diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/ApiClient.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/ApiClient.mustache
index 53dddf3269cd..8ee41220bb6b 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/ApiClient.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/ApiClient.mustache
@@ -987,6 +987,30 @@ public class ApiClient {
     }
     {{/dynamicOperations}}
 
+    /**
+    * Formats the specified free-form query parameters to a list of {@code Pair} objects.
+    *
+    * @param value The free-form query parameters.
+    * @return A list of {@code Pair} objects.
+    */
+    public List<Pair> freeFormParameterToPairs(Object value) {
+        List<Pair> params = new ArrayList<>();
+
+        // preconditions
+        if (value == null || !(value instanceof Map )) {
+            return params;
+        }
+
+        final Map<String, Object> valuesMap = (Map<String, Object>) value;
+
+        for (Map.Entry<String, Object> entry : valuesMap.entrySet()) {
+            params.add(new Pair(entry.getKey(), parameterToString(entry.getValue())));
+        }
+
+        return params;
+    }
+
+
     /**
      * Formats the specified collection path parameter to a string value.
      *
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/api.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/api.mustache
index ada640379e31..96757ed648b9 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/api.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/api.mustache
@@ -169,7 +169,7 @@ public class {{classname}} {
         {{^dynamicOperations}}
         {{#queryParams}}
         if ({{paramName}} != null) {
-            {{#collectionFormat}}localVarCollectionQueryParams.addAll(localVarApiClient.parameterToPairs("{{{.}}}", {{/collectionFormat}}{{^collectionFormat}}localVarQueryParams.addAll(localVarApiClient.parameterToPair({{/collectionFormat}}"{{baseName}}", {{paramName}}));
+            {{#isFreeFormObject}}localVarQueryParams.addAll(localVarApiClient.freeFormParameterToPairs({{paramName}}));{{/isFreeFormObject}}{{^isFreeFormObject}}{{#collectionFormat}}localVarCollectionQueryParams.addAll(localVarApiClient.parameterToPairs("{{{.}}}", {{/collectionFormat}}{{^collectionFormat}}localVarQueryParams.addAll(localVarApiClient.parameterToPair({{/collectionFormat}}"{{baseName}}", {{paramName}}));{{/isFreeFormObject}}
         }
 
         {{/queryParams}}
diff --git a/modules/openapi-generator/src/test/resources/3_0/java/petstore-with-fake-endpoints-models-for-testing-okhttp-gson.yaml b/modules/openapi-generator/src/test/resources/3_0/java/petstore-with-fake-endpoints-models-for-testing-okhttp-gson.yaml
index a0d815dd3556..96e8b57753fa 100644
--- a/modules/openapi-generator/src/test/resources/3_0/java/petstore-with-fake-endpoints-models-for-testing-okhttp-gson.yaml
+++ b/modules/openapi-generator/src/test/resources/3_0/java/petstore-with-fake-endpoints-models-for-testing-okhttp-gson.yaml
@@ -1092,6 +1092,21 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/FreeFormObjectTestClass'
+  /fake/free-form-query-parameters:
+    get:
+      parameters:
+        - in: "query"
+          name: "fixed"
+          schema:
+            type: "string"
+        - in: "query"
+          name: "free-form"
+          schema:
+            type: "object"
+          style: "form"
+      responses:
+        200:
+          description: OK
   /fake/test-query-parameters:
     put:
       tags:
diff --git a/samples/client/echo_api/java/okhttp-gson-user-defined-templates/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/echo_api/java/okhttp-gson-user-defined-templates/src/main/java/org/openapitools/client/ApiClient.java
index a524171d7e1a..75adab6382d3 100644
--- a/samples/client/echo_api/java/okhttp-gson-user-defined-templates/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/echo_api/java/okhttp-gson-user-defined-templates/src/main/java/org/openapitools/client/ApiClient.java
@@ -829,6 +829,30 @@ public List<Pair> parameterToPairs(String collectionFormat, String name, Collect
         return params;
     }
 
