diff --git a/modules/swagger-codegen/src/main/resources/Java/api.mustache b/modules/swagger-codegen/src/main/resources/Java/api.mustache
index a1c9e05042d4..78bac41d9d6b 100644
--- a/modules/swagger-codegen/src/main/resources/Java/api.mustache
+++ b/modules/swagger-codegen/src/main/resources/Java/api.mustache
@@ -45,12 +45,12 @@ public class {{classname}} {
    */
   public {{#returnType}}{{{returnType}}} {{/returnType}}{{^returnType}}void {{/returnType}}{{nickname}} ({{#allParams}}{{{dataType}}} {{paramName}}{{#hasMore}}, {{/hasMore}}{{/allParams}}) throws ApiException {
     Object postBody = {{#bodyParam}}{{paramName}}{{/bodyParam}}{{^bodyParam}}null{{/bodyParam}};
-    {{#requiredParamCount}}
-    // verify required params are set
-    if({{/requiredParamCount}}{{#requiredParams}} {{paramName}} == null {{#hasMore}}|| {{/hasMore}}{{/requiredParams}}{{#requiredParamCount}}) {
-       throw new ApiException(400, "missing required params");
+    {{#allParams}}{{#required}}
+    // verify the required parameter '{{paramName}}' is set
+    if ({{paramName}} == null) {
+       throw new ApiException(400, "Missing the required parameter '{{paramName}}' when calling {{nickname}}");
     }
-    {{/requiredParamCount}}
+    {{/required}}{{/allParams}}
 
     // create path and map variables
     String path = "{{path}}".replaceAll("\\{format\\}","json"){{#pathParams}}
diff --git a/modules/swagger-codegen/src/main/resources/android-java/api.mustache b/modules/swagger-codegen/src/main/resources/android-java/api.mustache
index 0f21897e6779..ed9538c15941 100644
--- a/modules/swagger-codegen/src/main/resources/android-java/api.mustache
+++ b/modules/swagger-codegen/src/main/resources/android-java/api.mustache
@@ -47,13 +47,12 @@ public class {{classname}} {
    */
   public {{#returnType}}{{{returnType}}} {{/returnType}}{{^returnType}}void {{/returnType}} {{nickname}} ({{#allParams}}{{{dataType}}} {{paramName}}{{#hasMore}}, {{/hasMore}}{{/allParams}}) throws ApiException {
     Object postBody = {{#bodyParam}}{{paramName}}{{/bodyParam}}{{^bodyParam}}null{{/bodyParam}};
-
-    {{#requiredParamCount}}
-    // verify required params are set
-    if({{/requiredParamCount}}{{#requiredParams}} {{paramName}} == null {{#hasMore}}|| {{/hasMore}}{{/requiredParams}}{{#requiredParamCount}}) {
-       throw new ApiException(400, "missing required params");
+    {{#allParams}}{{#required}}
+    // verify the required parameter '{{paramName}}' is set
+    if ({{paramName}} == null) {
+       throw new ApiException(400, "Missing the required parameter '{{paramName}}' when calling {{nickname}}");
     }
-    {{/requiredParamCount}}
+    {{/required}}{{/allParams}}
 
     // create path and map variables
     String path = "{{path}}".replaceAll("\\{format\\}","json"){{#pathParams}}.replaceAll("\\{" + "{{paramName}}" + "\\}", apiInvoker.escapeString({{{paramName}}}.toString())){{/pathParams}};
diff --git a/modules/swagger-codegen/src/main/resources/php/api.mustache b/modules/swagger-codegen/src/main/resources/php/api.mustache
index a434699f90ad..e0b94e6b2325 100644
--- a/modules/swagger-codegen/src/main/resources/php/api.mustache
+++ b/modules/swagger-codegen/src/main/resources/php/api.mustache
@@ -39,6 +39,12 @@ class {{classname}} {
 {{/allParams}}   * @return {{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}void{{/returnType}}
    */
    public function {{nickname}}({{#allParams}}${{paramName}}{{#optional}}=null{{/optional}}{{#hasMore}}, {{/hasMore}}{{/allParams}}) {
+      {{#allParams}}{{#required}}
+      // verify the required parameter '{{paramName}}' is set
+      if (${{paramName}} === null) {
+        throw new \Exception("Missing the required parameter ${{paramName}} when calling {{nickname}}");
+      }
+      {{/required}}{{/allParams}}
 
