diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/vertx/apiImpl.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/vertx/apiImpl.mustache
index 35daaade98f2..e655ccf68c8b 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/vertx/apiImpl.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/vertx/apiImpl.mustache
@@ -112,7 +112,7 @@ public class {{classname}}Impl implements {{classname}} {
 
     private String encodeParameter(String parameter) {
         try {
-            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name());
+            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name()).replaceAll("\\+", "%20");
         } catch (UnsupportedEncodingException e) {
             return parameter;
         }
diff --git a/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/AnotherFakeApiImpl.java b/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/AnotherFakeApiImpl.java
index a2b70fb145fe..e65ab0cd27ee 100644
--- a/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/AnotherFakeApiImpl.java
+++ b/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/AnotherFakeApiImpl.java
@@ -102,7 +102,7 @@ public void call123testSpecialTags(UUID uuidTest, Client body, ApiClient.AuthInf
 
     private String encodeParameter(String parameter) {
         try {
-            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name());
+            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name()).replaceAll("\\+", "%20");
         } catch (UnsupportedEncodingException e) {
             return parameter;
         }
diff --git a/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/FakeApiImpl.java b/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/FakeApiImpl.java
index 3e9d828c5176..22617c63370b 100644
--- a/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/FakeApiImpl.java
+++ b/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/FakeApiImpl.java
@@ -861,7 +861,7 @@ public void testQueryParameterCollectionFormat(List<String> pipe, List<String> i
 
     private String encodeParameter(String parameter) {
         try {
-            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name());
+            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name()).replaceAll("\\+", "%20");
         } catch (UnsupportedEncodingException e) {
             return parameter;
         }
diff --git a/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/FakeClassnameTags123ApiImpl.java b/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/FakeClassnameTags123ApiImpl.java
index 52db1592b67b..9dd50f9abec7 100644
--- a/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/FakeClassnameTags123ApiImpl.java
+++ b/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/FakeClassnameTags123ApiImpl.java
@@ -91,7 +91,7 @@ public void testClassname(Client body, ApiClient.AuthInfo authInfo, Handler<Asyn
 
     private String encodeParameter(String parameter) {
         try {
-            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name());
+            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name()).replaceAll("\\+", "%20");
         } catch (UnsupportedEncodingException e) {
             return parameter;
         }
diff --git a/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/PetApiImpl.java b/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/PetApiImpl.java
index db6d8d66e3e4..80842d1205e2 100644
--- a/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/PetApiImpl.java
+++ b/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/PetApiImpl.java
@@ -508,7 +508,7 @@ public void uploadFileWithRequiredFile(Long petId, AsyncFile requiredFile, Strin
 
     private String encodeParameter(String parameter) {
         try {
-            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name());
+            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name()).replaceAll("\\+", "%20");
         } catch (UnsupportedEncodingException e) {
             return parameter;
         }
diff --git a/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/StoreApiImpl.java b/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/StoreApiImpl.java
index a8a3b7f79fa4..60d79e69f783 100644
--- a/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/StoreApiImpl.java
+++ b/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/StoreApiImpl.java
@@ -227,7 +227,7 @@ public void placeOrder(Order body, ApiClient.AuthInfo authInfo, Handler<AsyncRes
 
     private String encodeParameter(String parameter) {
         try {
-            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name());
+            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name()).replaceAll("\\+", "%20");
         } catch (UnsupportedEncodingException e) {
             return parameter;
         }
diff --git a/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/UserApiImpl.java b/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/UserApiImpl.java
index dfcbfbb6955a..02f78a7fba2c 100644
--- a/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/UserApiImpl.java
+++ b/samples/client/petstore/java/vertx-no-nullable/src/main/java/org/openapitools/client/api/UserApiImpl.java
@@ -438,7 +438,7 @@ public void updateUser(String username, User body, ApiClient.AuthInfo authInfo,
 
