diff --git a/bin/utils/ensure-up-to-date b/bin/utils/ensure-up-to-date
index d950ce71e80..41dc4b9cd1a 100755
--- a/bin/utils/ensure-up-to-date
+++ b/bin/utils/ensure-up-to-date
@@ -24,6 +24,7 @@ declare -a scripts=(
 "./bin/kotlin-client-string.sh"
 "./bin/kotlin-client-threetenbp.sh"
 "./bin/kotlin-server-petstore.sh"
+"./bin/kotlin-springboot-petstore-server.sh"
 "./bin/mysql-schema-petstore.sh"
 "./bin/python-petstore-all.sh"
 "./bin/openapi3/python-petstore.sh"
diff --git a/bin/windows/kotlin-springboot-petstore-server.bat b/bin/windows/kotlin-springboot-petstore-server.bat
index 6b7e1ad6e77..4133a780d4a 100644
--- a/bin/windows/kotlin-springboot-petstore-server.bat
+++ b/bin/windows/kotlin-springboot-petstore-server.bat
@@ -1,10 +1,10 @@
-set executable=.\modules\openapi-generator-cli\target\openapi-generator-cli.jar
-
-If Not Exist %executable% (
-  mvn clean package
-)
-
-REM set JAVA_OPTS=%JAVA_OPTS% -Xmx1024M
-set ags=generate -i modules\openapi-generator\src\test\resources\2_0\petstore.yaml -g kotlin-spring -o samples\server\petstore\kotlin-springboot --additional-properties=library=spring-boot
-
-java %JAVA_OPTS% -jar %executable% %ags%
+set executable=.\modules\openapi-generator-cli\target\openapi-generator-cli.jar
+
+If Not Exist %executable% (
+  mvn clean package
+)
+
+REM set JAVA_OPTS=%JAVA_OPTS% -Xmx1024M
+set ags=generate -i modules\openapi-generator\src\test\resources\2_0\petstore.yaml -g kotlin-spring -o samples\server\petstore\kotlin-springboot --additional-properties=library=spring-boot,beanValidations=true,swaggerAnnotations=true,serviceImplementation=true
+
+java %JAVA_OPTS% -jar %executable% %ags%
diff --git a/modules/openapi-generator/src/main/resources/kotlin-spring/service.mustache b/modules/openapi-generator/src/main/resources/kotlin-spring/service.mustache
index 37892a1f534..12b073f7009 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-spring/service.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-spring/service.mustache
@@ -7,7 +7,7 @@ package {{package}}
 interface {{classname}}Service {
 {{#operation}}
 
-    fun {{operationId}}({{#allParams}}{{paramName}}: {{{dataType}}}{{#hasMore}},{{/hasMore}}{{/allParams}}): {{>returnTypes}}
+    fun {{operationId}}({{#allParams}}{{paramName}}: {{>optionalDataType}}{{#hasMore}}, {{/hasMore}}{{/allParams}}): {{>returnTypes}}
 {{/operation}}
 }
 {{/operations}}
diff --git a/modules/openapi-generator/src/main/resources/kotlin-spring/serviceImpl.mustache b/modules/openapi-generator/src/main/resources/kotlin-spring/serviceImpl.mustache
index 134600ecfc0..32e62866af2 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-spring/serviceImpl.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-spring/serviceImpl.mustache
@@ -8,7 +8,7 @@ import org.springframework.stereotype.Service
 class {{classname}}ServiceImpl : {{classname}}Service {
 {{#operation}}
 
-    override fun {{operationId}}({{#allParams}}{{paramName}}: {{{dataType}}}{{#hasMore}},{{/hasMore}}{{/allParams}}): {{>returnTypes}} {
+    override fun {{operationId}}({{#allParams}}{{paramName}}: {{>optionalDataType}}{{#hasMore}}, {{/hasMore}}{{/allParams}}): {{>returnTypes}} {
         TODO("Implement me")
     }
 {{/operation}}
diff --git a/samples/server/petstore/kotlin-springboot/src/main/kotlin/org/openapitools/api/PetApiService.kt b/samples/server/petstore/kotlin-springboot/src/main/kotlin/org/openapitools/api/PetApiService.kt
index 5218a25b638..741a97d8603 100644
--- a/samples/server/petstore/kotlin-springboot/src/main/kotlin/org/openapitools/api/PetApiService.kt
+++ b/samples/server/petstore/kotlin-springboot/src/main/kotlin/org/openapitools/api/PetApiService.kt
@@ -7,7 +7,7 @@ interface PetApiService {
 
     fun addPet(body: Pet): Unit
 
-    fun deletePet(petId: Long,apiKey: String): Unit
+    fun deletePet(petId: Long, apiKey: String?): Unit
 
     fun findPetsByStatus(status: List<String>): List<Pet>
 
@@ -17,7 +17,7 @@ interface PetApiService {
 
     fun updatePet(body: Pet): Unit
 
-    fun updatePetWithForm(petId: Long,name: String,status: String): Unit
+    fun updatePetWithForm(petId: Long, name: String?, status: String?): Unit
 