       // parse inputs
       $resourcePath = "{{path}}";
diff --git a/modules/swagger-codegen/src/main/resources/ruby/api.mustache b/modules/swagger-codegen/src/main/resources/ruby/api.mustache
index 5b0d37322832..210c7d819bac 100644
--- a/modules/swagger-codegen/src/main/resources/ruby/api.mustache
+++ b/modules/swagger-codegen/src/main/resources/ruby/api.mustache
@@ -13,8 +13,10 @@ class {{classname}}
 {{#allParams}}{{^required}}  # @option opts [{{dataType}}] :{{paramName}} {{description}}
 {{/required}}{{/allParams}}  # @return {{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}void{{/returnType}}
   def self.{{nickname}}({{#allParams}}{{#required}}{{paramName}}, {{/required}}{{/allParams}}opts = {})
-    # verify existence of params{{#allParams}}{{#required}}
-    raise "{{{paramName}}} is required" if {{{paramName}}}.nil?{{/required}}{{/allParams}}
+    {{#allParams}}{{#required}}
+    # verify the required parameter '{{paramName}}' is set
+    raise "Missing the required parameter '{{paramName}}' when calling {{nickname}}" if {{{paramName}}}.nil?
+    {{/required}}{{/allParams}}
 
     # resource path
     path = "{{path}}".sub('{format}','json'){{#pathParams}}.sub('{' + '{{baseName}}' + '}', {{paramName}}.to_s){{/pathParams}}
diff --git a/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/PetApi.java b/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/PetApi.java
index c8da678b2f98..88fdfdb69808 100644
--- a/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/PetApi.java
+++ b/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/PetApi.java
@@ -46,7 +46,6 @@ public class PetApi {
    */
   public void  updatePet (Pet body) throws ApiException {
     Object postBody = body;
-
     
 
     // create path and map variables
@@ -101,7 +100,6 @@ public class PetApi {
    */
   public void  addPet (Pet body) throws ApiException {
     Object postBody = body;
-
     
 
     // create path and map variables
@@ -156,7 +154,6 @@ public class PetApi {
    */
   public List<Pet>  findPetsByStatus (List<String> status) throws ApiException {
     Object postBody = null;
-
     
 
     // create path and map variables
@@ -213,7 +210,6 @@ public class PetApi {
    */
   public List<Pet>  findPetsByTags (List<String> tags) throws ApiException {
     Object postBody = null;
-
     
 
     // create path and map variables
@@ -270,7 +266,11 @@ public class PetApi {
    */
   public Pet  getPetById (Long petId) throws ApiException {
     Object postBody = null;
-
+    
+    // verify the required parameter 'petId' is set
+    if (petId == null) {
+       throw new ApiException(400, "Missing the required parameter 'petId' when calling getPetById");
+    }
     
 
     // create path and map variables
@@ -327,7 +327,11 @@ public class PetApi {
    */
   public void  updatePetWithForm (String petId, String name, String status) throws ApiException {
     Object postBody = null;
-
+    
+    // verify the required parameter 'petId' is set
+    if (petId == null) {
+       throw new ApiException(400, "Missing the required parameter 'petId' when calling updatePetWithForm");
+    }
     
 
     // create path and map variables
@@ -393,7 +397,11 @@ public class PetApi {
    */
   public void  deletePet (String apiKey, Long petId) throws ApiException {
     Object postBody = null;
-
+    
+    // verify the required parameter 'petId' is set
+    if (petId == null) {
+       throw new ApiException(400, "Missing the required parameter 'petId' when calling deletePet");
+    }
     
 
     // create path and map variables
@@ -451,7 +459,11 @@ public class PetApi {
    */
   public void  uploadFile (Long petId, String additionalMetadata, File file) throws ApiException {
     Object postBody = null;
-
+    
+    // verify the required parameter 'petId' is set
+    if (petId == null) {
+       throw new ApiException(400, "Missing the required parameter 'petId' when calling uploadFile");
+    }
     
