diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaClientCodegen.java
index 26fbbbe4467..eed6c36afaf 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaClientCodegen.java
@@ -855,7 +855,7 @@ public class JavaClientCodegen extends AbstractJavaCodegen
                 // add extension to indicate content type is `text/plain` and the response type is `String`
                 if (op.produces != null) {
                     for (Map<String, String> produce : op.produces) {
-                        if ("text/plain".equalsIgnoreCase(produce.get("mediaType"))
+                        if ("text/plain".equalsIgnoreCase(produce.get("mediaType").split(";")[0].trim())
                                 && "String".equals(op.returnType)) {
                             op.vendorExtensions.put("x-java-text-plain-string", true);
                             continue;
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/native/api.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/native/api.mustache
index f0f6960bfca..756face0ddf 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/native/api.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/native/api.mustache
@@ -255,7 +255,7 @@ public class {{classname}} {
         {{#vendorExtensions.x-java-text-plain-string}}
         // for plain text response
         if (localVarResponse.headers().map().containsKey("Content-Type") &&
-                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0))) {
+                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0).split(";")[0].trim())) {
           java.util.Scanner s = new java.util.Scanner(localVarResponse.body()).useDelimiter("\\A");
           String responseBodyText = s.hasNext() ? s.next() : "";
           return new ApiResponse<String>(
diff --git a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/BodyApi.java b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/BodyApi.java
index 83a43459717..0701d23c041 100644
--- a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/BodyApi.java
+++ b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/BodyApi.java
@@ -182,7 +182,7 @@ public class BodyApi {
         }
         // for plain text response
         if (localVarResponse.headers().map().containsKey("Content-Type") &&
-                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0))) {
+                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0).split(";")[0].trim())) {
           java.util.Scanner s = new java.util.Scanner(localVarResponse.body()).useDelimiter("\\A");
           String responseBodyText = s.hasNext() ? s.next() : "";
           return new ApiResponse<String>(
@@ -263,7 +263,7 @@ public class BodyApi {
         }
         // for plain text response
         if (localVarResponse.headers().map().containsKey("Content-Type") &&
-                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0))) {
+                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0).split(";")[0].trim())) {
           java.util.Scanner s = new java.util.Scanner(localVarResponse.body()).useDelimiter("\\A");
           String responseBodyText = s.hasNext() ? s.next() : "";
           return new ApiResponse<String>(
@@ -417,7 +417,7 @@ public class BodyApi {
         }
         // for plain text response
         if (localVarResponse.headers().map().containsKey("Content-Type") &&
-                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0))) {
+                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0).split(";")[0].trim())) {
           java.util.Scanner s = new java.util.Scanner(localVarResponse.body()).useDelimiter("\\A");
           String responseBodyText = s.hasNext() ? s.next() : "";
           return new ApiResponse<String>(
@@ -498,7 +498,7 @@ public class BodyApi {
         }
         // for plain text response
         if (localVarResponse.headers().map().containsKey("Content-Type") &&
-                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0))) {
+                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0).split(";")[0].trim())) {
           java.util.Scanner s = new java.util.Scanner(localVarResponse.body()).useDelimiter("\\A");
           String responseBodyText = s.hasNext() ? s.next() : "";
           return new ApiResponse<String>(
diff --git a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/FormApi.java b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/FormApi.java
index 5ea2af146b2..c6e033ec70b 100644
--- a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/FormApi.java
+++ b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/FormApi.java
@@ -124,7 +124,7 @@ public class FormApi {
         }
         // for plain text response
         if (localVarResponse.headers().map().containsKey("Content-Type") &&
-                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0))) {
+                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0).split(";")[0].trim())) {
           java.util.Scanner s = new java.util.Scanner(localVarResponse.body()).useDelimiter("\\A");
           String responseBodyText = s.hasNext() ? s.next() : "";
           return new ApiResponse<String>(
diff --git a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/HeaderApi.java b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/HeaderApi.java
index 8961d5735d2..41489410a41 100644
--- a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/HeaderApi.java
+++ b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/HeaderApi.java
@@ -124,7 +124,7 @@ public class HeaderApi {
         }
         // for plain text response
         if (localVarResponse.headers().map().containsKey("Content-Type") &&
-                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0))) {
+                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0).split(";")[0].trim())) {
