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 10121f95da82..d0ee6b629ccb 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
@@ -1426,12 +1426,15 @@ public class ApiClient {
         // prepare HTTP request body
         RequestBody reqBody;
         String contentType = headerParams.get("Content-Type");
-
+        String contentTypePure = contentType;
+        if (contentTypePure != null && contentTypePure.contains(";")) {
+            contentTypePure = contentType.substring(0, contentType.indexOf(";"));
+        }
         if (!HttpMethod.permitsRequestBody(method)) {
             reqBody = null;
-        } else if ("application/x-www-form-urlencoded".equals(contentType)) {
+        } else if ("application/x-www-form-urlencoded".equals(contentTypePure)) {
             reqBody = buildRequestBodyFormEncoding(formParams);
-        } else if ("multipart/form-data".equals(contentType)) {
+        } else if ("multipart/form-data".equals(contentTypePure)) {
             reqBody = buildRequestBodyMultipart(formParams);
         } else if (body == null) {
             if ("DELETE".equals(method)) {
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 e6bcdf0d69b1..8f710611efb4 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
@@ -1166,12 +1166,15 @@ public Request buildRequest(String baseUrl, String path, String method, List<Pai
         // prepare HTTP request body
         RequestBody reqBody;
         String contentType = headerParams.get("Content-Type");
-
+        String contentTypePure = contentType;
+        if (contentTypePure != null && contentTypePure.contains(";")) {
+            contentTypePure = contentType.substring(0, contentType.indexOf(";"));
+        }
         if (!HttpMethod.permitsRequestBody(method)) {
             reqBody = null;
-        } else if ("application/x-www-form-urlencoded".equals(contentType)) {
+        } else if ("application/x-www-form-urlencoded".equals(contentTypePure)) {
             reqBody = buildRequestBodyFormEncoding(formParams);
-        } else if ("multipart/form-data".equals(contentType)) {
+        } else if ("multipart/form-data".equals(contentTypePure)) {
             reqBody = buildRequestBodyMultipart(formParams);
         } else if (body == null) {
             if ("DELETE".equals(method)) {
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 f1c4d5316ba8..b382d2da2c9d 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
@@ -1189,12 +1189,15 @@ public Request buildRequest(String baseUrl, String path, String method, List<Pai
         // prepare HTTP request body
         RequestBody reqBody;
         String contentType = headerParams.get("Content-Type");
-
+        String contentTypePure = contentType;
+        if (contentTypePure != null && contentTypePure.contains(";")) {
+            contentTypePure = contentType.substring(0, contentType.indexOf(";"));
+        }
         if (!HttpMethod.permitsRequestBody(method)) {
             reqBody = null;
-        } else if ("application/x-www-form-urlencoded".equals(contentType)) {
+        } else if ("application/x-www-form-urlencoded".equals(contentTypePure)) {
             reqBody = buildRequestBodyFormEncoding(formParams);
-        } else if ("multipart/form-data".equals(contentType)) {
+        } else if ("multipart/form-data".equals(contentTypePure)) {
             reqBody = buildRequestBodyMultipart(formParams);
         } else if (body == null) {
             if ("DELETE".equals(method)) {
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 46f938398914..21ac39664037 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
@@ -1274,12 +1274,15 @@ public Request buildRequest(String baseUrl, String path, String method, List<Pai
         // prepare HTTP request body
         RequestBody reqBody;
         String contentType = headerParams.get("Content-Type");
-
+        String contentTypePure = contentType;
+        if (contentTypePure != null && contentTypePure.contains(";")) {
+            contentTypePure = contentType.substring(0, contentType.indexOf(";"));
+        }
         if (!HttpMethod.permitsRequestBody(method)) {
             reqBody = null;
-        } else if ("application/x-www-form-urlencoded".equals(contentType)) {
+        } else if ("application/x-www-form-urlencoded".equals(contentTypePure)) {