 
     // create path and map variables
diff --git a/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/StoreApi.java b/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/StoreApi.java
index 1e2ff3bba8a7..ecd8e8330490 100644
--- a/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/StoreApi.java
+++ b/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/StoreApi.java
@@ -45,7 +45,6 @@ public class StoreApi {
    */
   public Map<String, Integer>  getInventory () throws ApiException {
     Object postBody = null;
-
     
 
     // create path and map variables
@@ -100,7 +99,6 @@ public class StoreApi {
    */
   public Order  placeOrder (Order body) throws ApiException {
     Object postBody = body;
-
     
 
     // create path and map variables
@@ -155,7 +153,11 @@ public class StoreApi {
    */
   public Order  getOrderById (String orderId) throws ApiException {
     Object postBody = null;
-
+    
+    // verify the required parameter 'orderId' is set
+    if (orderId == null) {
+       throw new ApiException(400, "Missing the required parameter 'orderId' when calling getOrderById");
+    }
     
 
     // create path and map variables
@@ -210,7 +212,11 @@ public class StoreApi {
    */
   public void  deleteOrder (String orderId) throws ApiException {
     Object postBody = null;
-
+    
+    // verify the required parameter 'orderId' is set
+    if (orderId == null) {
+       throw new ApiException(400, "Missing the required parameter 'orderId' when calling deleteOrder");
+    }
     
 
     // create path and map variables
diff --git a/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/UserApi.java b/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/UserApi.java
index da105638c5f5..e1df3fd4f128 100644
--- a/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/UserApi.java
+++ b/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/UserApi.java
@@ -46,7 +46,6 @@ public class UserApi {
    */
   public void  createUser (User body) throws ApiException {
     Object postBody = body;
-
     
 
     // create path and map variables
@@ -101,7 +100,6 @@ public class UserApi {
    */
   public void  createUsersWithArrayInput (List<User> body) throws ApiException {
     Object postBody = body;
-
     
 
     // create path and map variables
@@ -156,7 +154,6 @@ public class UserApi {
    */
   public void  createUsersWithListInput (List<User> body) throws ApiException {
     Object postBody = body;
-
     
 
     // create path and map variables
@@ -212,7 +209,6 @@ public class UserApi {
    */
   public String  loginUser (String username, String password) throws ApiException {
     Object postBody = null;
-
     
 
     // create path and map variables
@@ -270,7 +266,6 @@ public class UserApi {
    */
   public void  logoutUser () throws ApiException {
     Object postBody = null;
-
     
 
     // create path and map variables
@@ -325,7 +320,11 @@ public class UserApi {
    */
   public User  getUserByName (String username) throws ApiException {
     Object postBody = null;
-
+    
+    // verify the required parameter 'username' is set
+    if (username == null) {
+       throw new ApiException(400, "Missing the required parameter 'username' when calling getUserByName");
+    }
     
 
     // create path and map variables
@@ -381,7 +380,11 @@ public class UserApi {
    */
   public void  updateUser (String username, User body) throws ApiException {
     Object postBody = body;
-
+    
+    // verify the required parameter 'username' is set
+    if (username == null) {
+       throw new ApiException(400, "Missing the required parameter 'username' when calling updateUser");
+    }
     
 
     // create path and map variables
@@ -436,7 +439,11 @@ public class UserApi {
    */
   public void  deleteUser (String username) throws ApiException {
     Object postBody = null;
-
+    
+    // verify the required parameter 'username' is set
+    if (username == null) {
+       throw new ApiException(400, "Missing the required parameter 'username' when calling deleteUser");
+    }
     
 
     // create path and map variables
diff --git a/samples/client/petstore/java/src/main/java/io/swagger/client/api/PetApi.java b/samples/client/petstore/java/src/main/java/io/swagger/client/api/PetApi.java
index 842c080024a8..b5d6bb70d79d 100644
--- a/samples/client/petstore/java/src/main/java/io/swagger/client/api/PetApi.java
+++ b/samples/client/petstore/java/src/main/java/io/swagger/client/api/PetApi.java
@@ -249,6 +249,11 @@ public class PetApi {
   public Pet getPetById (Long petId) throws ApiException {
     Object postBody = null;
     
