diff --git a/modules/openapi-generator/src/test/resources/2_0/c/petstore.yaml b/modules/openapi-generator/src/test/resources/2_0/c/petstore.yaml
index c5125f976e7..082c039eadb 100644
--- a/modules/openapi-generator/src/test/resources/2_0/c/petstore.yaml
+++ b/modules/openapi-generator/src/test/resources/2_0/c/petstore.yaml
@@ -75,6 +75,24 @@ paths:
         - petstore_auth:
             - 'write:pets'
             - 'read:pets'
+  /pet/specialty:
+    get:
+      tags:
+        - pet
+      summary: Specialty of the shop
+      description: Returns the kind of pet the store specializes in
+      operationId: specialtyPet
+      produces:
+        - application/xml
+        - application/json
+      parameters: []
+      responses:
+        '200':
+          description: successful operation
+          schema:
+            $ref: '#/definitions/Preference'
+      security:
+        - api_key: []
   /pet/findByStatus:
     get:
       tags:
@@ -626,6 +644,17 @@ definitions:
         type: string
     xml:
       name: Category
+  Preference:
+    title: Pet preference
+    description: A user's preference in pets
+    type: string
+    enum:
+      - cats
+      - dogs
+      - birds
+      - fish
+      - snakes
+      - other
   User:
     title: a User
     description: A User who is purchasing from the pet store
@@ -650,6 +679,12 @@ definitions:
         type: integer
         format: int32
         description: User Status
+      extra:
+        type: object
+        nullable: true
+        additionalProperties: true
+      preference:
+        $ref: '#/definitions/Preference'
     xml:
       name: User
   Tag:
diff --git a/samples/client/petstore/c-useJsonUnformatted/.openapi-generator/FILES b/samples/client/petstore/c-useJsonUnformatted/.openapi-generator/FILES
index 56afd08ac99..043461c7a2e 100644
--- a/samples/client/petstore/c-useJsonUnformatted/.openapi-generator/FILES
+++ b/samples/client/petstore/c-useJsonUnformatted/.openapi-generator/FILES
@@ -16,6 +16,7 @@ docs/category.md
 docs/model_with_set_propertes.md
 docs/order.md
 docs/pet.md
+docs/preference.md
 docs/tag.md
 docs/user.md
 external/cJSON.c
@@ -41,6 +42,8 @@ model/order.c
 model/order.h
 model/pet.c
 model/pet.h
+model/preference.c
+model/preference.h
 model/tag.c
 model/tag.h
 model/user.c
diff --git a/samples/client/petstore/c-useJsonUnformatted/CMakeLists.txt b/samples/client/petstore/c-useJsonUnformatted/CMakeLists.txt
index e41b31d33ab..7eab107fda2 100644
--- a/samples/client/petstore/c-useJsonUnformatted/CMakeLists.txt
+++ b/samples/client/petstore/c-useJsonUnformatted/CMakeLists.txt
@@ -60,6 +60,7 @@ set(SRCS
     model/model_with_set_propertes.c
     model/order.c
     model/pet.c
+    model/preference.c
     model/tag.c
     model/user.c
     api/PetAPI.c
@@ -82,6 +83,7 @@ set(HDRS
     model/model_with_set_propertes.h
     model/order.h
     model/pet.h
+    model/preference.h
     model/tag.h
     model/user.h
     api/PetAPI.h
diff --git a/samples/client/petstore/c-useJsonUnformatted/README.md b/samples/client/petstore/c-useJsonUnformatted/README.md
index a2724768f15..707999204fb 100644
--- a/samples/client/petstore/c-useJsonUnformatted/README.md
+++ b/samples/client/petstore/c-useJsonUnformatted/README.md
@@ -70,6 +70,7 @@ Category | Method | HTTP request | Description
 *PetAPI* | [**PetAPI_findPetsByStatus**](docs/PetAPI.md#PetAPI_findPetsByStatus) | **GET** /pet/findByStatus | Finds Pets by status
 *PetAPI* | [**PetAPI_findPetsByTags**](docs/PetAPI.md#PetAPI_findPetsByTags) | **GET** /pet/findByTags | Finds Pets by tags
 *PetAPI* | [**PetAPI_getPetById**](docs/PetAPI.md#PetAPI_getPetById) | **GET** /pet/{petId} | Find pet by ID
+*PetAPI* | [**PetAPI_specialtyPet**](docs/PetAPI.md#PetAPI_specialtyPet) | **GET** /pet/specialty | Specialty of the shop
 *PetAPI* | [**PetAPI_updatePet**](docs/PetAPI.md#PetAPI_updatePet) | **PUT** /pet | Update an existing pet
 *PetAPI* | [**PetAPI_updatePetWithForm**](docs/PetAPI.md#PetAPI_updatePetWithForm) | **POST** /pet/{petId} | Updates a pet in the store with form data
 *PetAPI* | [**PetAPI_uploadFile**](docs/PetAPI.md#PetAPI_uploadFile) | **POST** /pet/{petId}/uploadImage | uploads an image
@@ -96,6 +97,7 @@ Category | Method | HTTP request | Description
  - [model_with_set_propertes_t](docs/model_with_set_propertes.md)
  - [order_t](docs/order.md)
  - [pet_t](docs/pet.md)
+ - [preference_t](docs/preference.md)
  - [tag_t](docs/tag.md)
  - [user_t](docs/user.md)
 
diff --git a/samples/client/petstore/c-useJsonUnformatted/api/PetAPI.c b/samples/client/petstore/c-useJsonUnformatted/api/PetAPI.c
index f17d4fd0c26..6cb279c58bb 100644
--- a/samples/client/petstore/c-useJsonUnformatted/api/PetAPI.c
+++ b/samples/client/petstore/c-useJsonUnformatted/api/PetAPI.c
@@ -460,6 +460,70 @@ end:
 