+    /**
+    * Formats the specified free-form query parameters to a list of {@code Pair} objects.
+    *
+    * @param value The free-form query parameters.
+    * @return A list of {@code Pair} objects.
+    */
+    public List<Pair> freeFormParameterToPairs(Object value) {
+        List<Pair> params = new ArrayList<>();
+
+        // preconditions
+        if (value == null || !(value instanceof Map )) {
+            return params;
+        }
+
+        final Map<String, Object> valuesMap = (Map<String, Object>) value;
+
+        for (Map.Entry<String, Object> entry : valuesMap.entrySet()) {
+            params.add(new Pair(entry.getKey(), parameterToString(entry.getValue())));
+        }
+
+        return params;
+    }
+
+
     /**
      * Formats the specified collection path parameter to a string value.
      *
diff --git a/samples/client/echo_api/java/okhttp-gson/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/echo_api/java/okhttp-gson/src/main/java/org/openapitools/client/ApiClient.java
index 4df37d3b3d50..00bb047c3555 100644
--- a/samples/client/echo_api/java/okhttp-gson/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/echo_api/java/okhttp-gson/src/main/java/org/openapitools/client/ApiClient.java
@@ -759,6 +759,30 @@ public List<Pair> parameterToPairs(String collectionFormat, String name, Collect
         return params;
     }
 
+    /**
+    * Formats the specified free-form query parameters to a list of {@code Pair} objects.
+    *
+    * @param value The free-form query parameters.
+    * @return A list of {@code Pair} objects.
+    */
+    public List<Pair> freeFormParameterToPairs(Object value) {
+        List<Pair> params = new ArrayList<>();
+
+        // preconditions
+        if (value == null || !(value instanceof Map )) {
+            return params;
+        }
+
+        final Map<String, Object> valuesMap = (Map<String, Object>) value;
+
+        for (Map.Entry<String, Object> entry : valuesMap.entrySet()) {
+            params.add(new Pair(entry.getKey(), parameterToString(entry.getValue())));
+        }
+
+        return params;
+    }
+
+
     /**
      * Formats the specified collection path parameter to a string value.
      *
diff --git a/samples/client/others/java/okhttp-gson-oneOf/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/others/java/okhttp-gson-oneOf/src/main/java/org/openapitools/client/ApiClient.java
index 6dc504682e48..a1670b78fa39 100644
--- a/samples/client/others/java/okhttp-gson-oneOf/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/others/java/okhttp-gson-oneOf/src/main/java/org/openapitools/client/ApiClient.java
@@ -733,6 +733,30 @@ public List<Pair> parameterToPairs(String collectionFormat, String name, Collect
         return params;
     }
 
+    /**
+    * Formats the specified free-form query parameters to a list of {@code Pair} objects.
+    *
+    * @param value The free-form query parameters.
+    * @return A list of {@code Pair} objects.
+    */
+    public List<Pair> freeFormParameterToPairs(Object value) {
+        List<Pair> params = new ArrayList<>();
+
+        // preconditions
+        if (value == null || !(value instanceof Map )) {
+            return params;
+        }
+
+        final Map<String, Object> valuesMap = (Map<String, Object>) value;
+
+        for (Map.Entry<String, Object> entry : valuesMap.entrySet()) {
+            params.add(new Pair(entry.getKey(), parameterToString(entry.getValue())));
+        }
+
+        return params;
+    }
+
+
     /**
      * Formats the specified collection path parameter to a string value.
      *
diff --git a/samples/client/others/java/okhttp-gson-streaming/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/others/java/okhttp-gson-streaming/src/main/java/org/openapitools/client/ApiClient.java
index 8382b35e5de4..e78c407026e8 100644
--- a/samples/client/others/java/okhttp-gson-streaming/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/others/java/okhttp-gson-streaming/src/main/java/org/openapitools/client/ApiClient.java
@@ -733,6 +733,30 @@ public List<Pair> parameterToPairs(String collectionFormat, String name, Collect
         return params;
     }
 
