Improve Apache Httpclient support (#10624)

* Move apache-httpclient templates to proper dir * Add template for Gradle * Fix few JavaDoc compile warnings * Add properly generated samples * Empty just trigger PR checks rebuild
2025-12-03 08:46:55 +00:00 · 2021-10-23 08:57:32 +02:00
parent 27459b5003
commit 2875c7e14d
17 changed files with 1100 additions and 293 deletions
--- a/samples/client/petstore/java/apache-httpclient/README.md
+++ b/samples/client/petstore/java/apache-httpclient/README.md
@@ -50,14 +50,7 @@ Add this dependency to your project's POM:
 Add this dependency to your project's build file:

 ```groovy
-  repositories {
-    mavenCentral()     // Needed if the 'petstore-apache-httpclient' jar has been published to maven central.
-    mavenLocal()       // Needed if the 'petstore-apache-httpclient' jar has been published to the local maven repo.
-  }
-
-  dependencies {
-     implementation "org.openapitools:petstore-apache-httpclient:1.0.0"
-  }
+compile "org.openapitools:petstore-apache-httpclient:1.0.0"
 ```

 ### Others
--- a/samples/client/petstore/java/apache-httpclient/build.gradle
+++ b/samples/client/petstore/java/apache-httpclient/build.gradle
@@ -119,7 +119,7 @@ ext {
    jackson_databind_nullable_version = "0.2.1"
    jakarta_annotation_version = "1.3.5"
    jackson_threetenbp_version = "2.9.10"
-    jersey_version = "1.19.4"
+    httpclient_version = "4.5.13"
    jodatime_version = "2.9.9"
    junit_version = "4.13.1"
 }
@@ -127,8 +127,8 @@ ext {
 dependencies {
    implementation "io.swagger:swagger-annotations:$swagger_annotations_version"
    implementation "com.google.code.findbugs:jsr305:3.0.2"
-    implementation "com.sun.jersey:jersey-client:$jersey_version"
-    implementation "com.sun.jersey.contribs:jersey-multipart:$jersey_version"
+    implementation "org.apache.httpcomponents:httpclient:$httpclient_version"
+    implementation "org.apache.httpcomponents:httpmime:$httpclient_version"
    implementation "com.fasterxml.jackson.core:jackson-core:$jackson_version"
    implementation "com.fasterxml.jackson.core:jackson-annotations:$jackson_version"
    implementation "com.fasterxml.jackson.core:jackson-databind:$jackson_databind_version"
--- a/samples/client/petstore/java/apache-httpclient/pom.xml
+++ b/samples/client/petstore/java/apache-httpclient/pom.xml
@@ -228,16 +228,16 @@
        </dependency>


-        <!-- HTTP client: jersey-client -->
+        <!-- HTTP client: apache client -->
        <dependency>
-            <groupId>com.sun.jersey</groupId>
-            <artifactId>jersey-client</artifactId>
-            <version>${jersey-version}</version>
+            <groupId>org.apache.httpcomponents</groupId>
+            <artifactId>httpclient</artifactId>
+            <version>${httpclient-version}</version>
        </dependency>
        <dependency>
-            <groupId>com.sun.jersey.contribs</groupId>
-            <artifactId>jersey-multipart</artifactId>
-            <version>${jersey-version}</version>
+            <groupId>org.apache.httpcomponents</groupId>
+            <artifactId>httpmime</artifactId>
+            <version>${httpclient-version}</version>
        </dependency>

        <!-- JSON processing: jackson -->
@@ -288,7 +288,7 @@
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <swagger-annotations-version>1.5.21</swagger-annotations-version>
-        <jersey-version>1.19.4</jersey-version>
+        <httpclient-version>4.5.13</httpclient-version>
        <jackson-version>2.12.1</jackson-version>
        <jackson-threetenbp-version>2.9.10</jackson-threetenbp-version>
        <jakarta-annotation-version>1.3.5</jakarta-annotation-version>
--- a/samples/client/petstore/java/apache-httpclient/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/apache-httpclient/src/main/java/org/openapitools/client/ApiClient.java
@@ -19,21 +19,33 @@ import com.fasterxml.jackson.databind.*;
 import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
 import com.fasterxml.jackson.datatype.threetenbp.ThreeTenModule;
 import com.fasterxml.jackson.jaxrs.json.JacksonJsonProvider;
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.JavaType;

