diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/restclient/ApiClient.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/restclient/ApiClient.mustache
index 8af468cfb4cf..43d97e14f196 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/restclient/ApiClient.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/restclient/ApiClient.mustache
@@ -87,29 +87,26 @@ public class ApiClient{{#jsr310}} extends JavaTimeFormatter{{/jsr310}} {
 
 
     public ApiClient() {
-        this.dateFormat = createDefaultDateFormat();
-        this.objectMapper = createDefaultObjectMapper(this.dateFormat);
-        this.restClient = buildRestClient(this.objectMapper);
-        this.init();
+        this(null);
     }
 
     public ApiClient(RestClient restClient) {
-        this(Optional.ofNullable(restClient).orElseGet(ApiClient::buildRestClient), createDefaultDateFormat());
+        this(restClient, createDefaultDateFormat());
     }
 
     public ApiClient(ObjectMapper mapper, DateFormat format) {
-        this(buildRestClient(mapper.copy()), format);
+        this(null, mapper, format);
     }
 
     public ApiClient(RestClient restClient, ObjectMapper mapper, DateFormat format) {
-        this(Optional.ofNullable(restClient).orElseGet(() -> buildRestClient(mapper.copy())), format);
+        this.objectMapper = mapper.copy();
+        this.restClient = Optional.ofNullable(restClient).orElseGet(() -> buildRestClient(this.objectMapper));
+        this.dateFormat = format;
+        this.init();
     }
 
     private ApiClient(RestClient restClient, DateFormat format) {
-        this.restClient = restClient;
-        this.dateFormat = format;
-        this.objectMapper = createDefaultObjectMapper(format);
-        this.init();
+        this(restClient, createDefaultObjectMapper(format), format);
     }
 
     public static DateFormat createDefaultDateFormat() {
diff --git a/samples/client/echo_api/java/restclient/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/echo_api/java/restclient/src/main/java/org/openapitools/client/ApiClient.java
index cadf8f35e864..2da8eb124cbf 100644
--- a/samples/client/echo_api/java/restclient/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/echo_api/java/restclient/src/main/java/org/openapitools/client/ApiClient.java
@@ -84,29 +84,26 @@ private String collectionToString(Collection<?> collection) {
 
 
     public ApiClient() {
-        this.dateFormat = createDefaultDateFormat();
-        this.objectMapper = createDefaultObjectMapper(this.dateFormat);
-        this.restClient = buildRestClient(this.objectMapper);
-        this.init();
+        this(null);
     }
 
     public ApiClient(RestClient restClient) {
-        this(Optional.ofNullable(restClient).orElseGet(ApiClient::buildRestClient), createDefaultDateFormat());
+        this(restClient, createDefaultDateFormat());
     }
 
     public ApiClient(ObjectMapper mapper, DateFormat format) {
-        this(buildRestClient(mapper.copy()), format);
+        this(null, mapper, format);
     }
 
     public ApiClient(RestClient restClient, ObjectMapper mapper, DateFormat format) {
-        this(Optional.ofNullable(restClient).orElseGet(() -> buildRestClient(mapper.copy())), format);
+        this.objectMapper = mapper.copy();
+        this.restClient = Optional.ofNullable(restClient).orElseGet(() -> buildRestClient(this.objectMapper));
+        this.dateFormat = format;
+        this.init();
     }
 
     private ApiClient(RestClient restClient, DateFormat format) {
-        this.restClient = restClient;
-        this.dateFormat = format;
-        this.objectMapper = createDefaultObjectMapper(format);
-        this.init();
+        this(restClient, createDefaultObjectMapper(format), format);
     }
 
     public static DateFormat createDefaultDateFormat() {
diff --git a/samples/client/others/java/restclient-useAbstractionForFiles/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/others/java/restclient-useAbstractionForFiles/src/main/java/org/openapitools/client/ApiClient.java
index 490ab1033dfa..3a562ba80e3c 100644
--- a/samples/client/others/java/restclient-useAbstractionForFiles/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/others/java/restclient-useAbstractionForFiles/src/main/java/org/openapitools/client/ApiClient.java
@@ -84,29 +84,26 @@ private String collectionToString(Collection<?> collection) {
 
 
     public ApiClient() {
-        this.dateFormat = createDefaultDateFormat();
-        this.objectMapper = createDefaultObjectMapper(this.dateFormat);
-        this.restClient = buildRestClient(this.objectMapper);
-        this.init();
+        this(null);
     }
 
     public ApiClient(RestClient restClient) {
-        this(Optional.ofNullable(restClient).orElseGet(ApiClient::buildRestClient), createDefaultDateFormat());
+        this(restClient, createDefaultDateFormat());
     }
 
