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 095a71939a7..ea46db7331d 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
@@ -170,7 +170,7 @@ public class ApiClient {
   public ApiClient(HttpClient.Builder builder, ObjectMapper mapper, String baseUri) {
     this.builder = builder;
     this.mapper = mapper;
-    updateBaseUri(baseUri);
+    updateBaseUri(baseUri != null ? baseUri : getDefaultBaseUri());
     interceptor = null;
     readTimeout = null;
     responseInterceptor = null;
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 2adef3a6b0e..e91e72f97b9 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
@@ -65,6 +65,14 @@ public class {{classname}} {
   }
   {{/asyncNative}}
 
+  protected ApiException createApiException(HttpResponse<InputStream> response, String msgPrefix) throws IOException {
+    String body = response.body() == null ? null : new String(response.body().readAllBytes());
+    if (body != null) {
+      msgPrefix += ": " + body;
+    }
+    return new ApiException(response.statusCode(), msgPrefix, response.headers(), body);
+  }
+
   {{#operation}}
   {{#vendorExtensions.x-group-parameters}}
   {{#hasParams}}
@@ -207,10 +215,7 @@ public class {{classname}} {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "{{operationId}} call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "{{operationId}} call received non-success response");
       }
       return new ApiResponse<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}Void{{/returnType}}>(
           localVarResponse.statusCode(),
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 98cdbf0646b..4b5a1fb4bd3 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
@@ -175,7 +175,7 @@ public class ApiClient {
   public ApiClient(HttpClient.Builder builder, ObjectMapper mapper, String baseUri) {
     this.builder = builder;
     this.mapper = mapper;
-    updateBaseUri(baseUri);
+    updateBaseUri(baseUri != null ? baseUri : getDefaultBaseUri());
     interceptor = null;
     readTimeout = null;
     responseInterceptor = null;
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/AnotherFakeApi.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
index 38c4a321f65..f2247d141bb 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
@@ -67,6 +67,14 @@ public class AnotherFakeApi {
         localVarResponse.body());
   }
 
+  protected ApiException createApiException(HttpResponse<InputStream> response, String msgPrefix) throws IOException {
+    String body = response.body() == null ? null : new String(response.body().readAllBytes());
+    if (body != null) {
+      msgPrefix += ": " + body;
+    }
+    return new ApiException(response.statusCode(), msgPrefix, response.headers(), body);
+  }
+
   /**
    * To test special tags
    * To test special tags and operation ID starting with number
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/FakeApi.java
index 415e6a35a40..388dce55a87 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -75,6 +75,14 @@ public class FakeApi {
         localVarResponse.body());
   }
 
+  protected ApiException createApiException(HttpResponse<InputStream> response, String msgPrefix) throws IOException {
+    String body = response.body() == null ? null : new String(response.body().readAllBytes());
+    if (body != null) {
+      msgPrefix += ": " + body;
+    }
+    return new ApiException(response.statusCode(), msgPrefix, response.headers(), body);
+  }
+
   /**
    * creates an XmlItem
    * this route creates an XmlItem
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
index a04a5441414..f8076cd6914 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
@@ -67,6 +67,14 @@ public class FakeClassnameTags123Api {
         localVarResponse.body());
   }
 
+  protected ApiException createApiException(HttpResponse<InputStream> response, String msgPrefix) throws IOException {
+    String body = response.body() == null ? null : new String(response.body().readAllBytes());
+    if (body != null) {
+      msgPrefix += ": " + body;
+    }
+    return new ApiException(response.statusCode(), msgPrefix, response.headers(), body);
+  }
+
   /**
    * To test class name in snake case
    * To test class name in snake case
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/PetApi.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/PetApi.java
index 4e9d6f34af7..2dcd304b1f5 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/PetApi.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/PetApi.java
@@ -70,6 +70,14 @@ public class PetApi {
         localVarResponse.body());
   }
 
