diff --git a/modules/openapi-generator/src/main/resources/kotlin-client/api.mustache b/modules/openapi-generator/src/main/resources/kotlin-client/api.mustache
index 0d1b2642091..46319b16e83 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-client/api.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-client/api.mustache
@@ -25,8 +25,12 @@ import {{packageName}}.infrastructure.toMultiValue
     * {{notes}}
     {{#allParams}}* @param {{paramName}} {{description}} {{^required}}(optional{{#defaultValue}}, default to {{{.}}}{{/defaultValue}}){{/required}}
     {{/allParams}}* @return {{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}void{{/returnType}}
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */{{#returnType}}
     @Suppress("UNCHECKED_CAST"){{/returnType}}
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun {{operationId}}({{#allParams}}{{paramName}}: {{{dataType}}}{{^required}}?{{/required}}{{#hasMore}}, {{/hasMore}}{{/allParams}}) : {{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}Unit{{/returnType}} {
         val localVariableBody: kotlin.Any? = {{#hasBodyParam}}{{#bodyParams}}{{paramName}}{{/bodyParams}}{{/hasBodyParam}}{{^hasBodyParam}}{{^hasFormParams}}null{{/hasFormParams}}{{#hasFormParams}}mapOf({{#formParams}}"{{{baseName}}}" to "${{paramName}}"{{#hasMore}}, {{/hasMore}}{{/formParams}}){{/hasFormParams}}{{/hasBodyParam}}
         val localVariableQuery: MultiValueMap = {{^hasQueryParams}}mutableMapOf()
diff --git a/samples/client/petstore/kotlin-nonpublic/.openapi-generator/VERSION b/samples/client/petstore/kotlin-nonpublic/.openapi-generator/VERSION
index c3a2c7076fa..d168f1d8bda 100644
--- a/samples/client/petstore/kotlin-nonpublic/.openapi-generator/VERSION
+++ b/samples/client/petstore/kotlin-nonpublic/.openapi-generator/VERSION
@@ -1 +1 @@
-4.2.0-SNAPSHOT
\ No newline at end of file
+4.2.1-SNAPSHOT
\ No newline at end of file
diff --git a/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/PetApi.kt b/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
index c45cb1bdfb2..edce99a2128 100644
--- a/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
+++ b/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
@@ -33,7 +33,11 @@ internal class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2")
     * 
     * @param body Pet object that needs to be added to the store 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun addPet(body: Pet) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -64,7 +68,11 @@ internal class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2")
     * @param petId Pet id to delete 
     * @param apiKey  (optional)
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun deletePet(petId: kotlin.Long, apiKey: kotlin.String?) : Unit {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -94,8 +102,12 @@ internal class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2")
     * Multiple status values can be provided with comma separated strings
     * @param status Status values that need to be considered for filter 
     * @return kotlin.Array<Pet>
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun findPetsByStatus(status: kotlin.Array<kotlin.String>) : kotlin.Array<Pet> {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf<kotlin.String, List<kotlin.String>>()
@@ -128,8 +140,12 @@ internal class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2")
     * Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
     * @param tags Tags to filter by 
     * @return kotlin.Array<Pet>
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun findPetsByTags(tags: kotlin.Array<kotlin.String>) : kotlin.Array<Pet> {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf<kotlin.String, List<kotlin.String>>()
@@ -162,8 +178,12 @@ internal class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2")
     * Returns a single pet
     * @param petId ID of pet to return 
     * @return Pet
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun getPetById(petId: kotlin.Long) : Pet {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -193,7 +213,11 @@ internal class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2")
     * 
     * @param body Pet object that needs to be added to the store 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun updatePet(body: Pet) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -225,7 +249,11 @@ internal class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2")
     * @param name Updated name of the pet (optional)
     * @param status Updated status of the pet (optional)
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun updatePetWithForm(petId: kotlin.Long, name: kotlin.String?, status: kotlin.String?) : Unit {
         val localVariableBody: kotlin.Any? = mapOf("name" to "$name", "status" to "$status")
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -257,8 +285,12 @@ internal class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2")
     * @param additionalMetadata Additional data to pass to server (optional)
     * @param file file to upload (optional)
     * @return ApiResponse
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String?, file: java.io.File?) : ApiResponse {
         val localVariableBody: kotlin.Any? = mapOf("additionalMetadata" to "$additionalMetadata", "file" to "$file")
         val localVariableQuery: MultiValueMap = mutableMapOf()
diff --git a/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt b/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
index 8674aac2d62..46b6b316d95 100644
--- a/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
+++ b/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
@@ -32,7 +32,11 @@ internal class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2
     * For valid response try integer IDs with value &lt; 1000. Anything above 1000 or nonintegers will generate API errors
     * @param orderId ID of the order that needs to be deleted 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun deleteOrder(orderId: kotlin.String) : Unit {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -61,8 +65,12 @@ internal class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2
     * Returns pet inventories by status
     * Returns a map of status codes to quantities
     * @return kotlin.collections.Map<kotlin.String, kotlin.Int>
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun getInventory() : kotlin.collections.Map<kotlin.String, kotlin.Int> {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -92,8 +100,12 @@ internal class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2
     * For valid response try integer IDs with value &lt;&#x3D; 5 or &gt; 10. Other values will generated exceptions
     * @param orderId ID of pet that needs to be fetched 
     * @return Order
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun getOrderById(orderId: kotlin.Long) : Order {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -123,8 +135,12 @@ internal class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2
     * 