+    // verify the required parameter 'petId' is set
+    if (petId == null) {
+       throw new ApiException(400, "Missing the required parameter 'petId' when calling getPetById");
+    }
+    
 
     // create path and map variables
     String path = "/pet/{petId}".replaceAll("\\{format\\}","json")
@@ -302,6 +307,11 @@ public class PetApi {
   public void updatePetWithForm (String petId, String name, String status) throws ApiException {
     Object postBody = null;
     
+    // verify the required parameter 'petId' is set
+    if (petId == null) {
+       throw new ApiException(400, "Missing the required parameter 'petId' when calling updatePetWithForm");
+    }
+    
 
     // create path and map variables
     String path = "/pet/{petId}".replaceAll("\\{format\\}","json")
@@ -362,6 +372,11 @@ public class PetApi {
   public void deletePet (String apiKey, Long petId) throws ApiException {
     Object postBody = null;
     
+    // verify the required parameter 'petId' is set
+    if (petId == null) {
+       throw new ApiException(400, "Missing the required parameter 'petId' when calling deletePet");
+    }
+    
 
     // create path and map variables
     String path = "/pet/{petId}".replaceAll("\\{format\\}","json")
@@ -416,6 +431,11 @@ public class PetApi {
   public void uploadFile (Long petId, String additionalMetadata, File file) throws ApiException {
     Object postBody = null;
     
+    // verify the required parameter 'petId' is set
+    if (petId == null) {
+       throw new ApiException(400, "Missing the required parameter 'petId' when calling uploadFile");
+    }
+    
 
     // create path and map variables
     String path = "/pet/{petId}/uploadImage".replaceAll("\\{format\\}","json")
diff --git a/samples/client/petstore/java/src/main/java/io/swagger/client/api/StoreApi.java b/samples/client/petstore/java/src/main/java/io/swagger/client/api/StoreApi.java
index cff340e69d7d..6da7b5abb2f2 100644
--- a/samples/client/petstore/java/src/main/java/io/swagger/client/api/StoreApi.java
+++ b/samples/client/petstore/java/src/main/java/io/swagger/client/api/StoreApi.java
@@ -144,6 +144,11 @@ public class StoreApi {
   public Order getOrderById (String orderId) throws ApiException {
     Object postBody = null;
     
+    // verify the required parameter 'orderId' is set
+    if (orderId == null) {
+       throw new ApiException(400, "Missing the required parameter 'orderId' when calling getOrderById");
+    }
+    
 
     // create path and map variables
     String path = "/store/order/{orderId}".replaceAll("\\{format\\}","json")
@@ -195,6 +200,11 @@ public class StoreApi {
   public void deleteOrder (String orderId) throws ApiException {
     Object postBody = null;
     
+    // verify the required parameter 'orderId' is set
+    if (orderId == null) {
+       throw new ApiException(400, "Missing the required parameter 'orderId' when calling deleteOrder");
+    }
+    
 
     // create path and map variables
     String path = "/store/order/{orderId}".replaceAll("\\{format\\}","json")
diff --git a/samples/client/petstore/java/src/main/java/io/swagger/client/api/UserApi.java b/samples/client/petstore/java/src/main/java/io/swagger/client/api/UserApi.java
index 2296c0223ce1..d0974d95a52b 100644
--- a/samples/client/petstore/java/src/main/java/io/swagger/client/api/UserApi.java
+++ b/samples/client/petstore/java/src/main/java/io/swagger/client/api/UserApi.java
@@ -299,6 +299,11 @@ public class UserApi {
   public User getUserByName (String username) throws ApiException {
     Object postBody = null;
     
+    // verify the required parameter 'username' is set
+    if (username == null) {
+       throw new ApiException(400, "Missing the required parameter 'username' when calling getUserByName");
+    }
+    
 
     // create path and map variables
     String path = "/user/{username}".replaceAll("\\{format\\}","json")
@@ -351,6 +356,11 @@ public class UserApi {
   public void updateUser (String username, User body) throws ApiException {
     Object postBody = body;
     