+  protected ApiException createApiException(HttpResponse<InputStream> response, String msgPrefix) throws IOException {
+    String body = response.body() == null ? null : new String(response.body().readAllBytes());
+    if (body != null) {
+      msgPrefix += ": " + body;
+    }
+    return new ApiException(response.statusCode(), msgPrefix, response.headers(), body);
+  }
+
   /**
    * Add a new pet to the store
    * 
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/StoreApi.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/StoreApi.java
index 41de754a4d9..ec19468ccef 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/StoreApi.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/StoreApi.java
@@ -67,6 +67,14 @@ public class StoreApi {
         localVarResponse.body());
   }
 
+  protected ApiException createApiException(HttpResponse<InputStream> response, String msgPrefix) throws IOException {
+    String body = response.body() == null ? null : new String(response.body().readAllBytes());
+    if (body != null) {
+      msgPrefix += ": " + body;
+    }
+    return new ApiException(response.statusCode(), msgPrefix, response.headers(), body);
+  }
+
   /**
    * Delete purchase order by ID
    * For valid response try integer IDs with value &lt; 1000. Anything above 1000 or nonintegers will generate API errors
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/UserApi.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/UserApi.java
index bb13d02a203..ba2cad99cf8 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/UserApi.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/UserApi.java
@@ -67,6 +67,14 @@ public class UserApi {
         localVarResponse.body());
   }
 
+  protected ApiException createApiException(HttpResponse<InputStream> response, String msgPrefix) throws IOException {
+    String body = response.body() == null ? null : new String(response.body().readAllBytes());
+    if (body != null) {
+      msgPrefix += ": " + body;
+    }
+    return new ApiException(response.statusCode(), msgPrefix, response.headers(), body);
+  }
+
   /**
    * Create user
    * This can only be done by the logged in user.
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 98cdbf0646b..4b5a1fb4bd3 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
@@ -175,7 +175,7 @@ public class ApiClient {
   public ApiClient(HttpClient.Builder builder, ObjectMapper mapper, String baseUri) {
     this.builder = builder;
     this.mapper = mapper;
-    updateBaseUri(baseUri);
+    updateBaseUri(baseUri != null ? baseUri : getDefaultBaseUri());
     interceptor = null;
     readTimeout = null;
     responseInterceptor = null;
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/AnotherFakeApi.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
index 9124c1880fc..2c0088e76d8 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
@@ -58,6 +58,14 @@ public class AnotherFakeApi {
     memberVarResponseInterceptor = apiClient.getResponseInterceptor();
   }
 
+  protected ApiException createApiException(HttpResponse<InputStream> response, String msgPrefix) throws IOException {
+    String body = response.body() == null ? null : new String(response.body().readAllBytes());
+    if (body != null) {
+      msgPrefix += ": " + body;
+    }
+    return new ApiException(response.statusCode(), msgPrefix, response.headers(), body);
+  }
+
   /**
    * To test special tags
    * To test special tags and operation ID starting with number
@@ -87,10 +95,7 @@ public class AnotherFakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "call123testSpecialTags call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "call123testSpecialTags call received non-success response");
       }
       return new ApiResponse<Client>(
           localVarResponse.statusCode(),
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeApi.java
index c174f057dbe..6d3b64d8344 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -66,6 +66,14 @@ public class FakeApi {
     memberVarResponseInterceptor = apiClient.getResponseInterceptor();
   }
 