     * @param body order placed for purchasing the pet 
     * @return Order
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun placeOrder(body: Order) : Order {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
diff --git a/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/UserApi.kt b/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
index c83a633b739..4b289be0dcd 100644
--- a/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
+++ b/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
@@ -32,7 +32,11 @@ internal class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2"
     * This can only be done by the logged in user.
     * @param body Created user object 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun createUser(body: User) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -62,7 +66,11 @@ internal class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2"
     * 
     * @param body List of user object 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun createUsersWithArrayInput(body: kotlin.Array<User>) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -92,7 +100,11 @@ internal class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2"
     * 
     * @param body List of user object 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun createUsersWithListInput(body: kotlin.Array<User>) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -122,7 +134,11 @@ internal class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2"
     * This can only be done by the logged in user.
     * @param username The name that needs to be deleted 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun deleteUser(username: kotlin.String) : Unit {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -152,8 +168,12 @@ internal class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2"
     * 
     * @param username The name that needs to be fetched. Use user1 for testing. 
     * @return User
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun getUserByName(username: kotlin.String) : User {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -184,8 +204,12 @@ internal class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2"
     * @param username The user name for login 
     * @param password The password for login in clear text 
     * @return kotlin.String
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun loginUser(username: kotlin.String, password: kotlin.String) : kotlin.String {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf<kotlin.String, List<kotlin.String>>()
@@ -218,7 +242,11 @@ internal class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2"
     * Logs out current logged in user session
     * 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun logoutUser() : Unit {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -249,7 +277,11 @@ internal class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2"
     * @param username name that need to be deleted 
     * @param body Updated user object 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun updateUser(username: kotlin.String, body: User) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
diff --git a/samples/client/petstore/kotlin-okhttp3/.openapi-generator/VERSION b/samples/client/petstore/kotlin-okhttp3/.openapi-generator/VERSION
index c3a2c7076fa..d168f1d8bda 100644
--- a/samples/client/petstore/kotlin-okhttp3/.openapi-generator/VERSION
+++ b/samples/client/petstore/kotlin-okhttp3/.openapi-generator/VERSION
@@ -1 +1 @@
-4.2.0-SNAPSHOT
\ No newline at end of file
+4.2.1-SNAPSHOT
\ No newline at end of file
diff --git a/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/PetApi.kt b/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
index 00ca029e5a0..bc3e77dbf5f 100644
--- a/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
+++ b/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
@@ -33,7 +33,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * 
     * @param body Pet object that needs to be added to the store 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun addPet(body: Pet) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -64,7 +68,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * @param petId Pet id to delete 
     * @param apiKey  (optional)
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun deletePet(petId: kotlin.Long, apiKey: kotlin.String?) : Unit {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -94,8 +102,12 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * Multiple status values can be provided with comma separated strings
     * @param status Status values that need to be considered for filter 
     * @return kotlin.Array<Pet>
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun findPetsByStatus(status: kotlin.Array<kotlin.String>) : kotlin.Array<Pet> {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf<kotlin.String, List<kotlin.String>>()
@@ -128,8 +140,12 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
     * @param tags Tags to filter by 
     * @return kotlin.Array<Pet>
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun findPetsByTags(tags: kotlin.Array<kotlin.String>) : kotlin.Array<Pet> {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf<kotlin.String, List<kotlin.String>>()
@@ -162,8 +178,12 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * Returns a single pet
     * @param petId ID of pet to return 
     * @return Pet
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun getPetById(petId: kotlin.Long) : Pet {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -193,7 +213,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * 
     * @param body Pet object that needs to be added to the store 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun updatePet(body: Pet) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -225,7 +249,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * @param name Updated name of the pet (optional)
     * @param status Updated status of the pet (optional)
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun updatePetWithForm(petId: kotlin.Long, name: kotlin.String?, status: kotlin.String?) : Unit {
         val localVariableBody: kotlin.Any? = mapOf("name" to "$name", "status" to "$status")
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -257,8 +285,12 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * @param additionalMetadata Additional data to pass to server (optional)
     * @param file file to upload (optional)
     * @return ApiResponse
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String?, file: java.io.File?) : ApiResponse {
         val localVariableBody: kotlin.Any? = mapOf("additionalMetadata" to "$additionalMetadata", "file" to "$file")
         val localVariableQuery: MultiValueMap = mutableMapOf()
diff --git a/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt b/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
index a26e1096b3b..086f39cc5e7 100644
--- a/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