-    fun uploadFile(petId: Long,additionalMetadata: String,file: org.springframework.core.io.Resource): ModelApiResponse
+    fun uploadFile(petId: Long, additionalMetadata: String?, file: org.springframework.core.io.Resource?): ModelApiResponse
 }
diff --git a/samples/server/petstore/kotlin-springboot/src/main/kotlin/org/openapitools/api/PetApiServiceImpl.kt b/samples/server/petstore/kotlin-springboot/src/main/kotlin/org/openapitools/api/PetApiServiceImpl.kt
index 8de49b91daa..5ecf2c91f33 100644
--- a/samples/server/petstore/kotlin-springboot/src/main/kotlin/org/openapitools/api/PetApiServiceImpl.kt
+++ b/samples/server/petstore/kotlin-springboot/src/main/kotlin/org/openapitools/api/PetApiServiceImpl.kt
@@ -10,7 +10,7 @@ class PetApiServiceImpl : PetApiService {
         TODO("Implement me")
     }
 
-    override fun deletePet(petId: Long,apiKey: String): Unit {
+    override fun deletePet(petId: Long, apiKey: String?): Unit {
         TODO("Implement me")
     }
 
@@ -30,11 +30,11 @@ class PetApiServiceImpl : PetApiService {
         TODO("Implement me")
     }
 
-    override fun updatePetWithForm(petId: Long,name: String,status: String): Unit {
+    override fun updatePetWithForm(petId: Long, name: String?, status: String?): Unit {
         TODO("Implement me")
     }
 
-    override fun uploadFile(petId: Long,additionalMetadata: String,file: org.springframework.core.io.Resource): ModelApiResponse {
+    override fun uploadFile(petId: Long, additionalMetadata: String?, file: org.springframework.core.io.Resource?): ModelApiResponse {
         TODO("Implement me")
     }
 }
diff --git a/samples/server/petstore/kotlin-springboot/src/main/kotlin/org/openapitools/api/UserApiService.kt b/samples/server/petstore/kotlin-springboot/src/main/kotlin/org/openapitools/api/UserApiService.kt
index bdf37d33dc5..de61cf72c43 100644
--- a/samples/server/petstore/kotlin-springboot/src/main/kotlin/org/openapitools/api/UserApiService.kt
+++ b/samples/server/petstore/kotlin-springboot/src/main/kotlin/org/openapitools/api/UserApiService.kt
@@ -14,9 +14,9 @@ interface UserApiService {
 
     fun getUserByName(username: String): User
 
-    fun loginUser(username: String,password: String): String
+    fun loginUser(username: String, password: String): String
 
     fun logoutUser(): Unit
 
-    fun updateUser(username: String,body: User): Unit
+    fun updateUser(username: String, body: User): Unit
 }
diff --git a/samples/server/petstore/kotlin-springboot/src/main/kotlin/org/openapitools/api/UserApiServiceImpl.kt b/samples/server/petstore/kotlin-springboot/src/main/kotlin/org/openapitools/api/UserApiServiceImpl.kt
index da6787b8838..3373dcb6a73 100644
--- a/samples/server/petstore/kotlin-springboot/src/main/kotlin/org/openapitools/api/UserApiServiceImpl.kt
+++ b/samples/server/petstore/kotlin-springboot/src/main/kotlin/org/openapitools/api/UserApiServiceImpl.kt
@@ -25,7 +25,7 @@ class UserApiServiceImpl : UserApiService {
         TODO("Implement me")
     }
 
-    override fun loginUser(username: String,password: String): String {
+    override fun loginUser(username: String, password: String): String {
         TODO("Implement me")
     }
 
@@ -33,7 +33,7 @@ class UserApiServiceImpl : UserApiService {
         TODO("Implement me")
     }
 
-    override fun updateUser(username: String,body: User): Unit {
+    override fun updateUser(username: String, body: User): Unit {
         TODO("Implement me")
     }
 }