+  protected ApiException createApiException(HttpResponse<InputStream> response, String msgPrefix) throws IOException {
+    String body = response.body() == null ? null : new String(response.body().readAllBytes());
+    if (body != null) {
+      msgPrefix += ": " + body;
+    }
+    return new ApiException(response.statusCode(), msgPrefix, response.headers(), body);
+  }
+
   /**
    * creates an XmlItem
    * this route creates an XmlItem
@@ -93,10 +101,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "createXmlItem call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "createXmlItem call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -170,10 +175,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "fakeOuterBooleanSerialize call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "fakeOuterBooleanSerialize call received non-success response");
       }
       return new ApiResponse<Boolean>(
           localVarResponse.statusCode(),
@@ -243,10 +245,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "fakeOuterCompositeSerialize call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "fakeOuterCompositeSerialize call received non-success response");
       }
       return new ApiResponse<OuterComposite>(
           localVarResponse.statusCode(),
@@ -316,10 +315,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "fakeOuterNumberSerialize call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "fakeOuterNumberSerialize call received non-success response");
       }
       return new ApiResponse<BigDecimal>(
           localVarResponse.statusCode(),
@@ -389,10 +385,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "fakeOuterStringSerialize call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "fakeOuterStringSerialize call received non-success response");
       }
       return new ApiResponse<String>(
           localVarResponse.statusCode(),
@@ -460,10 +453,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "testBodyWithFileSchema call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "testBodyWithFileSchema call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -537,10 +527,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "testBodyWithQueryParams call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "testBodyWithQueryParams call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -627,10 +614,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "testClientModel call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "testClientModel call received non-success response");
       }
       return new ApiResponse<Client>(
           localVarResponse.statusCode(),
@@ -728,10 +712,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "testEndpointParameters call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "testEndpointParameters call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -823,10 +804,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "testEnumParameters call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "testEnumParameters call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -949,10 +927,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "testGroupParameters call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "testGroupParameters call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -1121,10 +1096,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "testInlineAdditionalProperties call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "testInlineAdditionalProperties call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -1198,10 +1170,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "testJsonFormData call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "testJsonFormData call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -1279,10 +1248,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "testQueryParameterCollectionFormat call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "testQueryParameterCollectionFormat call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
index bc13e4b5cb7..b16a097a9c3 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
@@ -58,6 +58,14 @@ public class FakeClassnameTags123Api {
     memberVarResponseInterceptor = apiClient.getResponseInterceptor();
   }
 
+  protected ApiException createApiException(HttpResponse<InputStream> response, String msgPrefix) throws IOException {
+    String body = response.body() == null ? null : new String(response.body().readAllBytes());
+    if (body != null) {
+      msgPrefix += ": " + body;
+    }
+    return new ApiException(response.statusCode(), msgPrefix, response.headers(), body);
+  }
+
   /**
    * To test class name in snake case
    * To test class name in snake case
@@ -87,10 +95,7 @@ public class FakeClassnameTags123Api {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "testClassname call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "testClassname call received non-success response");
       }
       return new ApiResponse<Client>(
           localVarResponse.statusCode(),
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/PetApi.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/PetApi.java
index 78058c16ada..ff744b27275 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/PetApi.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/PetApi.java
@@ -61,6 +61,14 @@ public class PetApi {
     memberVarResponseInterceptor = apiClient.getResponseInterceptor();
   }
 
+  protected ApiException createApiException(HttpResponse<InputStream> response, String msgPrefix) throws IOException {
+    String body = response.body() == null ? null : new String(response.body().readAllBytes());
+    if (body != null) {
+      msgPrefix += ": " + body;
+    }
+    return new ApiException(response.statusCode(), msgPrefix, response.headers(), body);
+  }
+
   /**
    * Add a new pet to the store
    * 
@@ -88,10 +96,7 @@ public class PetApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "addPet call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "addPet call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -165,10 +170,7 @@ public class PetApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "deletePet call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "deletePet call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -240,10 +242,7 @@ public class PetApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "findPetsByStatus call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "findPetsByStatus call received non-success response");
       }
       return new ApiResponse<List<Pet>>(
           localVarResponse.statusCode(),
@@ -324,10 +323,7 @@ public class PetApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "findPetsByTags call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "findPetsByTags call received non-success response");
       }
       return new ApiResponse<Set<Pet>>(
           localVarResponse.statusCode(),
@@ -404,10 +400,7 @@ public class PetApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "getPetById call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "getPetById call received non-success response");
       }
       return new ApiResponse<Pet>(
           localVarResponse.statusCode(),
@@ -474,10 +467,7 @@ public class PetApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "updatePet call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "updatePet call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -553,10 +543,7 @@ public class PetApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "updatePetWithForm call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "updatePetWithForm call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -629,10 +616,7 @@ public class PetApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "uploadFile call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "uploadFile call received non-success response");
       }
       return new ApiResponse<ModelApiResponse>(
           localVarResponse.statusCode(),
@@ -705,10 +689,7 @@ public class PetApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "uploadFileWithRequiredFile call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "uploadFileWithRequiredFile call received non-success response");
       }
       return new ApiResponse<ModelApiResponse>(
           localVarResponse.statusCode(),
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/StoreApi.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/StoreApi.java
index 845c1567b0c..caffb9cd6ff 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/StoreApi.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/StoreApi.java
@@ -58,6 +58,14 @@ public class StoreApi {
     memberVarResponseInterceptor = apiClient.getResponseInterceptor();
   }
 