-import com.sun.jersey.api.client.Client;
-import com.sun.jersey.api.client.ClientResponse;
-import com.sun.jersey.api.client.GenericType;
-import com.sun.jersey.api.client.config.DefaultClientConfig;
-import com.sun.jersey.api.client.filter.GZIPContentEncodingFilter;
-import com.sun.jersey.api.client.filter.LoggingFilter;
-import com.sun.jersey.api.client.WebResource.Builder;
-
-import com.sun.jersey.multipart.FormDataMultiPart;
-import com.sun.jersey.multipart.file.FileDataBodyPart;
-
-import javax.ws.rs.core.Cookie;
-import javax.ws.rs.core.Response.Status.Family;
-import javax.ws.rs.core.MediaType;
+import org.apache.http.Header;
+import org.apache.http.HttpEntity;
+import org.apache.http.HttpResponse;
+import org.apache.http.HttpStatus;
+import org.apache.http.NameValuePair;
+import org.apache.http.ParseException;
+import org.apache.http.client.config.RequestConfig;
+import org.apache.http.client.entity.UrlEncodedFormEntity;
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.RequestBuilder;
+import org.apache.http.client.protocol.HttpClientContext;
+import org.apache.http.entity.ByteArrayEntity;
+import org.apache.http.entity.ContentType;
+import org.apache.http.entity.FileEntity;
+import org.apache.http.entity.StringEntity;
+import org.apache.http.entity.mime.MultipartEntityBuilder;
+import org.apache.http.impl.client.BasicCookieStore;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.impl.client.HttpClients;
+import org.apache.http.impl.cookie.BasicClientCookie;
+import org.apache.http.message.BasicNameValuePair;
+import org.apache.http.util.EntityUtils;
+import org.apache.http.cookie.Cookie;

 import java.util.Collection;
 import java.util.Collections;
@@ -46,11 +58,20 @@ import java.util.Arrays;
 import java.util.ArrayList;
 import java.util.Date;
 import java.util.TimeZone;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;

 import java.net.URLEncoder;

 import java.io.File;
+import java.io.InputStream;
+import java.io.IOException;
 import java.io.UnsupportedEncodingException;
+import java.nio.file.Files;
+import java.nio.file.StandardCopyOption;
+import java.nio.file.Paths;
+import java.lang.reflect.Type;
+import java.net.URI;

 import java.text.DateFormat;

@@ -76,8 +97,9 @@ public class ApiClient extends JavaTimeFormatter {
  private boolean debugging = false;
  private int connectionTimeout = 0;

-  private Client httpClient;
+  private CloseableHttpClient httpClient;
  private ObjectMapper objectMapper;
+  protected String tempFolderPath = null;

  private Map<String, Authentication> authentications;

@@ -86,7 +108,10 @@ public class ApiClient extends JavaTimeFormatter {

  private DateFormat dateFormat;

-  public ApiClient() {
+  // Methods that can have a request body
+  private static List<String> bodyMethods = Arrays.asList("POST", "PUT", "DELETE", "PATCH");
+
+  public ApiClient(CloseableHttpClient httpClient) {
    objectMapper = new ObjectMapper();
    objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
    objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
@@ -116,33 +141,17 @@ public class ApiClient extends JavaTimeFormatter {
    // Prevent the authentications from being modified.
    authentications = Collections.unmodifiableMap(authentications);

-    rebuildHttpClient();
+    this.httpClient = httpClient;
+  }
+
+  public ApiClient() {
+    this(HttpClients.createDefault());
  }

  public static DateFormat buildDefaultDateFormat() {
    return new RFC3339DateFormat();
  }

-  /**
-   * Build the Client used to make HTTP requests with the latest settings,
-   * i.e. objectMapper and debugging.
-   * TODO: better to use the Builder Pattern?
-   * @return API client
-   */
-  public ApiClient rebuildHttpClient() {
-    // Add the JSON serialization support to Jersey
-    JacksonJsonProvider jsonProvider = new JacksonJsonProvider(objectMapper);
-    DefaultClientConfig conf = new DefaultClientConfig();
-    conf.getSingletons().add(jsonProvider);
-    Client client = Client.create(conf);
-    client.addFilter(new GZIPContentEncodingFilter(false));
-    if (debugging) {
-      client.addFilter(new LoggingFilter());
-    }
-    this.httpClient = client;
-    return this;
-  }
-
  /**
   * Returns the current object mapper used for JSON serialization/deserialization.
   * <p>
@@ -155,18 +164,22 @@ public class ApiClient extends JavaTimeFormatter {
    return objectMapper;
  }