+    /**
+    * Formats the specified free-form query parameters to a list of {@code Pair} objects.
+    *
+    * @param value The free-form query parameters.
+    * @return A list of {@code Pair} objects.
+    */
+    public List<Pair> freeFormParameterToPairs(Object value) {
+        List<Pair> params = new ArrayList<>();
+
+        // preconditions
+        if (value == null || !(value instanceof Map )) {
+            return params;
+        }
+
+        final Map<String, Object> valuesMap = (Map<String, Object>) value;
+
+        for (Map.Entry<String, Object> entry : valuesMap.entrySet()) {
+            params.add(new Pair(entry.getKey(), parameterToString(entry.getValue())));
+        }
+
+        return params;
+    }
+
+
     /**
      * Formats the specified collection path parameter to a string value.
      *
diff --git a/samples/client/petstore/java/okhttp-gson-3.1/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/okhttp-gson-3.1/src/main/java/org/openapitools/client/ApiClient.java
index a524171d7e1a..75adab6382d3 100644
--- a/samples/client/petstore/java/okhttp-gson-3.1/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/okhttp-gson-3.1/src/main/java/org/openapitools/client/ApiClient.java
@@ -829,6 +829,30 @@ public List<Pair> parameterToPairs(String collectionFormat, String name, Collect
         return params;
     }
 
+    /**
+    * Formats the specified free-form query parameters to a list of {@code Pair} objects.
+    *
+    * @param value The free-form query parameters.
+    * @return A list of {@code Pair} objects.
+    */
+    public List<Pair> freeFormParameterToPairs(Object value) {
+        List<Pair> params = new ArrayList<>();
+
+        // preconditions
+        if (value == null || !(value instanceof Map )) {
+            return params;
+        }
+
+        final Map<String, Object> valuesMap = (Map<String, Object>) value;
+
+        for (Map.Entry<String, Object> entry : valuesMap.entrySet()) {
+            params.add(new Pair(entry.getKey(), parameterToString(entry.getValue())));
+        }
+
+        return params;
+    }
+
+
     /**
      * Formats the specified collection path parameter to a string value.
      *
diff --git a/samples/client/petstore/java/okhttp-gson-awsv4signature/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/okhttp-gson-awsv4signature/src/main/java/org/openapitools/client/ApiClient.java
index 4708b9034701..85e6fd1a0d4e 100644
--- a/samples/client/petstore/java/okhttp-gson-awsv4signature/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/okhttp-gson-awsv4signature/src/main/java/org/openapitools/client/ApiClient.java
@@ -849,6 +849,30 @@ public List<Pair> parameterToPairs(String collectionFormat, String name, Collect
         return params;
     }
 
+    /**
+    * Formats the specified free-form query parameters to a list of {@code Pair} objects.
+    *
+    * @param value The free-form query parameters.
+    * @return A list of {@code Pair} objects.
+    */
+    public List<Pair> freeFormParameterToPairs(Object value) {
+        List<Pair> params = new ArrayList<>();
+
+        // preconditions
+        if (value == null || !(value instanceof Map )) {
+            return params;
+        }
+
+        final Map<String, Object> valuesMap = (Map<String, Object>) value;
+
+        for (Map.Entry<String, Object> entry : valuesMap.entrySet()) {
+            params.add(new Pair(entry.getKey(), parameterToString(entry.getValue())));
+        }
+
+        return params;
+    }
+
+
     /**
      * Formats the specified collection path parameter to a string value.
      *
diff --git a/samples/client/petstore/java/okhttp-gson-dynamicOperations/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/okhttp-gson-dynamicOperations/src/main/java/org/openapitools/client/ApiClient.java
index e4443654b300..ac4f471d233a 100644
--- a/samples/client/petstore/java/okhttp-gson-dynamicOperations/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/okhttp-gson-dynamicOperations/src/main/java/org/openapitools/client/ApiClient.java
@@ -834,6 +834,30 @@ public List<Pair> parameterToPairs(Parameter param, Collection value) {
         return params;
     }
 