+  protected ApiException createApiException(HttpResponse<InputStream> response, String msgPrefix) throws IOException {
+    String body = response.body() == null ? null : new String(response.body().readAllBytes());
+    if (body != null) {
+      msgPrefix += ": " + body;
+    }
+    return new ApiException(response.statusCode(), msgPrefix, response.headers(), body);
+  }
+
   /**
    * Delete purchase order by ID
    * For valid response try integer IDs with value &lt; 1000. Anything above 1000 or nonintegers will generate API errors
@@ -85,10 +93,7 @@ public class StoreApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "deleteOrder call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "deleteOrder call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -155,10 +160,7 @@ public class StoreApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "getInventory call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "getInventory call received non-success response");
       }
       return new ApiResponse<Map<String, Integer>>(
           localVarResponse.statusCode(),
@@ -222,10 +224,7 @@ public class StoreApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "getOrderById call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "getOrderById call received non-success response");
       }
       return new ApiResponse<Order>(
           localVarResponse.statusCode(),
@@ -294,10 +293,7 @@ public class StoreApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "placeOrder call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "placeOrder call received non-success response");
       }
       return new ApiResponse<Order>(
           localVarResponse.statusCode(),
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/UserApi.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/UserApi.java
index 6e5b6a14709..e841c2cd1e6 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/UserApi.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/UserApi.java
@@ -58,6 +58,14 @@ public class UserApi {
     memberVarResponseInterceptor = apiClient.getResponseInterceptor();
   }
 
+  protected ApiException createApiException(HttpResponse<InputStream> response, String msgPrefix) throws IOException {
+    String body = response.body() == null ? null : new String(response.body().readAllBytes());
+    if (body != null) {
+      msgPrefix += ": " + body;
+    }
+    return new ApiException(response.statusCode(), msgPrefix, response.headers(), body);
+  }
+
   /**
    * Create user
    * This can only be done by the logged in user.
@@ -85,10 +93,7 @@ public class UserApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "createUser call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "createUser call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -160,10 +165,7 @@ public class UserApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "createUsersWithArrayInput call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "createUsersWithArrayInput call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -235,10 +237,7 @@ public class UserApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "createUsersWithListInput call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "createUsersWithListInput call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -310,10 +309,7 @@ public class UserApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "deleteUser call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "deleteUser call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -382,10 +378,7 @@ public class UserApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "getUserByName call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "getUserByName call received non-success response");
       }
       return new ApiResponse<User>(
           localVarResponse.statusCode(),
@@ -456,10 +449,7 @@ public class UserApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "loginUser call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "loginUser call received non-success response");
       }
       return new ApiResponse<String>(
           localVarResponse.statusCode(),
@@ -537,10 +527,7 @@ public class UserApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "logoutUser call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "logoutUser call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -604,10 +591,7 @@ public class UserApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "updateUser call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "updateUser call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
diff --git a/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/ApiClient.java b/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/ApiClient.java
index 98cdbf0646b..4b5a1fb4bd3 100644
--- a/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/ApiClient.java
@@ -175,7 +175,7 @@ public class ApiClient {
   public ApiClient(HttpClient.Builder builder, ObjectMapper mapper, String baseUri) {
     this.builder = builder;
     this.mapper = mapper;
-    updateBaseUri(baseUri);
+    updateBaseUri(baseUri != null ? baseUri : getDefaultBaseUri());
     interceptor = null;
     readTimeout = null;
     responseInterceptor = null;
diff --git a/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/AnotherFakeApi.java b/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
index 388e0b3f452..1d87022e718 100644
--- a/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
+++ b/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
@@ -58,6 +58,14 @@ public class AnotherFakeApi {
     memberVarResponseInterceptor = apiClient.getResponseInterceptor();
   }
 