+  /**
+   * @return API client
+   */
  public ApiClient setObjectMapper(ObjectMapper objectMapper) {
    this.objectMapper = objectMapper;
-    // Need to rebuild the Client as it depends on object mapper.
-    rebuildHttpClient();
    return this;
  }

-  public Client getHttpClient() {
+  public CloseableHttpClient getHttpClient() {
    return httpClient;
  }

-  public ApiClient setHttpClient(Client httpClient) {
+  /**
+   * @return API client
+   */
+  public ApiClient setHttpClient(CloseableHttpClient httpClient) {
    this.httpClient = httpClient;
    return this;
  }
@@ -175,6 +188,9 @@ public class ApiClient extends JavaTimeFormatter {
    return basePath;
  }

+  /**
+   * @return API client
+   */
  public ApiClient setBasePath(String basePath) {
    this.basePath = basePath;
    return this;
@@ -184,6 +200,9 @@ public class ApiClient extends JavaTimeFormatter {
    return servers;
  }

+  /**
+   * @return API client
+   */
  public ApiClient setServers(List<ServerConfiguration> servers) {
    this.servers = servers;
    return this;
@@ -193,6 +212,9 @@ public class ApiClient extends JavaTimeFormatter {
    return serverIndex;
  }

+  /**
+   * @return API client
+   */
  public ApiClient setServerIndex(Integer serverIndex) {
    this.serverIndex = serverIndex;
    return this;
@@ -202,6 +224,9 @@ public class ApiClient extends JavaTimeFormatter {
    return serverVariables;
  }

+  /**
+   * @return API client
+   */
  public ApiClient setServerVariables(Map<String, String> serverVariables) {
    this.serverVariables = serverVariables;
    return this;
@@ -241,16 +266,28 @@ public class ApiClient extends JavaTimeFormatter {
    return authentications.get(authName);
  }

+  /**
+   * The path of temporary folder used to store downloaded files from endpoints
+   * with file response. The default value is <code>null</code>, i.e. using
+   * the system's default temporary folder.
+   *
+   * @return Temp folder path
+   */
+  public String getTempFolderPath() {
+    return tempFolderPath;
+  }
+

  /**
   * Helper method to set username for the first HTTP basic authentication.
   * @param username Username
+   * @return API client
   */
-  public void setUsername(String username) {
+  public ApiClient setUsername(String username) {
    for (Authentication auth : authentications.values()) {
      if (auth instanceof HttpBasicAuth) {
        ((HttpBasicAuth) auth).setUsername(username);
-        return;
+        return this;
      }
    }
    throw new RuntimeException("No HTTP basic authentication configured!");
@@ -259,12 +296,13 @@ public class ApiClient extends JavaTimeFormatter {
  /**
   * Helper method to set password for the first HTTP basic authentication.
   * @param password Password
+   * @return API client
   */
-  public void setPassword(String password) {
+  public ApiClient setPassword(String password) {
    for (Authentication auth : authentications.values()) {
      if (auth instanceof HttpBasicAuth) {
        ((HttpBasicAuth) auth).setPassword(password);
-        return;
+        return this;
      }
    }
    throw new RuntimeException("No HTTP basic authentication configured!");
@@ -274,12 +312,13 @@ public class ApiClient extends JavaTimeFormatter {
  /**
   * Helper method to set API key value for the first API key authentication.
   * @param apiKey the API key
+   * @return API client
   */
-  public void setApiKey(String apiKey) {
+  public ApiClient setApiKey(String apiKey) {
    for (Authentication auth : authentications.values()) {
      if (auth instanceof ApiKeyAuth) {
        ((ApiKeyAuth) auth).setApiKey(apiKey);
-        return;
+        return this;
      }
    }
    throw new RuntimeException("No API key authentication configured!");
@@ -288,12 +327,13 @@ public class ApiClient extends JavaTimeFormatter {
  /**
   * Helper method to set API key prefix for the first API key authentication.
   * @param apiKeyPrefix API key prefix
+   * @return API client
   */
-  public void setApiKeyPrefix(String apiKeyPrefix) {
+  public ApiClient setApiKeyPrefix(String apiKeyPrefix) {
    for (Authentication auth : authentications.values()) {
      if (auth instanceof ApiKeyAuth) {
        ((ApiKeyAuth) auth).setApiKeyPrefix(apiKeyPrefix);
-        return;
+        return this;
      }
    }
    throw new RuntimeException("No API key authentication configured!");
@@ -303,12 +343,13 @@ public class ApiClient extends JavaTimeFormatter {
  /**
   * Helper method to set access token for the first OAuth2 authentication.
   * @param accessToken Access token
+   * @return API client
   */
-  public void setAccessToken(String accessToken) {
+  public ApiClient setAccessToken(String accessToken) {
    for (Authentication auth : authentications.values()) {
      if (auth instanceof OAuth) {
        ((OAuth) auth).setAccessToken(accessToken);
-        return;
+        return this;
      }
    }
    throw new RuntimeException("No OAuth2 authentication configured!");
@@ -325,6 +366,16 @@ public class ApiClient extends JavaTimeFormatter {
    return this;
  }