     private String encodeParameter(String parameter) {
         try {
-            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name());
+            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name()).replaceAll("\\+", "%20");
         } catch (UnsupportedEncodingException e) {
             return parameter;
         }
diff --git a/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/AnotherFakeApiImpl.java b/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/AnotherFakeApiImpl.java
index 1e8aa2648ca8..e6c5ecba94f2 100644
--- a/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/AnotherFakeApiImpl.java
+++ b/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/AnotherFakeApiImpl.java
@@ -91,7 +91,7 @@ public void call123testSpecialTags(Client client, ApiClient.AuthInfo authInfo, H
 
     private String encodeParameter(String parameter) {
         try {
-            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name());
+            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name()).replaceAll("\\+", "%20");
         } catch (UnsupportedEncodingException e) {
             return parameter;
         }
diff --git a/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/DefaultApiImpl.java b/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/DefaultApiImpl.java
index 12c3ced77d75..6ff8613f266e 100644
--- a/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/DefaultApiImpl.java
+++ b/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/DefaultApiImpl.java
@@ -83,7 +83,7 @@ public void fooGet(ApiClient.AuthInfo authInfo, Handler<AsyncResult<FooGetDefaul
 
     private String encodeParameter(String parameter) {
         try {
-            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name());
+            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name()).replaceAll("\\+", "%20");
         } catch (UnsupportedEncodingException e) {
             return parameter;
         }
diff --git a/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/FakeApiImpl.java b/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/FakeApiImpl.java
index c8b96dda8296..1f1203a266c1 100644
--- a/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/FakeApiImpl.java
+++ b/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/FakeApiImpl.java
@@ -1257,7 +1257,7 @@ public void testStringMapReference(Map<String, String> requestBody, ApiClient.Au
 
     private String encodeParameter(String parameter) {
         try {
-            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name());
+            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name()).replaceAll("\\+", "%20");
         } catch (UnsupportedEncodingException e) {
             return parameter;
         }
diff --git a/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/FakeClassnameTags123ApiImpl.java b/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/FakeClassnameTags123ApiImpl.java
index 19822e2f386b..1fb162078779 100644
--- a/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/FakeClassnameTags123ApiImpl.java
+++ b/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/FakeClassnameTags123ApiImpl.java
@@ -91,7 +91,7 @@ public void testClassname(Client client, ApiClient.AuthInfo authInfo, Handler<As
 
     private String encodeParameter(String parameter) {
         try {
-            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name());
+            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name()).replaceAll("\\+", "%20");
         } catch (UnsupportedEncodingException e) {
             return parameter;
         }
diff --git a/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/PetApiImpl.java b/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/PetApiImpl.java
index 2717a717786a..f7fac0c26f54 100644
--- a/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/PetApiImpl.java
+++ b/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/PetApiImpl.java
@@ -508,7 +508,7 @@ public void uploadFileWithRequiredFile(Long petId, AsyncFile requiredFile, Strin
 
     private String encodeParameter(String parameter) {
         try {
-            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name());
+            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name()).replaceAll("\\+", "%20");
         } catch (UnsupportedEncodingException e) {
             return parameter;
         }
diff --git a/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/StoreApiImpl.java b/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/StoreApiImpl.java
index 9ac8e43f90bd..4462cec686e6 100644
--- a/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/StoreApiImpl.java
+++ b/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/StoreApiImpl.java
@@ -227,7 +227,7 @@ public void placeOrder(Order order, ApiClient.AuthInfo authInfo, Handler<AsyncRe
 
     private String encodeParameter(String parameter) {
         try {
-            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name());
+            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name()).replaceAll("\\+", "%20");
         } catch (UnsupportedEncodingException e) {
             return parameter;
         }
diff --git a/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/UserApiImpl.java b/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/UserApiImpl.java
index 868d85c90f1a..bf8331b0076b 100644
--- a/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/UserApiImpl.java
+++ b/samples/client/petstore/java/vertx-supportVertxFuture/src/main/java/org/openapitools/client/api/UserApiImpl.java
@@ -438,7 +438,7 @@ public void updateUser(String username, User user, ApiClient.AuthInfo authInfo,
 