+  protected ApiException createApiException(HttpResponse<InputStream> response, String msgPrefix) throws IOException {
+    String body = response.body() == null ? null : new String(response.body().readAllBytes());
+    if (body != null) {
+      msgPrefix += ": " + body;
+    }
+    return new ApiException(response.statusCode(), msgPrefix, response.headers(), body);
+  }
+
   /**
    * To test special tags
    * To test special tags and operation ID starting with number
@@ -87,10 +95,7 @@ public class AnotherFakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "call123testSpecialTags call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "call123testSpecialTags call received non-success response");
       }
       return new ApiResponse<Client>(
           localVarResponse.statusCode(),
diff --git a/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/DefaultApi.java b/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/DefaultApi.java
index efd1d4ca939..fc06f1fc039 100644
--- a/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/DefaultApi.java
+++ b/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/DefaultApi.java
@@ -58,6 +58,14 @@ public class DefaultApi {
     memberVarResponseInterceptor = apiClient.getResponseInterceptor();
   }
 
+  protected ApiException createApiException(HttpResponse<InputStream> response, String msgPrefix) throws IOException {
+    String body = response.body() == null ? null : new String(response.body().readAllBytes());
+    if (body != null) {
+      msgPrefix += ": " + body;
+    }
+    return new ApiException(response.statusCode(), msgPrefix, response.headers(), body);
+  }
+
   /**
    * 
    * 
@@ -85,10 +93,7 @@ public class DefaultApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "fooGet call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "fooGet call received non-success response");
       }
       return new ApiResponse<InlineResponseDefault>(
           localVarResponse.statusCode(),
diff --git a/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeApi.java
index 402c28afcd2..b5b0a141d33 100644
--- a/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -67,6 +67,14 @@ public class FakeApi {
     memberVarResponseInterceptor = apiClient.getResponseInterceptor();
   }
 
+  protected ApiException createApiException(HttpResponse<InputStream> response, String msgPrefix) throws IOException {
+    String body = response.body() == null ? null : new String(response.body().readAllBytes());
+    if (body != null) {
+      msgPrefix += ": " + body;
+    }
+    return new ApiException(response.statusCode(), msgPrefix, response.headers(), body);
+  }
+
   /**
    * Health check endpoint
    * 
@@ -94,10 +102,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "fakeHealthGet call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "fakeHealthGet call received non-success response");
       }
       return new ApiResponse<HealthCheckResult>(
           localVarResponse.statusCode(),
@@ -161,10 +166,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "fakeOuterBooleanSerialize call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "fakeOuterBooleanSerialize call received non-success response");
       }
       return new ApiResponse<Boolean>(
           localVarResponse.statusCode(),
@@ -234,10 +236,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "fakeOuterCompositeSerialize call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "fakeOuterCompositeSerialize call received non-success response");
       }
       return new ApiResponse<OuterComposite>(
           localVarResponse.statusCode(),
@@ -307,10 +306,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "fakeOuterNumberSerialize call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "fakeOuterNumberSerialize call received non-success response");
       }
       return new ApiResponse<BigDecimal>(
           localVarResponse.statusCode(),
@@ -380,10 +376,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "fakeOuterStringSerialize call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "fakeOuterStringSerialize call received non-success response");
       }
       return new ApiResponse<String>(
           localVarResponse.statusCode(),
@@ -451,10 +444,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "getArrayOfEnums call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "getArrayOfEnums call received non-success response");
       }
       return new ApiResponse<List<OuterEnum>>(
           localVarResponse.statusCode(),
@@ -516,10 +506,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "testBodyWithFileSchema call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "testBodyWithFileSchema call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -593,10 +580,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "testBodyWithQueryParams call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "testBodyWithQueryParams call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -683,10 +667,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "testClientModel call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "testClientModel call received non-success response");
       }
       return new ApiResponse<Client>(
           localVarResponse.statusCode(),
@@ -784,10 +765,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "testEndpointParameters call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "testEndpointParameters call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -879,10 +857,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "testEnumParameters call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "testEnumParameters call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -1005,10 +980,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "testGroupParameters call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "testGroupParameters call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -1177,10 +1149,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "testInlineAdditionalProperties call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "testInlineAdditionalProperties call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -1254,10 +1223,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "testJsonFormData call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "testJsonFormData call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -1335,10 +1301,7 @@ public class FakeApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "testQueryParameterCollectionFormat call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "testQueryParameterCollectionFormat call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
diff --git a/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java b/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
index 8200797995f..caeaf872f78 100644
--- a/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
+++ b/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
@@ -58,6 +58,14 @@ public class FakeClassnameTags123Api {
     memberVarResponseInterceptor = apiClient.getResponseInterceptor();
   }
 