 }
 
+// Specialty of the shop
+//
+// Returns the kind of pet the store specializes in
+//
+openapi_petstore_preference__e
+PetAPI_specialtyPet(apiClient_t *apiClient)
+{
+    list_t    *localVarQueryParameters = NULL;
+    list_t    *localVarHeaderParameters = NULL;
+    list_t    *localVarFormParameters = NULL;
+    list_t *localVarHeaderType = list_createList();
+    list_t *localVarContentType = NULL;
+    char      *localVarBodyParameters = NULL;
+
+    // create the path
+    long sizeOfPath = strlen("/pet/specialty")+1;
+    char *localVarPath = malloc(sizeOfPath);
+    snprintf(localVarPath, sizeOfPath, "/pet/specialty");
+
+
+
+    list_addElement(localVarHeaderType,"application/xml"); //produces
+    list_addElement(localVarHeaderType,"application/json"); //produces
+    apiClient_invoke(apiClient,
+                    localVarPath,
+                    localVarQueryParameters,
+                    localVarHeaderParameters,
+                    localVarFormParameters,
+                    localVarHeaderType,
+                    localVarContentType,
+                    localVarBodyParameters,
+                    "GET");
+
+    // uncomment below to debug the error response
+    //if (apiClient->response_code == 200) {
+    //    printf("%s\n","successful operation");
+    //}
+    //nonprimitive not container
+    cJSON *PetAPIlocalVarJSON = cJSON_Parse(apiClient->dataReceived);
+    openapi_petstore_preference__e elementToReturn = preference_parseFromJSON(PetAPIlocalVarJSON);
+    cJSON_Delete(PetAPIlocalVarJSON);
+    if(elementToReturn == 0) {
+        // return 0;
+    }
+
+    //return type
+    if (apiClient->dataReceived) {
+        free(apiClient->dataReceived);
+        apiClient->dataReceived = NULL;
+        apiClient->dataReceivedLen = 0;
+    }
+    
+    
+    
+    list_freeList(localVarHeaderType);
+    
+    free(localVarPath);
+    return elementToReturn;
+end:
+    free(localVarPath);
+    return 0;
+
+}
+
 // Update an existing pet
 //
 void
diff --git a/samples/client/petstore/c-useJsonUnformatted/api/PetAPI.h b/samples/client/petstore/c-useJsonUnformatted/api/PetAPI.h
index 9b5c586fda7..d33d0394b2d 100644
--- a/samples/client/petstore/c-useJsonUnformatted/api/PetAPI.h
+++ b/samples/client/petstore/c-useJsonUnformatted/api/PetAPI.h
@@ -7,6 +7,7 @@
 #include "../include/binary.h"
 #include "../model/api_response.h"
 #include "../model/pet.h"
+#include "../model/preference.h"
 
 // Enum STATUS for PetAPI_findPetsByStatus
 typedef enum  { openapi_petstore_findPetsByStatus_STATUS_NULL = 0, openapi_petstore_findPetsByStatus_STATUS_available, openapi_petstore_findPetsByStatus_STATUS_pending, openapi_petstore_findPetsByStatus_STATUS_sold } openapi_petstore_findPetsByStatus_status_e;
@@ -48,6 +49,14 @@ pet_t*
 PetAPI_getPetById(apiClient_t *apiClient, long petId);
 
 
+// Specialty of the shop
+//
+// Returns the kind of pet the store specializes in
+//
+openapi_petstore_preference__e
+PetAPI_specialtyPet(apiClient_t *apiClient);
+
+
 // Update an existing pet
 //
 void
diff --git a/samples/client/petstore/c-useJsonUnformatted/docs/PetAPI.md b/samples/client/petstore/c-useJsonUnformatted/docs/PetAPI.md
index 392ef4d08a7..bcdc9e8e1c3 100644
--- a/samples/client/petstore/c-useJsonUnformatted/docs/PetAPI.md
+++ b/samples/client/petstore/c-useJsonUnformatted/docs/PetAPI.md
@@ -9,6 +9,7 @@ Method | HTTP request | Description
 [**PetAPI_findPetsByStatus**](PetAPI.md#PetAPI_findPetsByStatus) | **GET** /pet/findByStatus | Finds Pets by status
 [**PetAPI_findPetsByTags**](PetAPI.md#PetAPI_findPetsByTags) | **GET** /pet/findByTags | Finds Pets by tags
 [**PetAPI_getPetById**](PetAPI.md#PetAPI_getPetById) | **GET** /pet/{petId} | Find pet by ID
+[**PetAPI_specialtyPet**](PetAPI.md#PetAPI_specialtyPet) | **GET** /pet/specialty | Specialty of the shop
 [**PetAPI_updatePet**](PetAPI.md#PetAPI_updatePet) | **PUT** /pet | Update an existing pet
 [**PetAPI_updatePetWithForm**](PetAPI.md#PetAPI_updatePetWithForm) | **POST** /pet/{petId} | Updates a pet in the store with form data
 [**PetAPI_uploadFile**](PetAPI.md#PetAPI_uploadFile) | **POST** /pet/{petId}/uploadImage | uploads an image
@@ -153,6 +154,36 @@ Name | Type | Description  | Notes
 [pet_t](pet.md) *
 
 
+### Authorization
+
+[api_key](../README.md#api_key)
+
+### HTTP request headers
+
+ - **Content-Type**: Not defined
+ - **Accept**: application/xml, application/json
+
+[[Back to top]](#) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to Model list]](../README.md#documentation-for-models) [[Back to README]](../README.md)
+
+# **PetAPI_specialtyPet**
+```c
+// Specialty of the shop
+//
+// Returns the kind of pet the store specializes in
+//
+preference_t* PetAPI_specialtyPet(apiClient_t *apiClient);
+```
+
+### Parameters
+Name | Type | Description  | Notes
+------------- | ------------- | ------------- | -------------
+**apiClient** | **apiClient_t \*** | context containing the client configuration |
+
+### Return type
+
+[preference_t](preference.md) *
+
+
 ### Authorization
 