     private String encodeParameter(String parameter) {
         try {
-            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name());
+            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name()).replaceAll("\\+", "%20");
         } catch (UnsupportedEncodingException e) {
             return parameter;
         }
diff --git a/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/AnotherFakeApiImpl.java b/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/AnotherFakeApiImpl.java
index 1e8aa2648ca8..e6c5ecba94f2 100644
--- a/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/AnotherFakeApiImpl.java
+++ b/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/AnotherFakeApiImpl.java
@@ -91,7 +91,7 @@ public void call123testSpecialTags(Client client, ApiClient.AuthInfo authInfo, H
 
     private String encodeParameter(String parameter) {
         try {
-            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name());
+            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name()).replaceAll("\\+", "%20");
         } catch (UnsupportedEncodingException e) {
             return parameter;
         }
diff --git a/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/DefaultApiImpl.java b/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/DefaultApiImpl.java
index 12c3ced77d75..6ff8613f266e 100644
--- a/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/DefaultApiImpl.java
+++ b/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/DefaultApiImpl.java
@@ -83,7 +83,7 @@ public void fooGet(ApiClient.AuthInfo authInfo, Handler<AsyncResult<FooGetDefaul
 
     private String encodeParameter(String parameter) {
         try {
-            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name());
+            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name()).replaceAll("\\+", "%20");
         } catch (UnsupportedEncodingException e) {
             return parameter;
         }
diff --git a/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/FakeApiImpl.java b/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/FakeApiImpl.java
index c8b96dda8296..1f1203a266c1 100644
--- a/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/FakeApiImpl.java
+++ b/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/FakeApiImpl.java
@@ -1257,7 +1257,7 @@ public void testStringMapReference(Map<String, String> requestBody, ApiClient.Au
 
     private String encodeParameter(String parameter) {
         try {
-            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name());
+            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name()).replaceAll("\\+", "%20");
         } catch (UnsupportedEncodingException e) {
             return parameter;
         }
diff --git a/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/FakeClassnameTags123ApiImpl.java b/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/FakeClassnameTags123ApiImpl.java
index 19822e2f386b..1fb162078779 100644
--- a/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/FakeClassnameTags123ApiImpl.java
+++ b/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/FakeClassnameTags123ApiImpl.java
@@ -91,7 +91,7 @@ public void testClassname(Client client, ApiClient.AuthInfo authInfo, Handler<As
 
     private String encodeParameter(String parameter) {
         try {
-            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name());
+            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name()).replaceAll("\\+", "%20");
         } catch (UnsupportedEncodingException e) {
             return parameter;
         }
diff --git a/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/PetApiImpl.java b/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/PetApiImpl.java
index 2717a717786a..f7fac0c26f54 100644
--- a/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/PetApiImpl.java
+++ b/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/PetApiImpl.java
@@ -508,7 +508,7 @@ public void uploadFileWithRequiredFile(Long petId, AsyncFile requiredFile, Strin
 
     private String encodeParameter(String parameter) {
         try {
-            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name());
+            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name()).replaceAll("\\+", "%20");
         } catch (UnsupportedEncodingException e) {
             return parameter;
         }
diff --git a/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/StoreApiImpl.java b/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/StoreApiImpl.java
index 9ac8e43f90bd..4462cec686e6 100644
--- a/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/StoreApiImpl.java
+++ b/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/StoreApiImpl.java
@@ -227,7 +227,7 @@ public void placeOrder(Order order, ApiClient.AuthInfo authInfo, Handler<AsyncRe
 
     private String encodeParameter(String parameter) {
         try {
-            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name());
+            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name()).replaceAll("\\+", "%20");
         } catch (UnsupportedEncodingException e) {
             return parameter;
         }
diff --git a/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/UserApiImpl.java b/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/UserApiImpl.java
index 868d85c90f1a..bf8331b0076b 100644
--- a/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/UserApiImpl.java
+++ b/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/UserApiImpl.java
@@ -438,7 +438,7 @@ public void updateUser(String username, User user, ApiClient.AuthInfo authInfo,
 
     private String encodeParameter(String parameter) {
         try {
-            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name());
+            return URLEncoder.encode(parameter, StandardCharsets.UTF_8.name()).replaceAll("\\+", "%20");
         } catch (UnsupportedEncodingException e) {
             return parameter;
         }