+++ b/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
@@ -32,7 +32,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
     * For valid response try integer IDs with value &lt; 1000. Anything above 1000 or nonintegers will generate API errors
     * @param orderId ID of the order that needs to be deleted 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun deleteOrder(orderId: kotlin.String) : Unit {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -61,8 +65,12 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
     * Returns pet inventories by status
     * Returns a map of status codes to quantities
     * @return kotlin.collections.Map<kotlin.String, kotlin.Int>
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun getInventory() : kotlin.collections.Map<kotlin.String, kotlin.Int> {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -92,8 +100,12 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
     * For valid response try integer IDs with value &lt;&#x3D; 5 or &gt; 10. Other values will generated exceptions
     * @param orderId ID of pet that needs to be fetched 
     * @return Order
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun getOrderById(orderId: kotlin.Long) : Order {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -123,8 +135,12 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
     * 
     * @param body order placed for purchasing the pet 
     * @return Order
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun placeOrder(body: Order) : Order {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
diff --git a/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/UserApi.kt b/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
index 180fd748722..0e22814d9de 100644
--- a/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
+++ b/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
@@ -32,7 +32,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * This can only be done by the logged in user.
     * @param body Created user object 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun createUser(body: User) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -62,7 +66,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * 
     * @param body List of user object 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun createUsersWithArrayInput(body: kotlin.Array<User>) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -92,7 +100,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * 
     * @param body List of user object 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun createUsersWithListInput(body: kotlin.Array<User>) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -122,7 +134,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * This can only be done by the logged in user.
     * @param username The name that needs to be deleted 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun deleteUser(username: kotlin.String) : Unit {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -152,8 +168,12 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * 
     * @param username The name that needs to be fetched. Use user1 for testing. 
     * @return User
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun getUserByName(username: kotlin.String) : User {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -184,8 +204,12 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * @param username The user name for login 
     * @param password The password for login in clear text 
     * @return kotlin.String
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun loginUser(username: kotlin.String, password: kotlin.String) : kotlin.String {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf<kotlin.String, List<kotlin.String>>()
@@ -218,7 +242,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * Logs out current logged in user session
     * 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun logoutUser() : Unit {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -249,7 +277,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * @param username name that need to be deleted 
     * @param body Updated user object 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun updateUser(username: kotlin.String, body: User) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
diff --git a/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/PetApi.kt b/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
index 00ca029e5a0..bc3e77dbf5f 100644
--- a/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
+++ b/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
@@ -33,7 +33,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * 
     * @param body Pet object that needs to be added to the store 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun addPet(body: Pet) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -64,7 +68,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * @param petId Pet id to delete 
     * @param apiKey  (optional)
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun deletePet(petId: kotlin.Long, apiKey: kotlin.String?) : Unit {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -94,8 +102,12 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * Multiple status values can be provided with comma separated strings
     * @param status Status values that need to be considered for filter 
     * @return kotlin.Array<Pet>
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun findPetsByStatus(status: kotlin.Array<kotlin.String>) : kotlin.Array<Pet> {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf<kotlin.String, List<kotlin.String>>()
@@ -128,8 +140,12 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
     * @param tags Tags to filter by 
     * @return kotlin.Array<Pet>
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun findPetsByTags(tags: kotlin.Array<kotlin.String>) : kotlin.Array<Pet> {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf<kotlin.String, List<kotlin.String>>()
@@ -162,8 +178,12 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * Returns a single pet
     * @param petId ID of pet to return 
     * @return Pet
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun getPetById(petId: kotlin.Long) : Pet {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -193,7 +213,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * 
     * @param body Pet object that needs to be added to the store 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun updatePet(body: Pet) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -225,7 +249,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * @param name Updated name of the pet (optional)
     * @param status Updated status of the pet (optional)
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun updatePetWithForm(petId: kotlin.Long, name: kotlin.String?, status: kotlin.String?) : Unit {
         val localVariableBody: kotlin.Any? = mapOf("name" to "$name", "status" to "$status")