+    /**
+    * Formats the specified free-form query parameters to a list of {@code Pair} objects.
+    *
+    * @param value The free-form query parameters.
+    * @return A list of {@code Pair} objects.
+    */
+    public List<Pair> freeFormParameterToPairs(Object value) {
+        List<Pair> params = new ArrayList<>();
+
+        // preconditions
+        if (value == null || !(value instanceof Map )) {
+            return params;
+        }
+
+        final Map<String, Object> valuesMap = (Map<String, Object>) value;
+
+        for (Map.Entry<String, Object> entry : valuesMap.entrySet()) {
+            params.add(new Pair(entry.getKey(), parameterToString(entry.getValue())));
+        }
+
+        return params;
+    }
+
+
     /**
      * Formats the specified collection path parameter to a string value.
      *
diff --git a/samples/client/petstore/java/okhttp-gson-group-parameter/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/okhttp-gson-group-parameter/src/main/java/org/openapitools/client/ApiClient.java
index a524171d7e1a..75adab6382d3 100644
--- a/samples/client/petstore/java/okhttp-gson-group-parameter/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/okhttp-gson-group-parameter/src/main/java/org/openapitools/client/ApiClient.java
@@ -829,6 +829,30 @@ public List<Pair> parameterToPairs(String collectionFormat, String name, Collect
         return params;
     }
 
+    /**
+    * Formats the specified free-form query parameters to a list of {@code Pair} objects.
+    *
+    * @param value The free-form query parameters.
+    * @return A list of {@code Pair} objects.
+    */
+    public List<Pair> freeFormParameterToPairs(Object value) {
+        List<Pair> params = new ArrayList<>();
+
+        // preconditions
+        if (value == null || !(value instanceof Map )) {
+            return params;
+        }
+
+        final Map<String, Object> valuesMap = (Map<String, Object>) value;
+
+        for (Map.Entry<String, Object> entry : valuesMap.entrySet()) {
+            params.add(new Pair(entry.getKey(), parameterToString(entry.getValue())));
+        }
+
+        return params;
+    }
+
+
     /**
      * Formats the specified collection path parameter to a string value.
      *
diff --git a/samples/client/petstore/java/okhttp-gson-nullable-required/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/okhttp-gson-nullable-required/src/main/java/org/openapitools/client/ApiClient.java
index 690c499f5936..75bdda8f2b0f 100644
--- a/samples/client/petstore/java/okhttp-gson-nullable-required/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/okhttp-gson-nullable-required/src/main/java/org/openapitools/client/ApiClient.java
@@ -832,6 +832,30 @@ public List<Pair> parameterToPairs(String collectionFormat, String name, Collect
         return params;
     }
 
+    /**
+    * Formats the specified free-form query parameters to a list of {@code Pair} objects.
+    *
+    * @param value The free-form query parameters.
+    * @return A list of {@code Pair} objects.
+    */
+    public List<Pair> freeFormParameterToPairs(Object value) {
+        List<Pair> params = new ArrayList<>();
+
+        // preconditions
+        if (value == null || !(value instanceof Map )) {
+            return params;
+        }
+
+        final Map<String, Object> valuesMap = (Map<String, Object>) value;
+
+        for (Map.Entry<String, Object> entry : valuesMap.entrySet()) {
+            params.add(new Pair(entry.getKey(), parameterToString(entry.getValue())));
+        }
+
+        return params;
+    }
+
+
     /**
      * Formats the specified collection path parameter to a string value.
      *
diff --git a/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/ApiClient.java
index d16ca42dee12..bd6f2d005730 100644
--- a/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/ApiClient.java
@@ -835,6 +835,30 @@ public List<Pair> parameterToPairs(String collectionFormat, String name, Collect
         return params;
     }
 