 [api_key](../README.md#api_key)
diff --git a/samples/client/petstore/c-useJsonUnformatted/docs/preference.md b/samples/client/petstore/c-useJsonUnformatted/docs/preference.md
new file mode 100644
index 00000000000..ab63d47cb7e
--- /dev/null
+++ b/samples/client/petstore/c-useJsonUnformatted/docs/preference.md
@@ -0,0 +1,9 @@
+# preference_t
+
+## Properties
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+
diff --git a/samples/client/petstore/c-useJsonUnformatted/docs/user.md b/samples/client/petstore/c-useJsonUnformatted/docs/user.md
index 3b9219c158b..22b807f47ef 100644
--- a/samples/client/petstore/c-useJsonUnformatted/docs/user.md
+++ b/samples/client/petstore/c-useJsonUnformatted/docs/user.md
@@ -11,6 +11,8 @@ Name | Type | Description | Notes
 **password** | **char \*** |  | [optional] 
 **phone** | **char \*** |  | [optional] 
 **user_status** | **int** | User Status | [optional] 
+**extra** | **list_t*** |  | [optional] 
+**preference** | **preference_t \*** |  | [optional] 
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 
diff --git a/samples/client/petstore/c-useJsonUnformatted/model/preference.c b/samples/client/petstore/c-useJsonUnformatted/model/preference.c
new file mode 100644
index 00000000000..ac7e600fed0
--- /dev/null
+++ b/samples/client/petstore/c-useJsonUnformatted/model/preference.c
@@ -0,0 +1,47 @@
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include "preference.h"
+
+
+char* preference_preference_ToString(openapi_petstore_preference__e preference) {
+    char *preferenceArray[] =  { "NULL", "cats", "dogs", "birds", "fish", "snakes", "other" };
+    return preferenceArray[preference];
+}
+
+openapi_petstore_preference__e preference_preference_FromString(char* preference) {
+    int stringToReturn = 0;
+    char *preferenceArray[] =  { "NULL", "cats", "dogs", "birds", "fish", "snakes", "other" };
+    size_t sizeofArray = sizeof(preferenceArray) / sizeof(preferenceArray[0]);
+    while(stringToReturn < sizeofArray) {
+        if(strcmp(preference, preferenceArray[stringToReturn]) == 0) {
+            return stringToReturn;
+        }
+        stringToReturn++;
+    }
+    return 0;
+}
+
+cJSON *preference_convertToJSON(openapi_petstore_preference__e preference) {
+    cJSON *item = cJSON_CreateObject();
+    if(cJSON_AddStringToObject(item, "preference", preference_preference_ToString(preference)) == NULL) {
+        goto fail;
+    }
+    return item;
+fail:
+    cJSON_Delete(item);
+    return NULL;
+}
+
+openapi_petstore_preference__e preference_parseFromJSON(cJSON *preferenceJSON) {
+    openapi_petstore_preference__e *preference = NULL;
+    openapi_petstore_preference__e preferenceVariable;
+    cJSON *preferenceVar = cJSON_GetObjectItemCaseSensitive(preferenceJSON, "preference");
+    if(!cJSON_IsString(preferenceVar) || (preferenceVar->valuestring == NULL)){
+        goto end;
+    }
+    preferenceVariable = preference_preference_FromString(preferenceVar->valuestring);
+    return preferenceVariable;
+end:
+    return 0;
+}
diff --git a/samples/client/petstore/c-useJsonUnformatted/model/preference.h b/samples/client/petstore/c-useJsonUnformatted/model/preference.h
new file mode 100644
index 00000000000..1f6644f0836
--- /dev/null
+++ b/samples/client/petstore/c-useJsonUnformatted/model/preference.h
@@ -0,0 +1,32 @@
+/*
+ * preference.h
+ *
+ * A user&#39;s preference in pets
+ */
+
+#ifndef _preference_H_
+#define _preference_H_
+
+#include <string.h>
+#include "../external/cJSON.h"
+#include "../include/list.h"
+#include "../include/keyValuePair.h"
+#include "../include/binary.h"
+
+typedef struct preference_t preference_t;
+
+
+// Enum  for preference
+
+typedef enum { openapi_petstore_preference__NULL = 0, openapi_petstore_preference__cats, openapi_petstore_preference__dogs, openapi_petstore_preference__birds, openapi_petstore_preference__fish, openapi_petstore_preference__snakes, openapi_petstore_preference__other } openapi_petstore_preference__e;
+
+char* preference_preference_ToString(openapi_petstore_preference__e preference);
+
+openapi_petstore_preference__e preference_preference_FromString(char* preference);
+
+cJSON *preference_convertToJSON(openapi_petstore_preference__e preference);
+
+openapi_petstore_preference__e preference_parseFromJSON(cJSON *preferenceJSON);
+
+#endif /* _preference_H_ */
+
diff --git a/samples/client/petstore/c-useJsonUnformatted/model/user.c b/samples/client/petstore/c-useJsonUnformatted/model/user.c
index eb188153ccf..b43d428e1ff 100644
--- a/samples/client/petstore/c-useJsonUnformatted/model/user.c
+++ b/samples/client/petstore/c-useJsonUnformatted/model/user.c
@@ -13,7 +13,9 @@ user_t *user_create(
     char *email,
     char *password,
     char *phone,
-    int user_status
+    int user_status,
+    list_t* extra,
+    openapi_petstore_preference__e preference
     ) {
     user_t *user_local_var = malloc(sizeof(user_t));
     if (!user_local_var) {
@@ -27,6 +29,8 @@ user_t *user_create(
     user_local_var->password = password;
     user_local_var->phone = phone;
     user_local_var->user_status = user_status;
+    user_local_var->extra = extra;
+    user_local_var->preference = preference;
 
     return user_local_var;
 }
@@ -61,6 +65,16 @@ void user_free(user_t *user) {
         free(user->phone);
         user->phone = NULL;
     }
+    if (user->extra) {
+        list_ForEach(listEntry, user->extra) {
+            keyValuePair_t *localKeyValue = (keyValuePair_t*) listEntry->data;
+            free (localKeyValue->key);
+            free (localKeyValue->value);
+            keyValuePair_free(localKeyValue);
+        }
+        list_freeList(user->extra);
+        user->extra = NULL;
+    }
     free(user);
 }
 
