6/src/main/kotlin/org/openapitools/server/apis/UserApiServiceImpl.kt

@@ -0,0 +1,39 @@
+package org.openapitools.server.apis
+
+import org.openapitools.server.models.User
+import io.javalin.http.Context
+
+class UserApiServiceImpl : UserApiService {
+
+    override fun createUser(user: User, ctx: Context): Unit {
+        TODO("Implement me")
+    }
+
+    override fun createUsersWithArrayInput(user: kotlin.collections.List<User>, ctx: Context): Unit {
+        TODO("Implement me")
+    }
+
+    override fun createUsersWithListInput(user: kotlin.collections.List<User>, ctx: Context): Unit {
+        TODO("Implement me")
+    }
+
+    override fun deleteUser(username: kotlin.String, ctx: Context): Unit {
+        TODO("Implement me")
+    }
+
+    override fun getUserByName(username: kotlin.String, ctx: Context): User {
+        TODO("Implement me")
+    }
+
+    override fun loginUser(username: kotlin.String, password: kotlin.String, ctx: Context): kotlin.String {
+        TODO("Implement me")
+    }
+
+    override fun logoutUser(ctx: Context): Unit {
+        TODO("Implement me")
+    }
+
+    override fun updateUser(username: kotlin.String, user: User, ctx: Context): Unit {
+        TODO("Implement me")
+    }
+}

samples/server/petstore/kotlin-server/javalin-6/src/main/kotlin/org/openapitools/server/models/Category.kt

@@ -0,0 +1,24 @@
+/**
+ * OpenAPI Petstore
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+*/
+package org.openapitools.server.models
+
+
+/**
+ * A category for a pet
+ * @param id 
+ * @param name 
+ */
+data class Category(
+    val id: kotlin.Long? = null,
+    val name: kotlin.String? = null
+) 
+

samples/server/petstore/kotlin-server/javalin-6/src/main/kotlin/org/openapitools/server/models/ModelApiResponse.kt

@@ -0,0 +1,26 @@
+/**
+ * OpenAPI Petstore
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+*/
+package org.openapitools.server.models
+
+
+/**
+ * Describes the result of uploading an image resource
+ * @param code 
+ * @param type 
+ * @param message 
+ */
+data class ModelApiResponse(
+    val code: kotlin.Int? = null,
+    val type: kotlin.String? = null,
+    val message: kotlin.String? = null
+) 
+

samples/server/petstore/kotlin-server/javalin-6/src/main/kotlin/org/openapitools/server/models/Order.kt

@@ -0,0 +1,44 @@
+/**
+ * OpenAPI Petstore
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+*/
+package org.openapitools.server.models
+
+
+/**
+ * An order for a pets from the pet store
+ * @param id 
+ * @param petId 
+ * @param quantity 
+ * @param shipDate 
+ * @param status Order Status
+ * @param complete 
+ */
+data class Order(
+    val id: kotlin.Long? = null,
+    val petId: kotlin.Long? = null,
+    val quantity: kotlin.Int? = null,
+    val shipDate: java.time.OffsetDateTime? = null,
+    /* Order Status */
+    val status: Order.Status? = null,
+    val complete: kotlin.Boolean? = false
+) 
+{
+    /**
+    * Order Status
+    * Values: placed,approved,delivered
+    */
+    enum class Status(val value: kotlin.String){
+        placed("placed"),
+        approved("approved"),
+        delivered("delivered");
+    }
+}
+

samples/server/petstore/kotlin-server/javalin-6/src/main/kotlin/org/openapitools/server/models/Pet.kt

@@ -0,0 +1,46 @@
+/**
+ * OpenAPI Petstore
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+*/
+package org.openapitools.server.models
+
+import org.openapitools.server.models.Category
+import org.openapitools.server.models.Tag
+
+/**
+ * A pet for sale in the pet store
+ * @param name 
+ * @param photoUrls 
+ * @param id 
+ * @param category 
+ * @param tags 
+ * @param status pet status in the store
+ */
+data class Pet(
+    val name: kotlin.String,
+    val photoUrls: kotlin.collections.List<kotlin.String>,
+    val id: kotlin.Long? = null,
+    val category: Category? = null,
+    val tags: kotlin.collections.List<Tag>? = null,
+    /* pet status in the store */
+    val status: Pet.Status? = null
+) 
+{
+    /**
+    * pet status in the store
+    * Values: available,pending,sold
+    */
+    enum class Status(val value: kotlin.String){
+        available("available"),
+        pending("pending"),
+        sold("sold");
+    }
+}
+

samples/server/petstore/kotlin-server/javalin-6/src/main/kotlin/org/openapitools/server/models/Tag.kt

@@ -0,0 +1,24 @@
+/**
+ * OpenAPI Petstore
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+*/
+package org.openapitools.server.models
+
+
+/**
+ * A tag for a pet
+ * @param id 
+ * @param name 
+ */
+data class Tag(
+    val id: kotlin.Long? = null,
+    val name: kotlin.String? = null
+) 
+

samples/server/petstore/kotlin-server/javalin-6/src/main/kotlin/org/openapitools/server/models/User.kt

@@ -0,0 +1,37 @@
+/**
+ * OpenAPI Petstore
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+*/
+package org.openapitools.server.models
+
+
+/**
+ * A User who is purchasing from the pet store
+ * @param id 
+ * @param username 
+ * @param firstName 
+ * @param lastName 
+ * @param email 
+ * @param password 
+ * @param phone 
+ * @param userStatus User Status
+ */
+data class User(
+    val id: kotlin.Long? = null,
+    val username: kotlin.String? = null,
+    val firstName: kotlin.String? = null,
+    val lastName: kotlin.String? = null,
+    val email: kotlin.String? = null,
+    val password: kotlin.String? = null,
+    val phone: kotlin.String? = null,
+    /* User Status */
+    val userStatus: kotlin.Int? = null
+) 
+