+  protected ApiException createApiException(HttpResponse<InputStream> response, String msgPrefix) throws IOException {
+    String body = response.body() == null ? null : new String(response.body().readAllBytes());
+    if (body != null) {
+      msgPrefix += ": " + body;
+    }
+    return new ApiException(response.statusCode(), msgPrefix, response.headers(), body);
+  }
+
   /**
    * To test class name in snake case
    * To test class name in snake case
@@ -87,10 +95,7 @@ public class FakeClassnameTags123Api {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "testClassname call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "testClassname call received non-success response");
       }
       return new ApiResponse<Client>(
           localVarResponse.statusCode(),
diff --git a/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/PetApi.java b/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/PetApi.java
index d97fb68b908..530d75960d9 100644
--- a/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/PetApi.java
+++ b/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/PetApi.java
@@ -60,6 +60,14 @@ public class PetApi {
     memberVarResponseInterceptor = apiClient.getResponseInterceptor();
   }
 
+  protected ApiException createApiException(HttpResponse<InputStream> response, String msgPrefix) throws IOException {
+    String body = response.body() == null ? null : new String(response.body().readAllBytes());
+    if (body != null) {
+      msgPrefix += ": " + body;
+    }
+    return new ApiException(response.statusCode(), msgPrefix, response.headers(), body);
+  }
+
   /**
    * Add a new pet to the store
    * 
@@ -87,10 +95,7 @@ public class PetApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "addPet call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "addPet call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -164,10 +169,7 @@ public class PetApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "deletePet call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "deletePet call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -239,10 +241,7 @@ public class PetApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "findPetsByStatus call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "findPetsByStatus call received non-success response");
       }
       return new ApiResponse<List<Pet>>(
           localVarResponse.statusCode(),
@@ -323,10 +322,7 @@ public class PetApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "findPetsByTags call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "findPetsByTags call received non-success response");
       }
       return new ApiResponse<List<Pet>>(
           localVarResponse.statusCode(),
@@ -403,10 +399,7 @@ public class PetApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "getPetById call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "getPetById call received non-success response");
       }
       return new ApiResponse<Pet>(
           localVarResponse.statusCode(),
@@ -473,10 +466,7 @@ public class PetApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "updatePet call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "updatePet call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -552,10 +542,7 @@ public class PetApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "updatePetWithForm call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "updatePetWithForm call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -628,10 +615,7 @@ public class PetApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "uploadFile call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "uploadFile call received non-success response");
       }
       return new ApiResponse<ModelApiResponse>(
           localVarResponse.statusCode(),
@@ -704,10 +688,7 @@ public class PetApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "uploadFileWithRequiredFile call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "uploadFileWithRequiredFile call received non-success response");
       }
       return new ApiResponse<ModelApiResponse>(
           localVarResponse.statusCode(),
diff --git a/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/StoreApi.java b/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/StoreApi.java
index 0a4ad790269..c06efabb4a8 100644
--- a/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/StoreApi.java
+++ b/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/StoreApi.java
@@ -58,6 +58,14 @@ public class StoreApi {
     memberVarResponseInterceptor = apiClient.getResponseInterceptor();
   }
 