+    // verify the required parameter 'username' is set
+    if (username == null) {
+       throw new ApiException(400, "Missing the required parameter 'username' when calling updateUser");
+    }
+    
 
     // create path and map variables
     String path = "/user/{username}".replaceAll("\\{format\\}","json")
@@ -402,6 +412,11 @@ public class UserApi {
   public void deleteUser (String username) throws ApiException {
     Object postBody = null;
     
+    // verify the required parameter 'username' is set
+    if (username == null) {
+       throw new ApiException(400, "Missing the required parameter 'username' when calling deleteUser");
+    }
+    
 
     // create path and map variables
     String path = "/user/{username}".replaceAll("\\{format\\}","json")
diff --git a/samples/client/petstore/php/SwaggerClient-php/lib/PetApi.php b/samples/client/petstore/php/SwaggerClient-php/lib/PetApi.php
index 80d9c040d1ef..fc8331da4bd2 100644
--- a/samples/client/petstore/php/SwaggerClient-php/lib/PetApi.php
+++ b/samples/client/petstore/php/SwaggerClient-php/lib/PetApi.php
@@ -38,6 +38,7 @@ class PetApi {
    * @return void
    */
    public function updatePet($body) {
+      
 
       // parse inputs
       $resourcePath = "/pet";
@@ -91,6 +92,7 @@ class PetApi {
    * @return void
    */
    public function addPet($body) {
+      
 
       // parse inputs
       $resourcePath = "/pet";
@@ -144,6 +146,7 @@ class PetApi {
    * @return array[Pet]
    */
    public function findPetsByStatus($status) {
+      
 
       // parse inputs
       $resourcePath = "/pet/findByStatus";
@@ -202,6 +205,7 @@ class PetApi {
    * @return array[Pet]
    */
    public function findPetsByTags($tags) {
+      
 
       // parse inputs
       $resourcePath = "/pet/findByTags";
@@ -260,6 +264,12 @@ class PetApi {
    * @return Pet
    */
    public function getPetById($pet_id) {
+      
+      // verify the required parameter 'pet_id' is set
+      if ($pet_id === null) {
+        throw new \Exception("Missing the required parameter $pet_id when calling getPetById");
+      }
+      
 
       // parse inputs
       $resourcePath = "/pet/{petId}";
@@ -321,6 +331,12 @@ class PetApi {
    * @return void
    */
    public function updatePetWithForm($pet_id, $name, $status) {
+      
+      // verify the required parameter 'pet_id' is set
+      if ($pet_id === null) {
+        throw new \Exception("Missing the required parameter $pet_id when calling updatePetWithForm");
+      }
+      
 
       // parse inputs
       $resourcePath = "/pet/{petId}";
@@ -381,6 +397,12 @@ class PetApi {
    * @return void
    */
    public function deletePet($api_key, $pet_id) {
+      
+      // verify the required parameter 'pet_id' is set
+      if ($pet_id === null) {
+        throw new \Exception("Missing the required parameter $pet_id when calling deletePet");
+      }
+      
 
       // parse inputs
       $resourcePath = "/pet/{petId}";
@@ -439,6 +461,12 @@ class PetApi {
    * @return void
    */
    public function uploadFile($pet_id, $additional_metadata, $file) {
+      
+      // verify the required parameter 'pet_id' is set
+      if ($pet_id === null) {
+        throw new \Exception("Missing the required parameter $pet_id when calling uploadFile");
+      }
+      
 
       // parse inputs
       $resourcePath = "/pet/{petId}/uploadImage";
diff --git a/samples/client/petstore/php/SwaggerClient-php/lib/StoreApi.php b/samples/client/petstore/php/SwaggerClient-php/lib/StoreApi.php
index 4e40ed983b93..6e3ce56e7ced 100644
--- a/samples/client/petstore/php/SwaggerClient-php/lib/StoreApi.php
+++ b/samples/client/petstore/php/SwaggerClient-php/lib/StoreApi.php
@@ -37,6 +37,7 @@ class StoreApi {
    * @return map[string,int]
    */
    public function getInventory() {
+      
 