           java.util.Scanner s = new java.util.Scanner(localVarResponse.body()).useDelimiter("\\A");
           String responseBodyText = s.hasNext() ? s.next() : "";
           return new ApiResponse<String>(
diff --git a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/PathApi.java b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/PathApi.java
index c34fe234ac0..8e5db91279d 100644
--- a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/PathApi.java
+++ b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/PathApi.java
@@ -122,7 +122,7 @@ public class PathApi {
         }
         // for plain text response
         if (localVarResponse.headers().map().containsKey("Content-Type") &&
-                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0))) {
+                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0).split(";")[0].trim())) {
           java.util.Scanner s = new java.util.Scanner(localVarResponse.body()).useDelimiter("\\A");
           String responseBodyText = s.hasNext() ? s.next() : "";
           return new ApiResponse<String>(
diff --git a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/QueryApi.java b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/QueryApi.java
index 4ce18c3ab72..2aed49d3080 100644
--- a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/QueryApi.java
+++ b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/QueryApi.java
@@ -127,7 +127,7 @@ public class QueryApi {
         }
         // for plain text response
         if (localVarResponse.headers().map().containsKey("Content-Type") &&
-                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0))) {
+                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0).split(";")[0].trim())) {
           java.util.Scanner s = new java.util.Scanner(localVarResponse.body()).useDelimiter("\\A");
           String responseBodyText = s.hasNext() ? s.next() : "";
           return new ApiResponse<String>(
@@ -221,7 +221,7 @@ public class QueryApi {
         }
         // for plain text response
         if (localVarResponse.headers().map().containsKey("Content-Type") &&
-                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0))) {
+                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0).split(";")[0].trim())) {
           java.util.Scanner s = new java.util.Scanner(localVarResponse.body()).useDelimiter("\\A");
           String responseBodyText = s.hasNext() ? s.next() : "";
           return new ApiResponse<String>(
@@ -319,7 +319,7 @@ public class QueryApi {
         }
         // for plain text response
         if (localVarResponse.headers().map().containsKey("Content-Type") &&
-                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0))) {
+                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0).split(";")[0].trim())) {
           java.util.Scanner s = new java.util.Scanner(localVarResponse.body()).useDelimiter("\\A");
           String responseBodyText = s.hasNext() ? s.next() : "";
           return new ApiResponse<String>(
@@ -413,7 +413,7 @@ public class QueryApi {
         }
         // for plain text response
         if (localVarResponse.headers().map().containsKey("Content-Type") &&
-                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0))) {
+                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0).split(";")[0].trim())) {
           java.util.Scanner s = new java.util.Scanner(localVarResponse.body()).useDelimiter("\\A");
           String responseBodyText = s.hasNext() ? s.next() : "";
           return new ApiResponse<String>(
@@ -505,7 +505,7 @@ public class QueryApi {
         }
         // for plain text response
         if (localVarResponse.headers().map().containsKey("Content-Type") &&
-                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0))) {
+                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0).split(";")[0].trim())) {
           java.util.Scanner s = new java.util.Scanner(localVarResponse.body()).useDelimiter("\\A");
           String responseBodyText = s.hasNext() ? s.next() : "";
           return new ApiResponse<String>(
@@ -597,7 +597,7 @@ public class QueryApi {
         }
         // for plain text response
         if (localVarResponse.headers().map().containsKey("Content-Type") &&
-                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0))) {
+                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0).split(";")[0].trim())) {
           java.util.Scanner s = new java.util.Scanner(localVarResponse.body()).useDelimiter("\\A");
           String responseBodyText = s.hasNext() ? s.next() : "";
           return new ApiResponse<String>(
@@ -687,7 +687,7 @@ public class QueryApi {
         }
         // for plain text response
         if (localVarResponse.headers().map().containsKey("Content-Type") &&
-                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0))) {
+                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0).split(";")[0].trim())) {
           java.util.Scanner s = new java.util.Scanner(localVarResponse.body()).useDelimiter("\\A");
           String responseBodyText = s.hasNext() ? s.next() : "";
           return new ApiResponse<String>(
@@ -782,7 +782,7 @@ public class QueryApi {
         }
         // for plain text response
         if (localVarResponse.headers().map().containsKey("Content-Type") &&
-                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0))) {
+                "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0).split(";")[0].trim())) {
           java.util.Scanner s = new java.util.Scanner(localVarResponse.body()).useDelimiter("\\A");
           String responseBodyText = s.hasNext() ? s.next() : "";
           return new ApiResponse<String>(