+  /**
+   * Set temp folder path
+   * @param tempFolderPath Temp folder path
+   * @return API client
+   */
+  public ApiClient setTempFolderPath(String tempFolderPath) {
+    this.tempFolderPath = tempFolderPath;
+    return this;
+  }
+
  /**
   * Add a default header.
   *
@@ -364,9 +415,8 @@ public class ApiClient extends JavaTimeFormatter {
   * @return API client
   */
  public ApiClient setDebugging(boolean debugging) {
+    // TODO: implement debugging mode
    this.debugging = debugging;
-    // Need to rebuild the Client as it depends on the value of debugging.
-    rebuildHttpClient();
    return this;
  }

@@ -387,7 +437,6 @@ public class ApiClient extends JavaTimeFormatter {
   */
   public ApiClient setConnectTimeout(int connectionTimeout) {
     this.connectionTimeout = connectionTimeout;
-     httpClient.setConnectTimeout(connectionTimeout);
     return this;
   }

@@ -408,8 +457,6 @@ public class ApiClient extends JavaTimeFormatter {
    this.dateFormat = dateFormat;
    // Also set the date format for model (de)serialization with Date properties.
    this.objectMapper.setDateFormat((DateFormat) dateFormat.clone());
-    // Need to rebuild the Client as objectMapper changes.
-    rebuildHttpClient();
    return this;
  }

@@ -600,6 +647,46 @@ public class ApiClient extends JavaTimeFormatter {
    }
  }