     public ApiClient(ObjectMapper mapper, DateFormat format) {
-        this(buildRestClient(mapper.copy()), format);
+        this(null, mapper, format);
     }
 
     public ApiClient(RestClient restClient, ObjectMapper mapper, DateFormat format) {
-        this(Optional.ofNullable(restClient).orElseGet(() -> buildRestClient(mapper.copy())), format);
+        this.objectMapper = mapper.copy();
+        this.restClient = Optional.ofNullable(restClient).orElseGet(() -> buildRestClient(this.objectMapper));
+        this.dateFormat = format;
+        this.init();
     }
 
     private ApiClient(RestClient restClient, DateFormat format) {
-        this.restClient = restClient;
-        this.dateFormat = format;
-        this.objectMapper = createDefaultObjectMapper(format);
-        this.init();
+        this(restClient, createDefaultObjectMapper(format), format);
     }
 
     public static DateFormat createDefaultDateFormat() {
diff --git a/samples/client/others/typescript/builds/enum-single-value/index.ts b/samples/client/others/typescript/builds/enum-single-value/index.ts
index 791121d1c8dc..c5bc5ff26cc0 100644
--- a/samples/client/others/typescript/builds/enum-single-value/index.ts
+++ b/samples/client/others/typescript/builds/enum-single-value/index.ts
@@ -2,11 +2,11 @@ export * from "./http/http";
 export * from "./auth/auth";
 export * from "./models/all";
 export { createConfiguration } from "./configuration"
-export { Configuration } from "./configuration"
+export type { Configuration } from "./configuration"
 export * from "./apis/exception";
 export * from "./servers";
 export { RequiredError } from "./apis/baseapi";
 
-export { PromiseMiddleware as Middleware } from './middleware';
+export type { PromiseMiddleware as Middleware } from './middleware';
 export { } from './types/PromiseAPI';
 
diff --git a/samples/client/petstore/java/restclient-nullable-arrays/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/restclient-nullable-arrays/src/main/java/org/openapitools/client/ApiClient.java
index c42a51c9a78e..65ce5d69a8d3 100644
--- a/samples/client/petstore/java/restclient-nullable-arrays/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/restclient-nullable-arrays/src/main/java/org/openapitools/client/ApiClient.java
@@ -84,29 +84,26 @@ private String collectionToString(Collection<?> collection) {
 
 
     public ApiClient() {
-        this.dateFormat = createDefaultDateFormat();
-        this.objectMapper = createDefaultObjectMapper(this.dateFormat);
-        this.restClient = buildRestClient(this.objectMapper);
-        this.init();
+        this(null);
     }
 
     public ApiClient(RestClient restClient) {
-        this(Optional.ofNullable(restClient).orElseGet(ApiClient::buildRestClient), createDefaultDateFormat());
+        this(restClient, createDefaultDateFormat());
     }
 
     public ApiClient(ObjectMapper mapper, DateFormat format) {
-        this(buildRestClient(mapper.copy()), format);
+        this(null, mapper, format);
     }
 
     public ApiClient(RestClient restClient, ObjectMapper mapper, DateFormat format) {
-        this(Optional.ofNullable(restClient).orElseGet(() -> buildRestClient(mapper.copy())), format);
+        this.objectMapper = mapper.copy();
+        this.restClient = Optional.ofNullable(restClient).orElseGet(() -> buildRestClient(this.objectMapper));
+        this.dateFormat = format;
+        this.init();
     }
 
     private ApiClient(RestClient restClient, DateFormat format) {
-        this.restClient = restClient;
-        this.dateFormat = format;
-        this.objectMapper = createDefaultObjectMapper(format);
-        this.init();
+        this(restClient, createDefaultObjectMapper(format), format);
     }
 
     public static DateFormat createDefaultDateFormat() {
diff --git a/samples/client/petstore/java/restclient-swagger2/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/restclient-swagger2/src/main/java/org/openapitools/client/ApiClient.java
index 51ae07b26f24..491296f3f9e0 100644
--- a/samples/client/petstore/java/restclient-swagger2/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/restclient-swagger2/src/main/java/org/openapitools/client/ApiClient.java
@@ -85,29 +85,26 @@ private String collectionToString(Collection<?> collection) {
 
 
     public ApiClient() {
-        this.dateFormat = createDefaultDateFormat();
-        this.objectMapper = createDefaultObjectMapper(this.dateFormat);
-        this.restClient = buildRestClient(this.objectMapper);
-        this.init();
+        this(null);
     }
 
     public ApiClient(RestClient restClient) {
-        this(Optional.ofNullable(restClient).orElseGet(ApiClient::buildRestClient), createDefaultDateFormat());
+        this(restClient, createDefaultDateFormat());
     }
 