+    /**
+    * Formats the specified free-form query parameters to a list of {@code Pair} objects.
+    *
+    * @param value The free-form query parameters.
+    * @return A list of {@code Pair} objects.
+    */
+    public List<Pair> freeFormParameterToPairs(Object value) {
+        List<Pair> params = new ArrayList<>();
+
+        // preconditions
+        if (value == null || !(value instanceof Map )) {
+            return params;
+        }
+
+        final Map<String, Object> valuesMap = (Map<String, Object>) value;
+
+        for (Map.Entry<String, Object> entry : valuesMap.entrySet()) {
+            params.add(new Pair(entry.getKey(), parameterToString(entry.getValue())));
+        }
+
+        return params;
+    }
+
+
     /**
      * Formats the specified collection path parameter to a string value.
      *
diff --git a/samples/client/petstore/java/okhttp-gson-swagger1/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/okhttp-gson-swagger1/src/main/java/org/openapitools/client/ApiClient.java
index a524171d7e1a..75adab6382d3 100644
--- a/samples/client/petstore/java/okhttp-gson-swagger1/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/okhttp-gson-swagger1/src/main/java/org/openapitools/client/ApiClient.java
@@ -829,6 +829,30 @@ public List<Pair> parameterToPairs(String collectionFormat, String name, Collect
         return params;
     }
 
+    /**
+    * Formats the specified free-form query parameters to a list of {@code Pair} objects.
+    *
+    * @param value The free-form query parameters.
+    * @return A list of {@code Pair} objects.
+    */
+    public List<Pair> freeFormParameterToPairs(Object value) {
+        List<Pair> params = new ArrayList<>();
+
+        // preconditions
+        if (value == null || !(value instanceof Map )) {
+            return params;
+        }
+
+        final Map<String, Object> valuesMap = (Map<String, Object>) value;
+
+        for (Map.Entry<String, Object> entry : valuesMap.entrySet()) {
+            params.add(new Pair(entry.getKey(), parameterToString(entry.getValue())));
+        }
+
+        return params;
+    }
+
+
     /**
      * Formats the specified collection path parameter to a string value.
      *
diff --git a/samples/client/petstore/java/okhttp-gson-swagger2/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/okhttp-gson-swagger2/src/main/java/org/openapitools/client/ApiClient.java
index a524171d7e1a..75adab6382d3 100644
--- a/samples/client/petstore/java/okhttp-gson-swagger2/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/okhttp-gson-swagger2/src/main/java/org/openapitools/client/ApiClient.java
@@ -829,6 +829,30 @@ public List<Pair> parameterToPairs(String collectionFormat, String name, Collect
         return params;
     }
 