@@ -130,6 +144,35 @@ cJSON *user_convertToJSON(user_t *user) {
     }
     }
 
+
+    // user->extra
+    if(user->extra) {
+    cJSON *extra = cJSON_AddObjectToObject(item, "extra");
+    if(extra == NULL) {
+        goto fail; //primitive map container
+    }
+    cJSON *localMapObject = extra;
+    listEntry_t *extraListEntry;
+    if (user->extra) {
+    list_ForEach(extraListEntry, user->extra) {
+        keyValuePair_t *localKeyValue = (keyValuePair_t*)extraListEntry->data;
+    }
+    }
+    }
+
+
+    // user->preference
+    if(user->preference != openapi_petstore_preference__NULL) {
+    cJSON *preference_local_JSON = preference_convertToJSON(user->preference);
+    if(preference_local_JSON == NULL) {
+        goto fail; // custom
+    }
+    cJSON_AddItemToObject(item, "preference", preference_local_JSON);
+    if(item->child == NULL) {
+        goto fail;
+    }
+    }
+
     return item;
 fail:
     if (item) {
@@ -142,6 +185,12 @@ user_t *user_parseFromJSON(cJSON *userJSON){
 
     user_t *user_local_var = NULL;
 
+    // define the local map for user->extra
+    list_t *extraList = NULL;
+
+    // define the local variable for user->preference
+    openapi_petstore_preference__e preference_local_nonprim = 0;
+
     // user->id
     cJSON *id = cJSON_GetObjectItemCaseSensitive(userJSON, "id");
     if (id) { 
@@ -214,6 +263,32 @@ user_t *user_parseFromJSON(cJSON *userJSON){
     }
     }
 
+    // user->extra
+    cJSON *extra = cJSON_GetObjectItemCaseSensitive(userJSON, "extra");
+    if (extra) { 
+    cJSON *extra_local_map = NULL;
+    if(!cJSON_IsObject(extra) && !cJSON_IsNull(extra))
+    {
+        goto end;//primitive map container
+    }
+    if(cJSON_IsObject(extra))
+    {
+        extraList = list_createList();
+        keyValuePair_t *localMapKeyPair;
+        cJSON_ArrayForEach(extra_local_map, extra)
+        {
+            cJSON *localMapObject = extra_local_map;
+            list_addElement(extraList , localMapKeyPair);
+        }
+    }
+    }
+
+    // user->preference
+    cJSON *preference = cJSON_GetObjectItemCaseSensitive(userJSON, "preference");
+    if (preference) { 
+    preference_local_nonprim = preference_parseFromJSON(preference); //custom
+    }
+
 
     user_local_var = user_create (
         id ? id->valuedouble : 0,
@@ -223,11 +298,28 @@ user_t *user_parseFromJSON(cJSON *userJSON){
         email && !cJSON_IsNull(email) ? strdup(email->valuestring) : NULL,
         password && !cJSON_IsNull(password) ? strdup(password->valuestring) : NULL,
         phone && !cJSON_IsNull(phone) ? strdup(phone->valuestring) : NULL,
-        user_status ? user_status->valuedouble : 0
+        user_status ? user_status->valuedouble : 0,
+        extra ? extraList : NULL,
+        preference ? preference_local_nonprim : 0
         );
 
     return user_local_var;
 end:
+    if (extraList) {
+        listEntry_t *listEntry = NULL;
+        list_ForEach(listEntry, extraList) {
+            keyValuePair_t *localKeyValue = (keyValuePair_t*) listEntry->data;
+            free(localKeyValue->key);
+            localKeyValue->key = NULL;
+            keyValuePair_free(localKeyValue);
+            localKeyValue = NULL;
+        }
+        list_freeList(extraList);
+        extraList = NULL;
+    }
+    if (preference_local_nonprim) {
+        preference_local_nonprim = 0;
+    }
     return NULL;
 
 }
diff --git a/samples/client/petstore/c-useJsonUnformatted/model/user.h b/samples/client/petstore/c-useJsonUnformatted/model/user.h
index 45fa42c3f91..badbc747b30 100644
--- a/samples/client/petstore/c-useJsonUnformatted/model/user.h
+++ b/samples/client/petstore/c-useJsonUnformatted/model/user.h
@@ -15,6 +15,8 @@
 
 typedef struct user_t user_t;
 
+#include "any_type.h"
+#include "preference.h"
 
 
 
@@ -27,6 +29,8 @@ typedef struct user_t {
     char *password; // string
     char *phone; // string
     int user_status; //numeric
+    list_t* extra; //map
+    openapi_petstore_preference__e preference; //referenced enum
 
 } user_t;
 