     public ApiClient(ObjectMapper mapper, DateFormat format) {
-        this(buildRestClient(mapper.copy()), format);
+        this(null, mapper, format);
     }
 
     public ApiClient(RestClient restClient, ObjectMapper mapper, DateFormat format) {
-        this(Optional.ofNullable(restClient).orElseGet(() -> buildRestClient(mapper.copy())), format);
+        this.objectMapper = mapper.copy();
+        this.restClient = Optional.ofNullable(restClient).orElseGet(() -> buildRestClient(this.objectMapper));
+        this.dateFormat = format;
+        this.init();
     }
 
     private ApiClient(RestClient restClient, DateFormat format) {
-        this.restClient = restClient;
-        this.dateFormat = format;
-        this.objectMapper = createDefaultObjectMapper(format);
-        this.init();
+        this(restClient, createDefaultObjectMapper(format), format);
     }
 
     public static DateFormat createDefaultDateFormat() {
diff --git a/samples/client/petstore/java/restclient-useSingleRequestParameter/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/restclient-useSingleRequestParameter/src/main/java/org/openapitools/client/ApiClient.java
index 51ae07b26f24..491296f3f9e0 100644
--- a/samples/client/petstore/java/restclient-useSingleRequestParameter/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/restclient-useSingleRequestParameter/src/main/java/org/openapitools/client/ApiClient.java
@@ -85,29 +85,26 @@ private String collectionToString(Collection<?> collection) {
 
 
     public ApiClient() {
-        this.dateFormat = createDefaultDateFormat();
-        this.objectMapper = createDefaultObjectMapper(this.dateFormat);
-        this.restClient = buildRestClient(this.objectMapper);
-        this.init();
+        this(null);
     }
 
     public ApiClient(RestClient restClient) {
-        this(Optional.ofNullable(restClient).orElseGet(ApiClient::buildRestClient), createDefaultDateFormat());
+        this(restClient, createDefaultDateFormat());
     }
 
     public ApiClient(ObjectMapper mapper, DateFormat format) {
-        this(buildRestClient(mapper.copy()), format);
+        this(null, mapper, format);
     }
 
     public ApiClient(RestClient restClient, ObjectMapper mapper, DateFormat format) {
-        this(Optional.ofNullable(restClient).orElseGet(() -> buildRestClient(mapper.copy())), format);
+        this.objectMapper = mapper.copy();
+        this.restClient = Optional.ofNullable(restClient).orElseGet(() -> buildRestClient(this.objectMapper));
+        this.dateFormat = format;
+        this.init();
     }
 
     private ApiClient(RestClient restClient, DateFormat format) {
-        this.restClient = restClient;
-        this.dateFormat = format;
-        this.objectMapper = createDefaultObjectMapper(format);
-        this.init();
+        this(restClient, createDefaultObjectMapper(format), format);
     }
 
     public static DateFormat createDefaultDateFormat() {
diff --git a/samples/client/petstore/java/restclient/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/restclient/src/main/java/org/openapitools/client/ApiClient.java
index 51ae07b26f24..491296f3f9e0 100644
--- a/samples/client/petstore/java/restclient/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/restclient/src/main/java/org/openapitools/client/ApiClient.java
@@ -85,29 +85,26 @@ private String collectionToString(Collection<?> collection) {
 
 
     public ApiClient() {
-        this.dateFormat = createDefaultDateFormat();
-        this.objectMapper = createDefaultObjectMapper(this.dateFormat);
-        this.restClient = buildRestClient(this.objectMapper);
-        this.init();
+        this(null);
     }
 
     public ApiClient(RestClient restClient) {
-        this(Optional.ofNullable(restClient).orElseGet(ApiClient::buildRestClient), createDefaultDateFormat());
+        this(restClient, createDefaultDateFormat());
     }
 
     public ApiClient(ObjectMapper mapper, DateFormat format) {
-        this(buildRestClient(mapper.copy()), format);
+        this(null, mapper, format);
     }
 
     public ApiClient(RestClient restClient, ObjectMapper mapper, DateFormat format) {
-        this(Optional.ofNullable(restClient).orElseGet(() -> buildRestClient(mapper.copy())), format);
+        this.objectMapper = mapper.copy();
+        this.restClient = Optional.ofNullable(restClient).orElseGet(() -> buildRestClient(this.objectMapper));
+        this.dateFormat = format;
+        this.init();
     }
 
     private ApiClient(RestClient restClient, DateFormat format) {
-        this.restClient = restClient;
-        this.dateFormat = format;
-        this.objectMapper = createDefaultObjectMapper(format);
-        this.init();
+        this(restClient, createDefaultObjectMapper(format), format);
     }
 
     public static DateFormat createDefaultDateFormat() {