+    /**
+    * Formats the specified free-form query parameters to a list of {@code Pair} objects.
+    *
+    * @param value The free-form query parameters.
+    * @return A list of {@code Pair} objects.
+    */
+    public List<Pair> freeFormParameterToPairs(Object value) {
+        List<Pair> params = new ArrayList<>();
+
+        // preconditions
+        if (value == null || !(value instanceof Map )) {
+            return params;
+        }
+
+        final Map<String, Object> valuesMap = (Map<String, Object>) value;
+
+        for (Map.Entry<String, Object> entry : valuesMap.entrySet()) {
+            params.add(new Pair(entry.getKey(), parameterToString(entry.getValue())));
+        }
+
+        return params;
+    }
+
+
     /**
      * Formats the specified collection path parameter to a string value.
      *
diff --git a/samples/client/petstore/java/okhttp-gson/README.md b/samples/client/petstore/java/okhttp-gson/README.md
index b609e998c312..9bac3c677333 100644
--- a/samples/client/petstore/java/okhttp-gson/README.md
+++ b/samples/client/petstore/java/okhttp-gson/README.md
@@ -119,6 +119,7 @@ Class | Method | HTTP request | Description
 *AnotherFakeApi* | [**getParameterStringNumber**](docs/AnotherFakeApi.md#getParameterStringNumber) | **GET** /fake/parameter-string-number | parameter string number
 *AnotherFakeApi* | [**nullRequestBody**](docs/AnotherFakeApi.md#nullRequestBody) | **GET** /fake/null-request-body | null request body
 *DefaultApi* | [**fakeAnyOfWIthSameErasureGet**](docs/DefaultApi.md#fakeAnyOfWIthSameErasureGet) | **GET** /fake/anyOfWIthSameErasure | 
+*DefaultApi* | [**fakeFreeFormQueryParametersGet**](docs/DefaultApi.md#fakeFreeFormQueryParametersGet) | **GET** /fake/free-form-query-parameters | 
 *DefaultApi* | [**fakeOneOfWIthSameErasureGet**](docs/DefaultApi.md#fakeOneOfWIthSameErasureGet) | **GET** /fake/oneOfWIthSameErasure | 
 *DefaultApi* | [**fooGet**](docs/DefaultApi.md#fooGet) | **GET** /foo | 
 *FakeApi* | [**fakeGetFreeFormObjectGet**](docs/FakeApi.md#fakeGetFreeFormObjectGet) | **GET** /fake/get-free-form-object | 
diff --git a/samples/client/petstore/java/okhttp-gson/api/openapi.yaml b/samples/client/petstore/java/okhttp-gson/api/openapi.yaml
index 45059a376787..07fd8fae6889 100644
--- a/samples/client/petstore/java/okhttp-gson/api/openapi.yaml
+++ b/samples/client/petstore/java/okhttp-gson/api/openapi.yaml
@@ -1155,6 +1155,28 @@ paths:
       - fake
       x-accepts:
       - application/json
+  /fake/free-form-query-parameters:
+    get:
+      parameters:
+      - explode: true
+        in: query
+        name: fixed
+        required: false
+        schema:
+          type: string
+        style: form
+      - explode: true
+        in: query
+        name: free-form
+        required: false
+        schema:
+          type: object
+        style: form
+      responses:
+        "200":
+          description: OK
+      x-accepts:
+      - application/json
   /fake/test-query-parameters:
     put:
       description: To test the collection format in query parameters
diff --git a/samples/client/petstore/java/okhttp-gson/docs/DefaultApi.md b/samples/client/petstore/java/okhttp-gson/docs/DefaultApi.md
index 2b2cb4f9098c..b0835fc23cf1 100644
--- a/samples/client/petstore/java/okhttp-gson/docs/DefaultApi.md
+++ b/samples/client/petstore/java/okhttp-gson/docs/DefaultApi.md
@@ -5,6 +5,7 @@ All URIs are relative to *http://petstore.swagger.io:80/v2*
 | Method | HTTP request | Description |
 |------------- | ------------- | -------------|
 | [**fakeAnyOfWIthSameErasureGet**](DefaultApi.md#fakeAnyOfWIthSameErasureGet) | **GET** /fake/anyOfWIthSameErasure |  |
+| [**fakeFreeFormQueryParametersGet**](DefaultApi.md#fakeFreeFormQueryParametersGet) | **GET** /fake/free-form-query-parameters |  |
 | [**fakeOneOfWIthSameErasureGet**](DefaultApi.md#fakeOneOfWIthSameErasureGet) | **GET** /fake/oneOfWIthSameErasure |  |
 | [**fooGet**](DefaultApi.md#fooGet) | **GET** /foo |  |
 
@@ -67,6 +68,67 @@ No authorization required
 |-------------|-------------|------------------|
 | **200** | successful response |  -  |
 
