diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/apache-httpclient/ApiClient.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/apache-httpclient/ApiClient.mustache
index 0661db1e0ce8..854d8a6cd9af 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/apache-httpclient/ApiClient.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/apache-httpclient/ApiClient.mustache
@@ -444,7 +444,7 @@ public class ApiClient{{#jsr310}} extends JavaTimeFormatter{{/jsr310}} {
    * @param userAgent User agent
    * @return API client
    */
-  public ApiClient setUserAgent(String userAgent) {
+  public final ApiClient setUserAgent(String userAgent) {
     addDefaultHeader("User-Agent", userAgent);
     return this;
   }
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/native/ApiClient.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/native/ApiClient.mustache
index 730e975f7390..a8bede35507c 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/native/ApiClient.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/native/ApiClient.mustache
@@ -207,7 +207,7 @@ public class ApiClient {
     return HttpClient.newBuilder();
   }
 
-  public void updateBaseUri(String baseUri) {
+  public final void updateBaseUri(String baseUri) {
     URI uri = URI.create(baseUri);
     scheme = uri.getScheme();
     host = uri.getHost();
diff --git a/samples/client/echo_api/java/apache-httpclient/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/echo_api/java/apache-httpclient/src/main/java/org/openapitools/client/ApiClient.java
index 0cb6e8752cf9..790a5abb4bbe 100644
--- a/samples/client/echo_api/java/apache-httpclient/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/echo_api/java/apache-httpclient/src/main/java/org/openapitools/client/ApiClient.java
@@ -362,7 +362,7 @@ public ApiClient setPassword(String password) {
    * @param userAgent User agent
    * @return API client
    */
-  public ApiClient setUserAgent(String userAgent) {
+  public final ApiClient setUserAgent(String userAgent) {
     addDefaultHeader("User-Agent", userAgent);
     return this;
   }
diff --git a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/ApiClient.java
index 96f20b81867f..3d56f0aec841 100644
--- a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/ApiClient.java
@@ -214,7 +214,7 @@ public static HttpClient.Builder createDefaultHttpClientBuilder() {
     return HttpClient.newBuilder();
   }
 
-  public void updateBaseUri(String baseUri) {
+  public final void updateBaseUri(String baseUri) {
     URI uri = URI.create(baseUri);
     scheme = uri.getScheme();
     host = uri.getHost();
diff --git a/samples/client/petstore/java/apache-httpclient/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/apache-httpclient/src/main/java/org/openapitools/client/ApiClient.java
index e3d2130be93b..6d3f3bbcac87 100644
--- a/samples/client/petstore/java/apache-httpclient/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/apache-httpclient/src/main/java/org/openapitools/client/ApiClient.java
@@ -455,7 +455,7 @@ public ApiClient setAccessToken(String accessToken) {
    * @param userAgent User agent
    * @return API client
    */
-  public ApiClient setUserAgent(String userAgent) {
+  public final ApiClient setUserAgent(String userAgent) {
     addDefaultHeader("User-Agent", userAgent);
     return this;
   }
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/ApiClient.java
index 261cbe1e06f8..642ff1194ca3 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/ApiClient.java
@@ -214,7 +214,7 @@ public static HttpClient.Builder createDefaultHttpClientBuilder() {
     return HttpClient.newBuilder();
   }
 
-  public void updateBaseUri(String baseUri) {
+  public final void updateBaseUri(String baseUri) {
     URI uri = URI.create(baseUri);
     scheme = uri.getScheme();
     host = uri.getHost();
diff --git a/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/ApiClient.java
index 28c477f8407d..6e57722f0337 100644
--- a/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/ApiClient.java
@@ -214,7 +214,7 @@ public static HttpClient.Builder createDefaultHttpClientBuilder() {
     return HttpClient.newBuilder();
   }
 
-  public void updateBaseUri(String baseUri) {
+  public final void updateBaseUri(String baseUri) {
     URI uri = URI.create(baseUri);
     scheme = uri.getScheme();
     host = uri.getHost();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/ApiClient.java
index 261cbe1e06f8..642ff1194ca3 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/ApiClient.java
@@ -214,7 +214,7 @@ public static HttpClient.Builder createDefaultHttpClientBuilder() {
     return HttpClient.newBuilder();
   }
 
-  public void updateBaseUri(String baseUri) {
+  public final void updateBaseUri(String baseUri) {
     URI uri = URI.create(baseUri);
     scheme = uri.getScheme();
     host = uri.getHost();