             reqBody = buildRequestBodyFormEncoding(formParams);
-        } else if ("multipart/form-data".equals(contentType)) {
+        } else if ("multipart/form-data".equals(contentTypePure)) {
             reqBody = buildRequestBodyMultipart(formParams);
         } else if (body == null) {
             if ("DELETE".equals(method)) {
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 249921761873..3b744150e977 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
@@ -1267,12 +1267,15 @@ public Request buildRequest(String baseUrl, String path, String method, List<Pai
         // prepare HTTP request body
         RequestBody reqBody;
         String contentType = headerParams.get("Content-Type");
-
+        String contentTypePure = contentType;
+        if (contentTypePure != null && contentTypePure.contains(";")) {
+            contentTypePure = contentType.substring(0, contentType.indexOf(";"));
+        }
         if (!HttpMethod.permitsRequestBody(method)) {
             reqBody = null;
-        } else if ("application/x-www-form-urlencoded".equals(contentType)) {
+        } else if ("application/x-www-form-urlencoded".equals(contentTypePure)) {
             reqBody = buildRequestBodyFormEncoding(formParams);
-        } else if ("multipart/form-data".equals(contentType)) {
+        } else if ("multipart/form-data".equals(contentTypePure)) {
             reqBody = buildRequestBodyMultipart(formParams);
         } else if (body == null) {
             if ("DELETE".equals(method)) {
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 0c89459d8b69..6d1cc62db7e7 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
@@ -1262,12 +1262,15 @@ public Request buildRequest(String baseUrl, String path, String method, List<Pai
         // prepare HTTP request body
         RequestBody reqBody;
         String contentType = headerParams.get("Content-Type");
-
+        String contentTypePure = contentType;
+        if (contentTypePure != null && contentTypePure.contains(";")) {
+            contentTypePure = contentType.substring(0, contentType.indexOf(";"));
+        }
         if (!HttpMethod.permitsRequestBody(method)) {
             reqBody = null;
-        } else if ("application/x-www-form-urlencoded".equals(contentType)) {
+        } else if ("application/x-www-form-urlencoded".equals(contentTypePure)) {
             reqBody = buildRequestBodyFormEncoding(formParams);
-        } else if ("multipart/form-data".equals(contentType)) {
+        } else if ("multipart/form-data".equals(contentTypePure)) {
             reqBody = buildRequestBodyMultipart(formParams);
         } else if (body == null) {
             if ("DELETE".equals(method)) {
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 295e204544ca..3f95f4861622 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
@@ -1265,12 +1265,15 @@ public Request buildRequest(String baseUrl, String path, String method, List<Pai
         // prepare HTTP request body
         RequestBody reqBody;
         String contentType = headerParams.get("Content-Type");
-
+        String contentTypePure = contentType;
+        if (contentTypePure != null && contentTypePure.contains(";")) {
+            contentTypePure = contentType.substring(0, contentType.indexOf(";"));
+        }
         if (!HttpMethod.permitsRequestBody(method)) {
             reqBody = null;
-        } else if ("application/x-www-form-urlencoded".equals(contentType)) {
+        } else if ("application/x-www-form-urlencoded".equals(contentTypePure)) {
             reqBody = buildRequestBodyFormEncoding(formParams);
-        } else if ("multipart/form-data".equals(contentType)) {
+        } else if ("multipart/form-data".equals(contentTypePure)) {
             reqBody = buildRequestBodyMultipart(formParams);
         } else if (body == null) {
             if ("DELETE".equals(method)) {
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 a3e03f9c9cff..ccc405823612 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
@@ -1268,12 +1268,15 @@ public Request buildRequest(String baseUrl, String path, String method, List<Pai
         // prepare HTTP request body
         RequestBody reqBody;
         String contentType = headerParams.get("Content-Type");
-
+        String contentTypePure = contentType;