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -257,8 +285,12 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * @param additionalMetadata Additional data to pass to server (optional)
     * @param file file to upload (optional)
     * @return ApiResponse
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String?, file: java.io.File?) : ApiResponse {
         val localVariableBody: kotlin.Any? = mapOf("additionalMetadata" to "$additionalMetadata", "file" to "$file")
         val localVariableQuery: MultiValueMap = mutableMapOf()
diff --git a/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt b/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
index a26e1096b3b..086f39cc5e7 100644
--- a/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
+++ b/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
@@ -32,7 +32,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
     * For valid response try integer IDs with value &lt; 1000. Anything above 1000 or nonintegers will generate API errors
     * @param orderId ID of the order that needs to be deleted 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun deleteOrder(orderId: kotlin.String) : Unit {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -61,8 +65,12 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
     * Returns pet inventories by status
     * Returns a map of status codes to quantities
     * @return kotlin.collections.Map<kotlin.String, kotlin.Int>
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun getInventory() : kotlin.collections.Map<kotlin.String, kotlin.Int> {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -92,8 +100,12 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
     * For valid response try integer IDs with value &lt;&#x3D; 5 or &gt; 10. Other values will generated exceptions
     * @param orderId ID of pet that needs to be fetched 
     * @return Order
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun getOrderById(orderId: kotlin.Long) : Order {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -123,8 +135,12 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
     * 
     * @param body order placed for purchasing the pet 
     * @return Order
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun placeOrder(body: Order) : Order {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
diff --git a/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/UserApi.kt b/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
index 180fd748722..0e22814d9de 100644
--- a/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
+++ b/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
@@ -32,7 +32,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * This can only be done by the logged in user.
     * @param body Created user object 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun createUser(body: User) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -62,7 +66,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * 
     * @param body List of user object 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun createUsersWithArrayInput(body: kotlin.Array<User>) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -92,7 +100,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * 
     * @param body List of user object 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun createUsersWithListInput(body: kotlin.Array<User>) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -122,7 +134,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * This can only be done by the logged in user.
     * @param username The name that needs to be deleted 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun deleteUser(username: kotlin.String) : Unit {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -152,8 +168,12 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * 
     * @param username The name that needs to be fetched. Use user1 for testing. 
     * @return User
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun getUserByName(username: kotlin.String) : User {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -184,8 +204,12 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * @param username The user name for login 
     * @param password The password for login in clear text 
     * @return kotlin.String
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun loginUser(username: kotlin.String, password: kotlin.String) : kotlin.String {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf<kotlin.String, List<kotlin.String>>()
@@ -218,7 +242,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * Logs out current logged in user session
     * 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun logoutUser() : Unit {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -249,7 +277,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * @param username name that need to be deleted 
     * @param body Updated user object 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun updateUser(username: kotlin.String, body: User) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
diff --git a/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/PetApi.kt b/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
index 00ca029e5a0..bc3e77dbf5f 100644
--- a/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
+++ b/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
@@ -33,7 +33,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * 
     * @param body Pet object that needs to be added to the store 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun addPet(body: Pet) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -64,7 +68,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * @param petId Pet id to delete 
     * @param apiKey  (optional)
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun deletePet(petId: kotlin.Long, apiKey: kotlin.String?) : Unit {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -94,8 +102,12 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * Multiple status values can be provided with comma separated strings
     * @param status Status values that need to be considered for filter 
     * @return kotlin.Array<Pet>
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun findPetsByStatus(status: kotlin.Array<kotlin.String>) : kotlin.Array<Pet> {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf<kotlin.String, List<kotlin.String>>()
@@ -128,8 +140,12 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
     * @param tags Tags to filter by 
     * @return kotlin.Array<Pet>
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun findPetsByTags(tags: kotlin.Array<kotlin.String>) : kotlin.Array<Pet> {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf<kotlin.String, List<kotlin.String>>()
@@ -162,8 +178,12 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * Returns a single pet
     * @param petId ID of pet to return 
     * @return Pet
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun getPetById(petId: kotlin.Long) : Pet {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -193,7 +213,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * 