@@ -38,7 +42,9 @@ user_t *user_create(
     char *email,
     char *password,
     char *phone,
-    int user_status
+    int user_status,
+    list_t* extra,
+    openapi_petstore_preference__e preference
 );
 
 void user_free(user_t *user);
diff --git a/samples/client/petstore/c-useJsonUnformatted/unit-test/test_preference.c b/samples/client/petstore/c-useJsonUnformatted/unit-test/test_preference.c
new file mode 100644
index 00000000000..96468361f58
--- /dev/null
+++ b/samples/client/petstore/c-useJsonUnformatted/unit-test/test_preference.c
@@ -0,0 +1,56 @@
+#ifndef preference_TEST
+#define preference_TEST
+
+// the following is to include only the main from the first c file
+#ifndef TEST_MAIN
+#define TEST_MAIN
+#define preference_MAIN
+#endif // TEST_MAIN
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include "../external/cJSON.h"
+
+#include "../model/preference.h"
+preference_t* instantiate_preference(int include_optional);
+
+
+
+preference_t* instantiate_preference(int include_optional) {
+  preference_t* preference = NULL;
+  if (include_optional) {
+    preference = preference_create(
+    );
+  } else {
+    preference = preference_create(
+    );
+  }
+
+  return preference;
+}
+
+
+#ifdef preference_MAIN
+
+void test_preference(int include_optional) {
+    preference_t* preference_1 = instantiate_preference(include_optional);
+
+	cJSON* jsonpreference_1 = preference_convertToJSON(preference_1);
+	printf("preference :\n%s\n", cJSON_PrintUnformatted(jsonpreference_1));
+	preference_t* preference_2 = preference_parseFromJSON(jsonpreference_1);
+	cJSON* jsonpreference_2 = preference_convertToJSON(preference_2);
+	printf("repeating preference:\n%s\n", cJSON_PrintUnformatted(jsonpreference_2));
+}
+
+int main() {
+  test_preference(1);
+  test_preference(0);
+
+  printf("Hello world \n");
+  return 0;
+}
+
+#endif // preference_MAIN
+#endif // preference_TEST
diff --git a/samples/client/petstore/c/.openapi-generator/FILES b/samples/client/petstore/c/.openapi-generator/FILES
index 4f6e6397e71..eff7ae71434 100644
--- a/samples/client/petstore/c/.openapi-generator/FILES
+++ b/samples/client/petstore/c/.openapi-generator/FILES
@@ -15,6 +15,7 @@ docs/category.md
 docs/model_with_set_propertes.md
 docs/order.md
 docs/pet.md
+docs/preference.md
 docs/tag.md
 docs/user.md
 external/cJSON.c
@@ -40,6 +41,8 @@ model/order.c
 model/order.h
 model/pet.c
 model/pet.h
+model/preference.c
+model/preference.h
 model/tag.c
 model/tag.h
 model/user.c
diff --git a/samples/client/petstore/c/README.md b/samples/client/petstore/c/README.md
index a2724768f15..707999204fb 100644
--- a/samples/client/petstore/c/README.md
+++ b/samples/client/petstore/c/README.md
@@ -70,6 +70,7 @@ Category | Method | HTTP request | Description
 *PetAPI* | [**PetAPI_findPetsByStatus**](docs/PetAPI.md#PetAPI_findPetsByStatus) | **GET** /pet/findByStatus | Finds Pets by status
 *PetAPI* | [**PetAPI_findPetsByTags**](docs/PetAPI.md#PetAPI_findPetsByTags) | **GET** /pet/findByTags | Finds Pets by tags
 *PetAPI* | [**PetAPI_getPetById**](docs/PetAPI.md#PetAPI_getPetById) | **GET** /pet/{petId} | Find pet by ID
+*PetAPI* | [**PetAPI_specialtyPet**](docs/PetAPI.md#PetAPI_specialtyPet) | **GET** /pet/specialty | Specialty of the shop
 *PetAPI* | [**PetAPI_updatePet**](docs/PetAPI.md#PetAPI_updatePet) | **PUT** /pet | Update an existing pet
 *PetAPI* | [**PetAPI_updatePetWithForm**](docs/PetAPI.md#PetAPI_updatePetWithForm) | **POST** /pet/{petId} | Updates a pet in the store with form data
 *PetAPI* | [**PetAPI_uploadFile**](docs/PetAPI.md#PetAPI_uploadFile) | **POST** /pet/{petId}/uploadImage | uploads an image
@@ -96,6 +97,7 @@ Category | Method | HTTP request | Description
  - [model_with_set_propertes_t](docs/model_with_set_propertes.md)
  - [order_t](docs/order.md)
  - [pet_t](docs/pet.md)
+ - [preference_t](docs/preference.md)
  - [tag_t](docs/tag.md)
  - [user_t](docs/user.md)
 
diff --git a/samples/client/petstore/c/api/PetAPI.c b/samples/client/petstore/c/api/PetAPI.c
index 36303a0ef5e..9cf09a2e4ad 100644
--- a/samples/client/petstore/c/api/PetAPI.c
+++ b/samples/client/petstore/c/api/PetAPI.c
@@ -460,6 +460,70 @@ end:
 