       // parse inputs
       $resourcePath = "/store/inventory";
@@ -92,6 +93,7 @@ class StoreApi {
    * @return Order
    */
    public function placeOrder($body) {
+      
 
       // parse inputs
       $resourcePath = "/store/order";
@@ -151,6 +153,12 @@ class StoreApi {
    * @return Order
    */
    public function getOrderById($order_id) {
+      
+      // verify the required parameter 'order_id' is set
+      if ($order_id === null) {
+        throw new \Exception("Missing the required parameter $order_id when calling getOrderById");
+      }
+      
 
       // parse inputs
       $resourcePath = "/store/order/{orderId}";
@@ -210,6 +218,12 @@ class StoreApi {
    * @return void
    */
    public function deleteOrder($order_id) {
+      
+      // verify the required parameter 'order_id' is set
+      if ($order_id === null) {
+        throw new \Exception("Missing the required parameter $order_id when calling deleteOrder");
+      }
+      
 
       // parse inputs
       $resourcePath = "/store/order/{orderId}";
diff --git a/samples/client/petstore/php/SwaggerClient-php/lib/UserApi.php b/samples/client/petstore/php/SwaggerClient-php/lib/UserApi.php
index f3e9e7f4cc6b..8296d5e92fd7 100644
--- a/samples/client/petstore/php/SwaggerClient-php/lib/UserApi.php
+++ b/samples/client/petstore/php/SwaggerClient-php/lib/UserApi.php
@@ -38,6 +38,7 @@ class UserApi {
    * @return void
    */
    public function createUser($body) {
+      
 
       // parse inputs
       $resourcePath = "/user";
@@ -91,6 +92,7 @@ class UserApi {
    * @return void
    */
    public function createUsersWithArrayInput($body) {
+      
 
       // parse inputs
       $resourcePath = "/user/createWithArray";
@@ -144,6 +146,7 @@ class UserApi {
    * @return void
    */
    public function createUsersWithListInput($body) {
+      
 
       // parse inputs
       $resourcePath = "/user/createWithList";
@@ -198,6 +201,7 @@ class UserApi {
    * @return string
    */
    public function loginUser($username, $password) {
+      
 
       // parse inputs
       $resourcePath = "/user/login";
@@ -258,6 +262,7 @@ class UserApi {
    * @return void
    */
    public function logoutUser() {
+      
 
       // parse inputs
       $resourcePath = "/user/logout";
@@ -307,6 +312,12 @@ class UserApi {
    * @return User
    */
    public function getUserByName($username) {
+      
+      // verify the required parameter 'username' is set
+      if ($username === null) {
+        throw new \Exception("Missing the required parameter $username when calling getUserByName");
+      }
+      
 
       // parse inputs
       $resourcePath = "/user/{username}";
@@ -367,6 +378,12 @@ class UserApi {
    * @return void
    */
    public function updateUser($username, $body) {
+      
+      // verify the required parameter 'username' is set
+      if ($username === null) {
+        throw new \Exception("Missing the required parameter $username when calling updateUser");
+      }
+      
 
       // parse inputs
       $resourcePath = "/user/{username}";
@@ -424,6 +441,12 @@ class UserApi {
    * @return void
    */
    public function deleteUser($username) {
+      
+      // verify the required parameter 'username' is set
+      if ($username === null) {
+        throw new \Exception("Missing the required parameter $username when calling deleteUser");
+      }
+      
 
       // parse inputs
       $resourcePath = "/user/{username}";
diff --git a/samples/client/petstore/ruby/lib/pet_api.rb b/samples/client/petstore/ruby/lib/pet_api.rb
index 6b032510c416..7cab0c8eb008 100644
--- a/samples/client/petstore/ruby/lib/pet_api.rb
+++ b/samples/client/petstore/ruby/lib/pet_api.rb
@@ -10,7 +10,7 @@ class PetApi
   # @option opts [Pet] :body Pet object that needs to be added to the store
   # @return void
   def self.update_pet(opts = {})
-    # verify existence of params
+    
 