+<a id="fakeFreeFormQueryParametersGet"></a>
+# **fakeFreeFormQueryParametersGet**
+> fakeFreeFormQueryParametersGet(fixed, freeForm)
+
+
+
+### Example
+```java
+// Import classes:
+import org.openapitools.client.ApiClient;
+import org.openapitools.client.ApiException;
+import org.openapitools.client.Configuration;
+import org.openapitools.client.models.*;
+import org.openapitools.client.api.DefaultApi;
+
+public class Example {
+  public static void main(String[] args) {
+    ApiClient defaultClient = Configuration.getDefaultApiClient();
+    defaultClient.setBasePath("http://petstore.swagger.io:80/v2");
+
+    DefaultApi apiInstance = new DefaultApi(defaultClient);
+    String fixed = "fixed_example"; // String | 
+    Object freeForm = null; // Object | 
+    try {
+      apiInstance.fakeFreeFormQueryParametersGet(fixed, freeForm);
+    } catch (ApiException e) {
+      System.err.println("Exception when calling DefaultApi#fakeFreeFormQueryParametersGet");
+      System.err.println("Status code: " + e.getCode());
+      System.err.println("Reason: " + e.getResponseBody());
+      System.err.println("Response headers: " + e.getResponseHeaders());
+      e.printStackTrace();
+    }
+  }
+}
+```
+
+### Parameters
+
+| Name | Type | Description  | Notes |
+|------------- | ------------- | ------------- | -------------|
+| **fixed** | **String**|  | [optional] |
+| **freeForm** | [**Object**](.md)|  | [optional] |
+
+### Return type
+
+null (empty response body)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+ - **Content-Type**: Not defined
+ - **Accept**: Not defined
+
+### HTTP response details
+| Status code | Description | Response headers |
+|-------------|-------------|------------------|
+| **200** | OK |  -  |
+
 <a id="fakeOneOfWIthSameErasureGet"></a>
 # **fakeOneOfWIthSameErasureGet**
 > FakeOneOfWIthSameErasureGet200Response fakeOneOfWIthSameErasureGet()
diff --git a/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/ApiClient.java
index d3c3e6d35035..78b793ed6124 100644
--- a/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/ApiClient.java
@@ -903,6 +903,30 @@ public List<Pair> parameterToPairs(String collectionFormat, String name, Collect
         return params;
     }
 