+  /**
+   * Transform response headers into map
+   */
+  protected Map<String, List<String>> transformResponseHeaders(Header[] headers) {
+    Map<String, List<String>> headersMap = new HashMap<>();
+    for (Header header : headers) {
+      List<String> valuesList = headersMap.get(header.getName());
+      if (valuesList != null) {
+        valuesList.add(header.getValue());
+      } else {
+        valuesList = new ArrayList<>();
+        valuesList.add(header.getValue());
+        headersMap.put(header.getName(), valuesList);
+      }
+    }
+    return headersMap;
+  }
+
+  /**
+   * Parse content type object from header value
+   */
+  private ContentType getContentType(String headerValue) throws ApiException {
+    try {
+      return ContentType.parse(headerValue);
+    } catch (ParseException e) {
+      throw new ApiException("Could not parse content type " + headerValue);
+    }
+  }
+
+  /**
+   * Get content type of a response or null if one was not provided
+   */
+  private String getResponseMimeType(HttpResponse response) throws ApiException {
+    Header contentTypeHeader = response.getFirstHeader("Content-Type");
+    if (contentTypeHeader != null) {
+      return getContentType(contentTypeHeader.getValue()).getMimeType();
+    }
+    return null;
+  }
+
  /**
   * Serialize the given Java object into string according the given
   * Content-Type (only JSON is supported for now).
@@ -609,33 +696,118 @@ public class ApiClient extends JavaTimeFormatter {
   * @return Object
   * @throws ApiException API exception
   */
-  public Object serialize(Object obj, String contentType, Map<String, Object> formParams) throws ApiException {
-    if (contentType.startsWith("multipart/form-data")) {
-      FormDataMultiPart mp = new FormDataMultiPart();
-      for (Entry<String, Object> param: formParams.entrySet()) {
-        if( param.getValue() instanceof List && !( ( List ) param.getValue() ).isEmpty()
-                  && ( ( List ) param.getValue() ).get( 0 ) instanceof File ) {
-            @SuppressWarnings( "unchecked" )
-            List<File> files = ( List<File> ) param.getValue();
-            for( File file : files ) {
-              mp.bodyPart( new FileDataBodyPart( param.getKey(), file, MediaType.APPLICATION_OCTET_STREAM_TYPE ) );
-            }
-        } else if (param.getValue() instanceof File) {
-          File file = (File) param.getValue();
-          mp.bodyPart(new FileDataBodyPart(param.getKey(), file, MediaType.APPLICATION_OCTET_STREAM_TYPE));
+  public HttpEntity serialize(Object obj, Map<String, Object> formParams, ContentType contentType) throws ApiException {
+    String mimeType = contentType.getMimeType();
+    if (isJsonMime(mimeType)) {
+      try {
+        return new StringEntity(objectMapper.writeValueAsString(obj), contentType);
+      } catch (JsonProcessingException e) {
+        throw new ApiException(e);
+      }
+    } else if (mimeType.equals(ContentType.MULTIPART_FORM_DATA.getMimeType())) {
+      MultipartEntityBuilder multiPartBuilder = MultipartEntityBuilder.create();
+      for (Entry<String, Object> paramEntry : formParams.entrySet()) {
+        Object value = paramEntry.getValue();
+        if (value instanceof File) {
+          multiPartBuilder.addBinaryBody(paramEntry.getKey(), (File) value);
+        } else if (value instanceof byte[]) {
+          multiPartBuilder.addBinaryBody(paramEntry.getKey(), (byte[]) value);
        } else {
-          mp.field(param.getKey(), parameterToString(param.getValue()), MediaType.MULTIPART_FORM_DATA_TYPE);
+          multiPartBuilder.addTextBody(paramEntry.getKey(), parameterToString(paramEntry.getValue()));
        }
      }
-      return mp;
-    } else if (contentType.startsWith("application/x-www-form-urlencoded")) {
-      return this.getXWWWFormUrlencodedParams(formParams);
+      return multiPartBuilder.build();
+    } else if (mimeType.equals(ContentType.APPLICATION_FORM_URLENCODED.getMimeType())) {
+      List<NameValuePair> formValues = new ArrayList<>();
+      for (Entry<String, Object> paramEntry : formParams.entrySet()) {
+        formValues.add(new BasicNameValuePair(paramEntry.getKey(), parameterToString(paramEntry.getValue())));
+      }
+      try {
+        return new UrlEncodedFormEntity(formValues);
+      } catch (UnsupportedEncodingException e) {
+        throw new ApiException(e);
+      }
    } else {
-      // We let Jersey attempt to serialize the body
-      return obj;
+      // Handle files with unknown content type
+      if (obj instanceof File) {
+        return new FileEntity((File) obj, contentType);
+      } else if (obj instanceof byte[]) {
+        return new ByteArrayEntity((byte[]) obj, contentType);
+      }
+      throw new ApiException("Serialization for content type '" + contentType + "' not supported");
    }
  }