     # resource path
     path = "/pet".sub('{format}','json')
@@ -62,7 +62,7 @@ class PetApi
   # @option opts [Pet] :body Pet object that needs to be added to the store
   # @return void
   def self.add_pet(opts = {})
-    # verify existence of params
+    
 
     # resource path
     path = "/pet".sub('{format}','json')
@@ -114,7 +114,7 @@ class PetApi
   # @option opts [array[string]] :status Status values that need to be considered for filter
   # @return array[Pet]
   def self.find_pets_by_status(opts = {})
-    # verify existence of params
+    
 
     # resource path
     path = "/pet/findByStatus".sub('{format}','json')
@@ -148,7 +148,7 @@ class PetApi
   # @option opts [array[string]] :tags Tags to filter by
   # @return array[Pet]
   def self.find_pets_by_tags(opts = {})
-    # verify existence of params
+    
 
     # resource path
     path = "/pet/findByTags".sub('{format}','json')
@@ -182,8 +182,10 @@ class PetApi
   # @param [Hash] opts the optional parameters
   # @return Pet
   def self.get_pet_by_id(pet_id, opts = {})
-    # verify existence of params
-    raise "pet_id is required" if pet_id.nil?
+    
+    # verify the required parameter 'pet_id' is set
+    raise "Missing the required parameter 'pet_id' when calling get_pet_by_id" if pet_id.nil?
+    
 
     # resource path
     path = "/pet/{petId}".sub('{format}','json').sub('{' + 'petId' + '}', pet_id.to_s)
@@ -218,8 +220,10 @@ class PetApi
   # @option opts [string] :status Updated status of the pet
   # @return void
   def self.update_pet_with_form(pet_id, opts = {})
-    # verify existence of params
-    raise "pet_id is required" if pet_id.nil?
+    
+    # verify the required parameter 'pet_id' is set
+    raise "Missing the required parameter 'pet_id' when calling update_pet_with_form" if pet_id.nil?
+    
 
     # resource path
     path = "/pet/{petId}".sub('{format}','json').sub('{' + 'petId' + '}', pet_id.to_s)
@@ -254,8 +258,10 @@ class PetApi
   # @option opts [string] :api_key 
   # @return void
   def self.delete_pet(pet_id, opts = {})
-    # verify existence of params
-    raise "pet_id is required" if pet_id.nil?
+    
+    # verify the required parameter 'pet_id' is set
+    raise "Missing the required parameter 'pet_id' when calling delete_pet" if pet_id.nil?
+    
 
     # resource path
     path = "/pet/{petId}".sub('{format}','json').sub('{' + 'petId' + '}', pet_id.to_s)
@@ -290,8 +296,10 @@ class PetApi
   # @option opts [file] :file file to upload
   # @return void
   def self.upload_file(pet_id, opts = {})
-    # verify existence of params
-    raise "pet_id is required" if pet_id.nil?
+    
+    # verify the required parameter 'pet_id' is set
+    raise "Missing the required parameter 'pet_id' when calling upload_file" if pet_id.nil?
+    
 
     # resource path
     path = "/pet/{petId}/uploadImage".sub('{format}','json').sub('{' + 'petId' + '}', pet_id.to_s)
diff --git a/samples/client/petstore/ruby/lib/store_api.rb b/samples/client/petstore/ruby/lib/store_api.rb
index 6cd3296039bf..1ce553cde9a9 100644
--- a/samples/client/petstore/ruby/lib/store_api.rb
+++ b/samples/client/petstore/ruby/lib/store_api.rb
@@ -9,7 +9,7 @@ class StoreApi
   # @param [Hash] opts the optional parameters
   # @return map[string,int]
   def self.get_inventory(opts = {})
-    # verify existence of params
+    
 
     # resource path
     path = "/store/inventory".sub('{format}','json')
@@ -42,7 +42,7 @@ class StoreApi
   # @option opts [Order] :body order placed for purchasing the pet
   # @return Order
   def self.place_order(opts = {})
-    # verify existence of params
+    
 