 }
 
+// Specialty of the shop
+//
+// Returns the kind of pet the store specializes in
+//
+openapi_petstore_preference__e
+PetAPI_specialtyPet(apiClient_t *apiClient)
+{
+    list_t    *localVarQueryParameters = NULL;
+    list_t    *localVarHeaderParameters = NULL;
+    list_t    *localVarFormParameters = NULL;
+    list_t *localVarHeaderType = list_createList();
+    list_t *localVarContentType = NULL;
+    char      *localVarBodyParameters = NULL;
+
+    // create the path
+    long sizeOfPath = strlen("/pet/specialty")+1;
+    char *localVarPath = malloc(sizeOfPath);
+    snprintf(localVarPath, sizeOfPath, "/pet/specialty");
+
+
+
+    list_addElement(localVarHeaderType,"application/xml"); //produces
+    list_addElement(localVarHeaderType,"application/json"); //produces
+    apiClient_invoke(apiClient,
+                    localVarPath,
+                    localVarQueryParameters,
+                    localVarHeaderParameters,
+                    localVarFormParameters,
+                    localVarHeaderType,
+                    localVarContentType,
+                    localVarBodyParameters,
+                    "GET");
+
+    // uncomment below to debug the error response
+    //if (apiClient->response_code == 200) {
+    //    printf("%s\n","successful operation");
+    //}
+    //nonprimitive not container
+    cJSON *PetAPIlocalVarJSON = cJSON_Parse(apiClient->dataReceived);
+    openapi_petstore_preference__e elementToReturn = preference_parseFromJSON(PetAPIlocalVarJSON);
+    cJSON_Delete(PetAPIlocalVarJSON);
+    if(elementToReturn == 0) {
+        // return 0;
+    }
+
+    //return type
+    if (apiClient->dataReceived) {
+        free(apiClient->dataReceived);
+        apiClient->dataReceived = NULL;
+        apiClient->dataReceivedLen = 0;
+    }
+    
+    
+    
+    list_freeList(localVarHeaderType);
+    
+    free(localVarPath);
+    return elementToReturn;
+end:
+    free(localVarPath);
+    return 0;
+
+}
+
 // Update an existing pet
 //
 void
diff --git a/samples/client/petstore/c/api/PetAPI.h b/samples/client/petstore/c/api/PetAPI.h
index 9b5c586fda7..d33d0394b2d 100644
--- a/samples/client/petstore/c/api/PetAPI.h
+++ b/samples/client/petstore/c/api/PetAPI.h
@@ -7,6 +7,7 @@
 #include "../include/binary.h"
 #include "../model/api_response.h"
 #include "../model/pet.h"
+#include "../model/preference.h"
 
 // Enum STATUS for PetAPI_findPetsByStatus
 typedef enum  { openapi_petstore_findPetsByStatus_STATUS_NULL = 0, openapi_petstore_findPetsByStatus_STATUS_available, openapi_petstore_findPetsByStatus_STATUS_pending, openapi_petstore_findPetsByStatus_STATUS_sold } openapi_petstore_findPetsByStatus_status_e;
@@ -48,6 +49,14 @@ pet_t*
 PetAPI_getPetById(apiClient_t *apiClient, long petId);
 
 
+// Specialty of the shop
+//
+// Returns the kind of pet the store specializes in
+//
+openapi_petstore_preference__e
+PetAPI_specialtyPet(apiClient_t *apiClient);
+
+
 // Update an existing pet
 //
 void
diff --git a/samples/client/petstore/c/docs/PetAPI.md b/samples/client/petstore/c/docs/PetAPI.md
index 392ef4d08a7..bcdc9e8e1c3 100644
--- a/samples/client/petstore/c/docs/PetAPI.md
+++ b/samples/client/petstore/c/docs/PetAPI.md
@@ -9,6 +9,7 @@ Method | HTTP request | Description
 [**PetAPI_findPetsByStatus**](PetAPI.md#PetAPI_findPetsByStatus) | **GET** /pet/findByStatus | Finds Pets by status
 [**PetAPI_findPetsByTags**](PetAPI.md#PetAPI_findPetsByTags) | **GET** /pet/findByTags | Finds Pets by tags
 [**PetAPI_getPetById**](PetAPI.md#PetAPI_getPetById) | **GET** /pet/{petId} | Find pet by ID
+[**PetAPI_specialtyPet**](PetAPI.md#PetAPI_specialtyPet) | **GET** /pet/specialty | Specialty of the shop
 [**PetAPI_updatePet**](PetAPI.md#PetAPI_updatePet) | **PUT** /pet | Update an existing pet
 [**PetAPI_updatePetWithForm**](PetAPI.md#PetAPI_updatePetWithForm) | **POST** /pet/{petId} | Updates a pet in the store with form data
 [**PetAPI_uploadFile**](PetAPI.md#PetAPI_uploadFile) | **POST** /pet/{petId}/uploadImage | uploads an image
@@ -153,6 +154,36 @@ Name | Type | Description  | Notes
 [pet_t](pet.md) *
 
 
+### Authorization
+
+[api_key](../README.md#api_key)
+
+### HTTP request headers
+
+ - **Content-Type**: Not defined
+ - **Accept**: application/xml, application/json
+
+[[Back to top]](#) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to Model list]](../README.md#documentation-for-models) [[Back to README]](../README.md)
+
+# **PetAPI_specialtyPet**
+```c
+// Specialty of the shop
+//
+// Returns the kind of pet the store specializes in
+//
+preference_t* PetAPI_specialtyPet(apiClient_t *apiClient);
+```
+
+### Parameters
+Name | Type | Description  | Notes
+------------- | ------------- | ------------- | -------------
+**apiClient** | **apiClient_t \*** | context containing the client configuration |
+
+### Return type
+
+[preference_t](preference.md) *
+
+
 ### Authorization
 