     * @param body Pet object that needs to be added to the store 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun updatePet(body: Pet) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -225,7 +249,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * @param name Updated name of the pet (optional)
     * @param status Updated status of the pet (optional)
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun updatePetWithForm(petId: kotlin.Long, name: kotlin.String?, status: kotlin.String?) : Unit {
         val localVariableBody: kotlin.Any? = mapOf("name" to "$name", "status" to "$status")
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -257,8 +285,12 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * @param additionalMetadata Additional data to pass to server (optional)
     * @param file file to upload (optional)
     * @return ApiResponse
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String?, file: java.io.File?) : ApiResponse {
         val localVariableBody: kotlin.Any? = mapOf("additionalMetadata" to "$additionalMetadata", "file" to "$file")
         val localVariableQuery: MultiValueMap = mutableMapOf()
diff --git a/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt b/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
index a26e1096b3b..086f39cc5e7 100644
--- a/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
+++ b/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
@@ -32,7 +32,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
     * For valid response try integer IDs with value &lt; 1000. Anything above 1000 or nonintegers will generate API errors
     * @param orderId ID of the order that needs to be deleted 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun deleteOrder(orderId: kotlin.String) : Unit {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -61,8 +65,12 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
     * Returns pet inventories by status
     * Returns a map of status codes to quantities
     * @return kotlin.collections.Map<kotlin.String, kotlin.Int>
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun getInventory() : kotlin.collections.Map<kotlin.String, kotlin.Int> {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -92,8 +100,12 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
     * For valid response try integer IDs with value &lt;&#x3D; 5 or &gt; 10. Other values will generated exceptions
     * @param orderId ID of pet that needs to be fetched 
     * @return Order
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun getOrderById(orderId: kotlin.Long) : Order {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -123,8 +135,12 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
     * 
     * @param body order placed for purchasing the pet 
     * @return Order
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun placeOrder(body: Order) : Order {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
diff --git a/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/UserApi.kt b/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
index 180fd748722..0e22814d9de 100644
--- a/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
+++ b/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
@@ -32,7 +32,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * This can only be done by the logged in user.
     * @param body Created user object 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun createUser(body: User) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -62,7 +66,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * 
     * @param body List of user object 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun createUsersWithArrayInput(body: kotlin.Array<User>) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -92,7 +100,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * 
     * @param body List of user object 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun createUsersWithListInput(body: kotlin.Array<User>) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -122,7 +134,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * This can only be done by the logged in user.
     * @param username The name that needs to be deleted 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun deleteUser(username: kotlin.String) : Unit {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -152,8 +168,12 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * 
     * @param username The name that needs to be fetched. Use user1 for testing. 
     * @return User
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun getUserByName(username: kotlin.String) : User {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -184,8 +204,12 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * @param username The user name for login 
     * @param password The password for login in clear text 
     * @return kotlin.String
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun loginUser(username: kotlin.String, password: kotlin.String) : kotlin.String {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf<kotlin.String, List<kotlin.String>>()
@@ -218,7 +242,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * Logs out current logged in user session
     * 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun logoutUser() : Unit {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -249,7 +277,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * @param username name that need to be deleted 
     * @param body Updated user object 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun updateUser(username: kotlin.String, body: User) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
diff --git a/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/PetApi.kt b/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
index 00ca029e5a0..bc3e77dbf5f 100644
--- a/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
+++ b/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
@@ -33,7 +33,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * 
     * @param body Pet object that needs to be added to the store 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun addPet(body: Pet) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -64,7 +68,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * @param petId Pet id to delete 
     * @param apiKey  (optional)
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun deletePet(petId: kotlin.Long, apiKey: kotlin.String?) : Unit {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -94,8 +102,12 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * Multiple status values can be provided with comma separated strings
     * @param status Status values that need to be considered for filter 
     * @return kotlin.Array<Pet>
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun findPetsByStatus(status: kotlin.Array<kotlin.String>) : kotlin.Array<Pet> {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf<kotlin.String, List<kotlin.String>>()