+  /**
+   * Deserialize response content
+   */
+  public <T> T deserialize(HttpResponse response, TypeReference<T> valueType) throws ApiException, IOException {
+    if (valueType == null) {
+      return null;
+    }
+    HttpEntity entity = response.getEntity();
+    Type valueRawType = valueType.getType();
+    if (valueRawType.equals(byte[].class)) {
+      return (T) EntityUtils.toByteArray(entity);
+    } else if (valueRawType.equals(File.class)) {
+      return (T) downloadFileFromResponse(response);
+    }
+    String mimeType = getResponseMimeType(response);
+    if (mimeType == null || isJsonMime(mimeType)) {
+      // Assume json if no mime type
+      return objectMapper.readValue(entity.getContent(), valueType);
+    } else {
+      throw new ApiException(
+          "Deserialization for content type '" + mimeType + "' not supported for type '" + valueType + "'",
+          response.getStatusLine().getStatusCode(),
+          responseHeaders,
+          EntityUtils.toString(entity)
+      );
+    }
+  }
+
+  private File downloadFileFromResponse(HttpResponse response) throws IOException {
+    Header contentDispositionHeader = response.getFirstHeader("Content-Disposition");
+    String contentDisposition = contentDispositionHeader == null ? null : contentDispositionHeader.getValue();
+    File file = prepareDownloadFile(contentDisposition);
+    Files.copy(response.getEntity().getContent(), file.toPath(), StandardCopyOption.REPLACE_EXISTING);
+    return file;
+  }
+
+  protected File prepareDownloadFile(String contentDisposition) throws IOException {
+    String filename = null;
+    if (contentDisposition != null && !"".equals(contentDisposition)) {
+      // Get filename from the Content-Disposition header.
+      Pattern pattern = Pattern.compile("filename=['\"]?([^'\"\\s]+)['\"]?");
+      Matcher matcher = pattern.matcher(contentDisposition);
+      if (matcher.find())
+        filename = matcher.group(1);
+    }
+
+    String prefix;
+    String suffix = null;
+    if (filename == null) {
+      prefix = "download-";
+      suffix = "";
+    } else {
+      int pos = filename.lastIndexOf('.');
+      if (pos == -1) {
+        prefix = filename + "-";
+      } else {
+        prefix = filename.substring(0, pos) + "-";
+        suffix = filename.substring(pos);
+      }
+      // Files.createTempFile requires the prefix to be at least three characters long
+      if (prefix.length() < 3)
+        prefix = "download-";
+    }
+
+    if (tempFolderPath == null)
+      return Files.createTempFile(prefix, suffix).toFile();
+    else
+      return Files.createTempFile(Paths.get(tempFolderPath), prefix, suffix).toFile();
+  }
+
  /**
   * Build full URL by concatenating base path, the given sub path and query parameters.
   *
@@ -697,57 +869,34 @@ public class ApiClient extends JavaTimeFormatter {
    return url.toString();
  }

-  private ClientResponse getAPIResponse(String path, String method, List<Pair> queryParams, List<Pair> collectionQueryParams, Object body, Map<String, String> headerParams, Map<String, String> cookieParams, Map<String, Object> formParams, String accept, String contentType, String[] authNames) throws ApiException {
-    if (body != null && !formParams.isEmpty()) {
-      throw new ApiException(500, "Cannot have body and form params");
+  protected boolean isSuccessfulStatus(int statusCode) {
+    return statusCode >= 200 && statusCode < 300;
+  }
+
+  protected boolean isBodyAllowed(String method) {
+    return bodyMethods.contains(method);
+  }
+
+  protected Cookie buildCookie(String key, String value, URI uri) {
+    BasicClientCookie cookie = new BasicClientCookie(key, value);
+    cookie.setDomain(uri.getHost());
+    cookie.setPath("/");
+    return cookie;
+  }
+
+  protected <T> T processResponse(CloseableHttpResponse response, TypeReference<T> returnType) throws ApiException, IOException {
+    statusCode = response.getStatusLine().getStatusCode();
+    if (statusCode == HttpStatus.SC_NO_CONTENT) {
+      return null;
    }