 [api_key](../README.md#api_key)
diff --git a/samples/client/petstore/c/docs/preference.md b/samples/client/petstore/c/docs/preference.md
new file mode 100644
index 00000000000..ab63d47cb7e
--- /dev/null
+++ b/samples/client/petstore/c/docs/preference.md
@@ -0,0 +1,9 @@
+# preference_t
+
+## Properties
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+
diff --git a/samples/client/petstore/c/docs/user.md b/samples/client/petstore/c/docs/user.md
index 3b9219c158b..22b807f47ef 100644
--- a/samples/client/petstore/c/docs/user.md
+++ b/samples/client/petstore/c/docs/user.md
@@ -11,6 +11,8 @@ Name | Type | Description | Notes
 **password** | **char \*** |  | [optional] 
 **phone** | **char \*** |  | [optional] 
 **user_status** | **int** | User Status | [optional] 
+**extra** | **list_t*** |  | [optional] 
+**preference** | **preference_t \*** |  | [optional] 
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 
diff --git a/samples/client/petstore/c/model/preference.c b/samples/client/petstore/c/model/preference.c
new file mode 100644
index 00000000000..ac7e600fed0
--- /dev/null
+++ b/samples/client/petstore/c/model/preference.c
@@ -0,0 +1,47 @@
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include "preference.h"
+
+
+char* preference_preference_ToString(openapi_petstore_preference__e preference) {
+    char *preferenceArray[] =  { "NULL", "cats", "dogs", "birds", "fish", "snakes", "other" };
+    return preferenceArray[preference];
+}
+
+openapi_petstore_preference__e preference_preference_FromString(char* preference) {
+    int stringToReturn = 0;
+    char *preferenceArray[] =  { "NULL", "cats", "dogs", "birds", "fish", "snakes", "other" };
+    size_t sizeofArray = sizeof(preferenceArray) / sizeof(preferenceArray[0]);
+    while(stringToReturn < sizeofArray) {
+        if(strcmp(preference, preferenceArray[stringToReturn]) == 0) {
+            return stringToReturn;
+        }
+        stringToReturn++;
+    }
+    return 0;
+}
+
+cJSON *preference_convertToJSON(openapi_petstore_preference__e preference) {
+    cJSON *item = cJSON_CreateObject();
+    if(cJSON_AddStringToObject(item, "preference", preference_preference_ToString(preference)) == NULL) {
+        goto fail;
+    }
+    return item;
+fail:
+    cJSON_Delete(item);
+    return NULL;
+}
+
+openapi_petstore_preference__e preference_parseFromJSON(cJSON *preferenceJSON) {
+    openapi_petstore_preference__e *preference = NULL;
+    openapi_petstore_preference__e preferenceVariable;
+    cJSON *preferenceVar = cJSON_GetObjectItemCaseSensitive(preferenceJSON, "preference");
+    if(!cJSON_IsString(preferenceVar) || (preferenceVar->valuestring == NULL)){
+        goto end;
+    }
+    preferenceVariable = preference_preference_FromString(preferenceVar->valuestring);
+    return preferenceVariable;
+end:
+    return 0;
+}
diff --git a/samples/client/petstore/c/model/preference.h b/samples/client/petstore/c/model/preference.h
new file mode 100644
index 00000000000..1f6644f0836
--- /dev/null
+++ b/samples/client/petstore/c/model/preference.h
@@ -0,0 +1,32 @@
+/*
+ * preference.h
+ *
+ * A user&#39;s preference in pets
+ */
+
+#ifndef _preference_H_
+#define _preference_H_
+
+#include <string.h>
+#include "../external/cJSON.h"
+#include "../include/list.h"
+#include "../include/keyValuePair.h"
+#include "../include/binary.h"
+
+typedef struct preference_t preference_t;
+
+
+// Enum  for preference
+
+typedef enum { openapi_petstore_preference__NULL = 0, openapi_petstore_preference__cats, openapi_petstore_preference__dogs, openapi_petstore_preference__birds, openapi_petstore_preference__fish, openapi_petstore_preference__snakes, openapi_petstore_preference__other } openapi_petstore_preference__e;
+
+char* preference_preference_ToString(openapi_petstore_preference__e preference);
+
+openapi_petstore_preference__e preference_preference_FromString(char* preference);
+
+cJSON *preference_convertToJSON(openapi_petstore_preference__e preference);
+
+openapi_petstore_preference__e preference_parseFromJSON(cJSON *preferenceJSON);
+
+#endif /* _preference_H_ */
+
diff --git a/samples/client/petstore/c/model/user.c b/samples/client/petstore/c/model/user.c
index eb188153ccf..b43d428e1ff 100644
--- a/samples/client/petstore/c/model/user.c
+++ b/samples/client/petstore/c/model/user.c
@@ -13,7 +13,9 @@ user_t *user_create(
     char *email,
     char *password,
     char *phone,
-    int user_status
+    int user_status,
+    list_t* extra,
+    openapi_petstore_preference__e preference
     ) {
     user_t *user_local_var = malloc(sizeof(user_t));
     if (!user_local_var) {
@@ -27,6 +29,8 @@ user_t *user_create(
     user_local_var->password = password;
     user_local_var->phone = phone;
     user_local_var->user_status = user_status;
+    user_local_var->extra = extra;
+    user_local_var->preference = preference;
 
     return user_local_var;
 }
@@ -61,6 +65,16 @@ void user_free(user_t *user) {
         free(user->phone);
         user->phone = NULL;
     }
+    if (user->extra) {
+        list_ForEach(listEntry, user->extra) {
+            keyValuePair_t *localKeyValue = (keyValuePair_t*) listEntry->data;
+            free (localKeyValue->key);
+            free (localKeyValue->value);
+            keyValuePair_free(localKeyValue);
+        }
+        list_freeList(user->extra);
+        user->extra = NULL;
+    }
     free(user);
 }
 
@@ -130,6 +144,35 @@ cJSON *user_convertToJSON(user_t *user) {
     }
     }
 
+
+    // user->extra
+    if(user->extra) {
+    cJSON *extra = cJSON_AddObjectToObject(item, "extra");
+    if(extra == NULL) {
+        goto fail; //primitive map container
+    }
+    cJSON *localMapObject = extra;
+    listEntry_t *extraListEntry;
+    if (user->extra) {
+    list_ForEach(extraListEntry, user->extra) {
+        keyValuePair_t *localKeyValue = (keyValuePair_t*)extraListEntry->data;
+    }
+    }
+    }
+
+
+    // user->preference
+    if(user->preference != openapi_petstore_preference__NULL) {
+    cJSON *preference_local_JSON = preference_convertToJSON(user->preference);
+    if(preference_local_JSON == NULL) {
+        goto fail; // custom
+    }
+    cJSON_AddItemToObject(item, "preference", preference_local_JSON);
+    if(item->child == NULL) {
+        goto fail;
+    }
+    }
+
     return item;
 fail:
     if (item) {
@@ -142,6 +185,12 @@ user_t *user_parseFromJSON(cJSON *userJSON){
 
     user_t *user_local_var = NULL;
 