@@ -128,8 +140,12 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
     * @param tags Tags to filter by 
     * @return kotlin.Array<Pet>
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun findPetsByTags(tags: kotlin.Array<kotlin.String>) : kotlin.Array<Pet> {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf<kotlin.String, List<kotlin.String>>()
@@ -162,8 +178,12 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * Returns a single pet
     * @param petId ID of pet to return 
     * @return Pet
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun getPetById(petId: kotlin.Long) : Pet {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -193,7 +213,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * 
     * @param body Pet object that needs to be added to the store 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun updatePet(body: Pet) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -225,7 +249,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * @param name Updated name of the pet (optional)
     * @param status Updated status of the pet (optional)
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun updatePetWithForm(petId: kotlin.Long, name: kotlin.String?, status: kotlin.String?) : Unit {
         val localVariableBody: kotlin.Any? = mapOf("name" to "$name", "status" to "$status")
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -257,8 +285,12 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
     * @param additionalMetadata Additional data to pass to server (optional)
     * @param file file to upload (optional)
     * @return ApiResponse
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun uploadFile(petId: kotlin.Long, additionalMetadata: kotlin.String?, file: java.io.File?) : ApiResponse {
         val localVariableBody: kotlin.Any? = mapOf("additionalMetadata" to "$additionalMetadata", "file" to "$file")
         val localVariableQuery: MultiValueMap = mutableMapOf()
diff --git a/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt b/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
index a26e1096b3b..086f39cc5e7 100644
--- a/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
+++ b/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
@@ -32,7 +32,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
     * For valid response try integer IDs with value &lt; 1000. Anything above 1000 or nonintegers will generate API errors
     * @param orderId ID of the order that needs to be deleted 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun deleteOrder(orderId: kotlin.String) : Unit {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -61,8 +65,12 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
     * Returns pet inventories by status
     * Returns a map of status codes to quantities
     * @return kotlin.collections.Map<kotlin.String, kotlin.Int>
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun getInventory() : kotlin.collections.Map<kotlin.String, kotlin.Int> {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -92,8 +100,12 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
     * For valid response try integer IDs with value &lt;&#x3D; 5 or &gt; 10. Other values will generated exceptions
     * @param orderId ID of pet that needs to be fetched 
     * @return Order
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun getOrderById(orderId: kotlin.Long) : Order {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -123,8 +135,12 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
     * 
     * @param body order placed for purchasing the pet 
     * @return Order
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun placeOrder(body: Order) : Order {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
diff --git a/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/UserApi.kt b/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
index 180fd748722..0e22814d9de 100644
--- a/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
+++ b/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
@@ -32,7 +32,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * This can only be done by the logged in user.
     * @param body Created user object 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun createUser(body: User) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -62,7 +66,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * 
     * @param body List of user object 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun createUsersWithArrayInput(body: kotlin.Array<User>) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -92,7 +100,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * 
     * @param body List of user object 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun createUsersWithListInput(body: kotlin.Array<User>) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -122,7 +134,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * This can only be done by the logged in user.
     * @param username The name that needs to be deleted 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun deleteUser(username: kotlin.String) : Unit {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -152,8 +168,12 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * 
     * @param username The name that needs to be fetched. Use user1 for testing. 
     * @return User
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun getUserByName(username: kotlin.String) : User {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -184,8 +204,12 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * @param username The user name for login 
     * @param password The password for login in clear text 
     * @return kotlin.String
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
     @Suppress("UNCHECKED_CAST")
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun loginUser(username: kotlin.String, password: kotlin.String) : kotlin.String {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf<kotlin.String, List<kotlin.String>>()
@@ -218,7 +242,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * Logs out current logged in user session
     * 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun logoutUser() : Unit {
         val localVariableBody: kotlin.Any? = null
         val localVariableQuery: MultiValueMap = mutableMapOf()
@@ -249,7 +277,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
     * @param username name that need to be deleted 
     * @param body Updated user object 
     * @return void
+    * @throws UnsupportedOperationException If the API returns an informational or redirection response
+    * @throws ClientException If the API returns a client error response
+    * @throws ServerException If the API returns a server error response
     */
+    @Throws(UnsupportedOperationException::class, ClientException::class, ServerException::class)
     fun updateUser(username: kotlin.String, body: User) : Unit {
         val localVariableBody: kotlin.Any? = body
         val localVariableQuery: MultiValueMap = mutableMapOf()