+        if (contentTypePure != null && contentTypePure.contains(";")) {
+            contentTypePure = contentType.substring(0, contentType.indexOf(";"));
+        }
         if (!HttpMethod.permitsRequestBody(method)) {
             reqBody = null;
-        } else if ("application/x-www-form-urlencoded".equals(contentType)) {
+        } else if ("application/x-www-form-urlencoded".equals(contentTypePure)) {
             reqBody = buildRequestBodyFormEncoding(formParams);
-        } else if ("multipart/form-data".equals(contentType)) {
+        } else if ("multipart/form-data".equals(contentTypePure)) {
             reqBody = buildRequestBodyMultipart(formParams);
         } else if (body == null) {
             if ("DELETE".equals(method)) {
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 0c89459d8b69..6d1cc62db7e7 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
@@ -1262,12 +1262,15 @@ public Request buildRequest(String baseUrl, String path, String method, List<Pai
         // prepare HTTP request body
         RequestBody reqBody;
         String contentType = headerParams.get("Content-Type");
-
+        String contentTypePure = contentType;
+        if (contentTypePure != null && contentTypePure.contains(";")) {
+            contentTypePure = contentType.substring(0, contentType.indexOf(";"));
+        }
         if (!HttpMethod.permitsRequestBody(method)) {
             reqBody = null;
-        } else if ("application/x-www-form-urlencoded".equals(contentType)) {
+        } else if ("application/x-www-form-urlencoded".equals(contentTypePure)) {
             reqBody = buildRequestBodyFormEncoding(formParams);
-        } else if ("multipart/form-data".equals(contentType)) {
+        } else if ("multipart/form-data".equals(contentTypePure)) {
             reqBody = buildRequestBodyMultipart(formParams);
         } else if (body == null) {
             if ("DELETE".equals(method)) {
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 0c89459d8b69..6d1cc62db7e7 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
@@ -1262,12 +1262,15 @@ public Request buildRequest(String baseUrl, String path, String method, List<Pai
         // prepare HTTP request body
         RequestBody reqBody;
         String contentType = headerParams.get("Content-Type");
-
+        String contentTypePure = contentType;
+        if (contentTypePure != null && contentTypePure.contains(";")) {
+            contentTypePure = contentType.substring(0, contentType.indexOf(";"));
+        }
         if (!HttpMethod.permitsRequestBody(method)) {
             reqBody = null;
-        } else if ("application/x-www-form-urlencoded".equals(contentType)) {
+        } else if ("application/x-www-form-urlencoded".equals(contentTypePure)) {
             reqBody = buildRequestBodyFormEncoding(formParams);
-        } else if ("multipart/form-data".equals(contentType)) {
+        } else if ("multipart/form-data".equals(contentTypePure)) {
             reqBody = buildRequestBodyMultipart(formParams);
         } else if (body == null) {
             if ("DELETE".equals(method)) {
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 147996f875db..8593e66829db 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
@@ -1327,12 +1327,15 @@ public Request buildRequest(String baseUrl, String path, String method, List<Pai
         // prepare HTTP request body
         RequestBody reqBody;
         String contentType = headerParams.get("Content-Type");
-
+        String contentTypePure = contentType;
+        if (contentTypePure != null && contentTypePure.contains(";")) {
+            contentTypePure = contentType.substring(0, contentType.indexOf(";"));
+        }
         if (!HttpMethod.permitsRequestBody(method)) {
             reqBody = null;
-        } else if ("application/x-www-form-urlencoded".equals(contentType)) {
+        } else if ("application/x-www-form-urlencoded".equals(contentTypePure)) {
             reqBody = buildRequestBodyFormEncoding(formParams);
-        } else if ("multipart/form-data".equals(contentType)) {
+        } else if ("multipart/form-data".equals(contentTypePure)) {
             reqBody = buildRequestBodyMultipart(formParams);
         } else if (body == null) {
             if ("DELETE".equals(method)) {