+    /**
+    * Formats the specified free-form query parameters to a list of {@code Pair} objects.
+    *
+    * @param value The free-form query parameters.
+    * @return A list of {@code Pair} objects.
+    */
+    public List<Pair> freeFormParameterToPairs(Object value) {
+        List<Pair> params = new ArrayList<>();
+
+        // preconditions
+        if (value == null || !(value instanceof Map )) {
+            return params;
+        }
+
+        final Map<String, Object> valuesMap = (Map<String, Object>) value;
+
+        for (Map.Entry<String, Object> entry : valuesMap.entrySet()) {
+            params.add(new Pair(entry.getKey(), parameterToString(entry.getValue())));
+        }
+
+        return params;
+    }
+
+
     /**
      * Formats the specified collection path parameter to a string value.
      *
diff --git a/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/api/DefaultApi.java b/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/api/DefaultApi.java
index 6af7c9ef4314..62b6a566f3dc 100644
--- a/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/api/DefaultApi.java
+++ b/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/api/DefaultApi.java
@@ -187,6 +187,130 @@ public okhttp3.Call fakeAnyOfWIthSameErasureGetAsync(final ApiCallback<FakeAnyOf
         localVarApiClient.executeAsync(localVarCall, localVarReturnType, _callback);
         return localVarCall;
     }
+    /**
+     * Build call for fakeFreeFormQueryParametersGet
+     * @param fixed  (optional)
+     * @param freeForm  (optional)
+     * @param _callback Callback for upload/download progress
+     * @return Call to execute
+     * @throws ApiException If fail to serialize the request body object
+     * @http.response.details
+     <table summary="Response Details" border="1">
+        <tr><td> Status Code </td><td> Description </td><td> Response Headers </td></tr>
+        <tr><td> 200 </td><td> OK </td><td>  -  </td></tr>
+     </table>
+     */
+    public okhttp3.Call fakeFreeFormQueryParametersGetCall(String fixed, Object freeForm, final ApiCallback _callback) throws ApiException {
+        String basePath = null;
+        // Operation Servers
+        String[] localBasePaths = new String[] {  };
+
+        // Determine Base Path to Use
+        if (localCustomBaseUrl != null){
+            basePath = localCustomBaseUrl;
+        } else if ( localBasePaths.length > 0 ) {
+            basePath = localBasePaths[localHostIndex];
+        } else {
+            basePath = null;
+        }
+
+        Object localVarPostBody = null;
+
+        // create path and map variables
+        String localVarPath = "/fake/free-form-query-parameters";
+
+        List<Pair> localVarQueryParams = new ArrayList<Pair>();
+        List<Pair> localVarCollectionQueryParams = new ArrayList<Pair>();
+        Map<String, String> localVarHeaderParams = new HashMap<String, String>();
+        Map<String, String> localVarCookieParams = new HashMap<String, String>();
+        Map<String, Object> localVarFormParams = new HashMap<String, Object>();
+
+        if (fixed != null) {
+            localVarQueryParams.addAll(localVarApiClient.parameterToPair("fixed", fixed));
+        }
+
+        if (freeForm != null) {
+            localVarQueryParams.addAll(localVarApiClient.freeFormParameterToPairs(freeForm));
+        }
+
+        final String[] localVarAccepts = {
+        };
+        final String localVarAccept = localVarApiClient.selectHeaderAccept(localVarAccepts);
+        if (localVarAccept != null) {
+            localVarHeaderParams.put("Accept", localVarAccept);
+        }
+
+        final String[] localVarContentTypes = {
+        };
+        final String localVarContentType = localVarApiClient.selectHeaderContentType(localVarContentTypes);
+        if (localVarContentType != null) {
+            localVarHeaderParams.put("Content-Type", localVarContentType);
+        }
+
+        String[] localVarAuthNames = new String[] {  };
+        return localVarApiClient.buildCall(basePath, localVarPath, "GET", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAuthNames, _callback);
+    }
+
+    @SuppressWarnings("rawtypes")
+    private okhttp3.Call fakeFreeFormQueryParametersGetValidateBeforeCall(String fixed, Object freeForm, final ApiCallback _callback) throws ApiException {
+        return fakeFreeFormQueryParametersGetCall(fixed, freeForm, _callback);
+
+    }
+
+    /**
+     * 
+     * 
+     * @param fixed  (optional)
+     * @param freeForm  (optional)
+     * @throws ApiException If fail to call the API, e.g. server error or cannot deserialize the response body
+     * @http.response.details
+     <table summary="Response Details" border="1">
+        <tr><td> Status Code </td><td> Description </td><td> Response Headers </td></tr>
+        <tr><td> 200 </td><td> OK </td><td>  -  </td></tr>
+     </table>
+     */
+    public void fakeFreeFormQueryParametersGet(String fixed, Object freeForm) throws ApiException {
+        fakeFreeFormQueryParametersGetWithHttpInfo(fixed, freeForm);
+    }
+
+    /**
+     * 
+     * 
+     * @param fixed  (optional)
+     * @param freeForm  (optional)
+     * @return ApiResponse&lt;Void&gt;
+     * @throws ApiException If fail to call the API, e.g. server error or cannot deserialize the response body
+     * @http.response.details
+     <table summary="Response Details" border="1">
+        <tr><td> Status Code </td><td> Description </td><td> Response Headers </td></tr>
+        <tr><td> 200 </td><td> OK </td><td>  -  </td></tr>
+     </table>
+     */
+    public ApiResponse<Void> fakeFreeFormQueryParametersGetWithHttpInfo(String fixed, Object freeForm) throws ApiException {
+        okhttp3.Call localVarCall = fakeFreeFormQueryParametersGetValidateBeforeCall(fixed, freeForm, null);
+        return localVarApiClient.execute(localVarCall);
+    }
+
+    /**
+     *  (asynchronously)
+     * 
+     * @param fixed  (optional)
+     * @param freeForm  (optional)
+     * @param _callback The callback to be executed when the API call finishes
+     * @return The request call
+     * @throws ApiException If fail to process the API call, e.g. serializing the request body object
+     * @http.response.details
+     <table summary="Response Details" border="1">
+        <tr><td> Status Code </td><td> Description </td><td> Response Headers </td></tr>
+        <tr><td> 200 </td><td> OK </td><td>  -  </td></tr>
+     </table>
+     */
+    public okhttp3.Call fakeFreeFormQueryParametersGetAsync(String fixed, Object freeForm, final ApiCallback<Void> _callback) throws ApiException {
+
+        okhttp3.Call localVarCall = fakeFreeFormQueryParametersGetValidateBeforeCall(fixed, freeForm, _callback);
+        localVarApiClient.executeAsync(localVarCall, _callback);
+        return localVarCall;
+    }
     /**
      * Build call for fakeOneOfWIthSameErasureGet
      * @param _callback Callback for upload/download progress