     # resource path
     path = "/store/order".sub('{format}','json')
@@ -95,8 +95,10 @@ class StoreApi
   # @param [Hash] opts the optional parameters
   # @return Order
   def self.get_order_by_id(order_id, opts = {})
-    # verify existence of params
-    raise "order_id is required" if order_id.nil?
+    
+    # verify the required parameter 'order_id' is set
+    raise "Missing the required parameter 'order_id' when calling get_order_by_id" if order_id.nil?
+    
 
     # resource path
     path = "/store/order/{orderId}".sub('{format}','json').sub('{' + 'orderId' + '}', order_id.to_s)
@@ -129,8 +131,10 @@ class StoreApi
   # @param [Hash] opts the optional parameters
   # @return void
   def self.delete_order(order_id, opts = {})
-    # verify existence of params
-    raise "order_id is required" if order_id.nil?
+    
+    # verify the required parameter 'order_id' is set
+    raise "Missing the required parameter 'order_id' when calling delete_order" if order_id.nil?
+    
 
     # resource path
     path = "/store/order/{orderId}".sub('{format}','json').sub('{' + 'orderId' + '}', order_id.to_s)
diff --git a/samples/client/petstore/ruby/lib/user_api.rb b/samples/client/petstore/ruby/lib/user_api.rb
index dead94897cd3..fa900d3d0059 100644
--- a/samples/client/petstore/ruby/lib/user_api.rb
+++ b/samples/client/petstore/ruby/lib/user_api.rb
@@ -10,7 +10,7 @@ class UserApi
   # @option opts [User] :body Created user object
   # @return void
   def self.create_user(opts = {})
-    # verify existence of params
+    
 
     # resource path
     path = "/user".sub('{format}','json')
@@ -62,7 +62,7 @@ class UserApi
   # @option opts [array[User]] :body List of user object
   # @return void
   def self.create_users_with_array_input(opts = {})
-    # verify existence of params
+    
 
     # resource path
     path = "/user/createWithArray".sub('{format}','json')
@@ -114,7 +114,7 @@ class UserApi
   # @option opts [array[User]] :body List of user object
   # @return void
   def self.create_users_with_list_input(opts = {})
-    # verify existence of params
+    
 
     # resource path
     path = "/user/createWithList".sub('{format}','json')
@@ -167,7 +167,7 @@ class UserApi
   # @option opts [string] :password The password for login in clear text
   # @return string
   def self.login_user(opts = {})
-    # verify existence of params
+    
 
     # resource path
     path = "/user/login".sub('{format}','json')
@@ -201,7 +201,7 @@ class UserApi
   # @param [Hash] opts the optional parameters
   # @return void
   def self.logout_user(opts = {})
-    # verify existence of params
+    
 
     # resource path
     path = "/user/logout".sub('{format}','json')
@@ -233,8 +233,10 @@ class UserApi
   # @param [Hash] opts the optional parameters
   # @return User
   def self.get_user_by_name(username, opts = {})
-    # verify existence of params
-    raise "username is required" if username.nil?
+    
+    # verify the required parameter 'username' is set
+    raise "Missing the required parameter 'username' when calling get_user_by_name" if username.nil?
+    
 
     # resource path
     path = "/user/{username}".sub('{format}','json').sub('{' + 'username' + '}', username.to_s)
@@ -268,8 +270,10 @@ class UserApi
   # @option opts [User] :body Updated user object
   # @return void
   def self.update_user(username, opts = {})
-    # verify existence of params
-    raise "username is required" if username.nil?
+    
+    # verify the required parameter 'username' is set
+    raise "Missing the required parameter 'username' when calling update_user" if username.nil?
+    
 
     # resource path
     path = "/user/{username}".sub('{format}','json').sub('{' + 'username' + '}', username.to_s)
@@ -321,8 +325,10 @@ class UserApi
   # @param [Hash] opts the optional parameters
   # @return void
   def self.delete_user(username, opts = {})
-    # verify existence of params
-    raise "username is required" if username.nil?
+    
+    # verify the required parameter 'username' is set
+    raise "Missing the required parameter 'username' when calling delete_user" if username.nil?
+    
 
     # resource path
     path = "/user/{username}".sub('{format}','json').sub('{' + 'username' + '}', username.to_s)