+    // define the local map for user->extra
+    list_t *extraList = NULL;
+
+    // define the local variable for user->preference
+    openapi_petstore_preference__e preference_local_nonprim = 0;
+
     // user->id
     cJSON *id = cJSON_GetObjectItemCaseSensitive(userJSON, "id");
     if (id) { 
@@ -214,6 +263,32 @@ user_t *user_parseFromJSON(cJSON *userJSON){
     }
     }
 
+    // user->extra
+    cJSON *extra = cJSON_GetObjectItemCaseSensitive(userJSON, "extra");
+    if (extra) { 
+    cJSON *extra_local_map = NULL;
+    if(!cJSON_IsObject(extra) && !cJSON_IsNull(extra))
+    {
+        goto end;//primitive map container
+    }
+    if(cJSON_IsObject(extra))
+    {
+        extraList = list_createList();
+        keyValuePair_t *localMapKeyPair;
+        cJSON_ArrayForEach(extra_local_map, extra)
+        {
+            cJSON *localMapObject = extra_local_map;
+            list_addElement(extraList , localMapKeyPair);
+        }
+    }
+    }
+
+    // user->preference
+    cJSON *preference = cJSON_GetObjectItemCaseSensitive(userJSON, "preference");
+    if (preference) { 
+    preference_local_nonprim = preference_parseFromJSON(preference); //custom
+    }
+
 
     user_local_var = user_create (
         id ? id->valuedouble : 0,
@@ -223,11 +298,28 @@ user_t *user_parseFromJSON(cJSON *userJSON){
         email && !cJSON_IsNull(email) ? strdup(email->valuestring) : NULL,
         password && !cJSON_IsNull(password) ? strdup(password->valuestring) : NULL,
         phone && !cJSON_IsNull(phone) ? strdup(phone->valuestring) : NULL,
-        user_status ? user_status->valuedouble : 0
+        user_status ? user_status->valuedouble : 0,
+        extra ? extraList : NULL,
+        preference ? preference_local_nonprim : 0
         );
 
     return user_local_var;
 end:
+    if (extraList) {
+        listEntry_t *listEntry = NULL;
+        list_ForEach(listEntry, extraList) {
+            keyValuePair_t *localKeyValue = (keyValuePair_t*) listEntry->data;
+            free(localKeyValue->key);
+            localKeyValue->key = NULL;
+            keyValuePair_free(localKeyValue);
+            localKeyValue = NULL;
+        }
+        list_freeList(extraList);
+        extraList = NULL;
+    }
+    if (preference_local_nonprim) {
+        preference_local_nonprim = 0;
+    }
     return NULL;
 
 }
diff --git a/samples/client/petstore/c/model/user.h b/samples/client/petstore/c/model/user.h
index 45fa42c3f91..badbc747b30 100644
--- a/samples/client/petstore/c/model/user.h
+++ b/samples/client/petstore/c/model/user.h
@@ -15,6 +15,8 @@
 
 typedef struct user_t user_t;
 
+#include "any_type.h"
+#include "preference.h"
 
 
 
@@ -27,6 +29,8 @@ typedef struct user_t {
     char *password; // string
     char *phone; // string
     int user_status; //numeric
+    list_t* extra; //map
+    openapi_petstore_preference__e preference; //referenced enum
 
 } user_t;
 
@@ -38,7 +42,9 @@ user_t *user_create(
     char *email,
     char *password,
     char *phone,
-    int user_status
+    int user_status,
+    list_t* extra,
+    openapi_petstore_preference__e preference
 );
 
 void user_free(user_t *user);
diff --git a/samples/client/petstore/c/unit-test/test_preference.c b/samples/client/petstore/c/unit-test/test_preference.c
new file mode 100644
index 00000000000..8b1e2163fb3
--- /dev/null
+++ b/samples/client/petstore/c/unit-test/test_preference.c
@@ -0,0 +1,56 @@
+#ifndef preference_TEST
+#define preference_TEST
+
+// the following is to include only the main from the first c file
+#ifndef TEST_MAIN
+#define TEST_MAIN
+#define preference_MAIN
+#endif // TEST_MAIN
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include "../external/cJSON.h"
+
+#include "../model/preference.h"
+preference_t* instantiate_preference(int include_optional);
+
+
+
+preference_t* instantiate_preference(int include_optional) {
+  preference_t* preference = NULL;
+  if (include_optional) {
+    preference = preference_create(
+    );
+  } else {
+    preference = preference_create(
+    );
+  }
+
+  return preference;
+}
+
+
+#ifdef preference_MAIN
+
+void test_preference(int include_optional) {
+    preference_t* preference_1 = instantiate_preference(include_optional);
+
+	cJSON* jsonpreference_1 = preference_convertToJSON(preference_1);
+	printf("preference :\n%s\n", cJSON_Print(jsonpreference_1));
+	preference_t* preference_2 = preference_parseFromJSON(jsonpreference_1);
+	cJSON* jsonpreference_2 = preference_convertToJSON(preference_2);
+	printf("repeating preference:\n%s\n", cJSON_Print(jsonpreference_2));
+}
+
+int main() {
+  test_preference(1);
+  test_preference(0);
+
+  printf("Hello world \n");
+  return 0;
+}
+
+#endif // preference_MAIN
+#endif // preference_TEST