+  protected ApiException createApiException(HttpResponse<InputStream> response, String msgPrefix) throws IOException {
+    String body = response.body() == null ? null : new String(response.body().readAllBytes());
+    if (body != null) {
+      msgPrefix += ": " + body;
+    }
+    return new ApiException(response.statusCode(), msgPrefix, response.headers(), body);
+  }
+
   /**
    * Delete purchase order by ID
    * For valid response try integer IDs with value &lt; 1000. Anything above 1000 or nonintegers will generate API errors
@@ -85,10 +93,7 @@ public class StoreApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "deleteOrder call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "deleteOrder call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -155,10 +160,7 @@ public class StoreApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "getInventory call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "getInventory call received non-success response");
       }
       return new ApiResponse<Map<String, Integer>>(
           localVarResponse.statusCode(),
@@ -222,10 +224,7 @@ public class StoreApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "getOrderById call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "getOrderById call received non-success response");
       }
       return new ApiResponse<Order>(
           localVarResponse.statusCode(),
@@ -294,10 +293,7 @@ public class StoreApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "placeOrder call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "placeOrder call received non-success response");
       }
       return new ApiResponse<Order>(
           localVarResponse.statusCode(),
diff --git a/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/UserApi.java b/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/UserApi.java
index 56579ab17f0..3c1a68c9881 100644
--- a/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/UserApi.java
+++ b/samples/openapi3/client/petstore/java/native/src/main/java/org/openapitools/client/api/UserApi.java
@@ -58,6 +58,14 @@ public class UserApi {
     memberVarResponseInterceptor = apiClient.getResponseInterceptor();
   }
 
+  protected ApiException createApiException(HttpResponse<InputStream> response, String msgPrefix) throws IOException {
+    String body = response.body() == null ? null : new String(response.body().readAllBytes());
+    if (body != null) {
+      msgPrefix += ": " + body;
+    }
+    return new ApiException(response.statusCode(), msgPrefix, response.headers(), body);
+  }
+
   /**
    * Create user
    * This can only be done by the logged in user.
@@ -85,10 +93,7 @@ public class UserApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "createUser call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "createUser call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -160,10 +165,7 @@ public class UserApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "createUsersWithArrayInput call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "createUsersWithArrayInput call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -235,10 +237,7 @@ public class UserApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "createUsersWithListInput call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "createUsersWithListInput call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -310,10 +309,7 @@ public class UserApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "deleteUser call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "deleteUser call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -382,10 +378,7 @@ public class UserApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "getUserByName call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "getUserByName call received non-success response");
       }
       return new ApiResponse<User>(
           localVarResponse.statusCode(),
@@ -456,10 +449,7 @@ public class UserApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "loginUser call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "loginUser call received non-success response");
       }
       return new ApiResponse<String>(
           localVarResponse.statusCode(),
@@ -537,10 +527,7 @@ public class UserApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "logoutUser call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "logoutUser call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),
@@ -604,10 +591,7 @@ public class UserApi {
         memberVarResponseInterceptor.accept(localVarResponse);
       }
       if (localVarResponse.statusCode()/ 100 != 2) {
-        throw new ApiException(localVarResponse.statusCode(),
-            "updateUser call received non-success response",
-            localVarResponse.headers(),
-            localVarResponse.body() == null ? null : new String(localVarResponse.body().readAllBytes()));
+        throw createApiException(localVarResponse, "updateUser call received non-success response");
       }
       return new ApiResponse<Void>(
           localVarResponse.statusCode(),