-    updateParamsForAuth(authNames, queryParams, headerParams, cookieParams);
-
-    final String url = buildUrl(path, queryParams, collectionQueryParams);
-    Builder builder;
-    if (accept == null) {
-      builder = httpClient.resource(url).getRequestBuilder();
+    responseHeaders = transformResponseHeaders(response.getAllHeaders());
+    if (isSuccessfulStatus(statusCode)) {
+      return this.deserialize(response, returnType);
    } else {
-      builder = httpClient.resource(url).accept(accept);
+      String message = EntityUtils.toString(response.getEntity());
+      throw new ApiException(message, statusCode, responseHeaders, message);
    }
-
-    for (Entry<String, String> keyValue : headerParams.entrySet()) {
-      builder = builder.header(keyValue.getKey(), keyValue.getValue());
-    }
-    for (Map.Entry<String,String> keyValue : defaultHeaderMap.entrySet()) {
-      if (!headerParams.containsKey(keyValue.getKey())) {
-        builder = builder.header(keyValue.getKey(), keyValue.getValue());
-      }
-    }
-
-    for (Entry<String, String> keyValue : cookieParams.entrySet()) {
-      builder = builder.cookie(new Cookie(keyValue.getKey(), keyValue.getValue()));
-    }
-    for (Map.Entry<String,String> keyValue : defaultCookieMap.entrySet()) {
-      if (!cookieParams.containsKey(keyValue.getKey())) {
-        builder = builder.cookie(new Cookie(keyValue.getKey(), keyValue.getValue()));
-      }
-    }
-
-    ClientResponse response = null;
-
-    if ("GET".equals(method)) {
-      response = (ClientResponse) builder.get(ClientResponse.class);
-    } else if ("POST".equals(method)) {
-      response = builder.type(contentType).post(ClientResponse.class, serialize(body, contentType, formParams));
-    } else if ("PUT".equals(method)) {
-      response = builder.type(contentType).put(ClientResponse.class, serialize(body, contentType, formParams));
-    } else if ("DELETE".equals(method)) {
-      response = builder.type(contentType).delete(ClientResponse.class, serialize(body, contentType, formParams));
-    } else if ("PATCH".equals(method)) {
-      response = builder.type(contentType).header("X-HTTP-Method-Override", "PATCH").post(ClientResponse.class, serialize(body, contentType, formParams));
-    } else if ("HEAD".equals(method)) {
-      response = builder.head();
-    } else {
-      throw new ApiException(500, "unknown method type " + method);
-    }
-    return response;
  }

  /**
@@ -769,36 +918,73 @@ public class ApiClient extends JavaTimeFormatter {
   * @return The response body in type of string
   * @throws ApiException API exception
   */
-   public <T> T invokeAPI(String path, String method, List<Pair> queryParams, List<Pair> collectionQueryParams, Object body, Map<String, String> headerParams, Map<String, String> cookieParams, Map<String, Object> formParams, String accept, String contentType, String[] authNames, GenericType<T> returnType) throws ApiException {
+   public <T> T invokeAPI(
+       String path,
+       String method,
+       List<Pair> queryParams,
+       List<Pair> collectionQueryParams,
+       Object body,
+       Map<String, String> headerParams,
+       Map<String, String> cookieParams,
+       Map<String, Object> formParams,
+       String accept,
+       String contentType,
+       String[] authNames,
+       TypeReference<T> returnType) throws ApiException {
+    if (body != null && !formParams.isEmpty()) {
+      throw new ApiException("Cannot have body and form params");
+    }

-    ClientResponse response = getAPIResponse(path, method, queryParams, collectionQueryParams, body, headerParams, cookieParams, formParams, accept, contentType, authNames);
+    updateParamsForAuth(authNames, queryParams, headerParams, cookieParams);
+    final String url = buildUrl(path, queryParams, collectionQueryParams);

-    statusCode = response.getStatusInfo().getStatusCode();
-    responseHeaders = response.getHeaders();
+    RequestBuilder builder = RequestBuilder.create(method);
+    builder.setUri(url);

-    if(response.getStatusInfo().getStatusCode() == ClientResponse.Status.NO_CONTENT.getStatusCode()) {
-      return null;
-    } else if (response.getStatusInfo().getFamily() == Family.SUCCESSFUL) {
-      if (returnType == null)
-        return null;
-      else
-        return response.getEntity(returnType);
-    } else {
-      String message = "error";
-      String respBody = null;
-      if (response.hasEntity()) {
-        try {
-          respBody = response.getEntity(String.class);
-          message = respBody;
-        } catch (RuntimeException e) {
-          // e.printStackTrace();
-        }
+    RequestConfig config = RequestConfig.custom()
+      .setConnectionRequestTimeout(connectionTimeout)
+      .build();
+    builder.setConfig(config);
+
+    if (accept != null) {
+      builder.addHeader("Accept", accept);
+    }
+    for (Entry<String, String> keyValue : headerParams.entrySet()) {
+      builder.addHeader(keyValue.getKey(), keyValue.getValue());
+    }
+    for (Map.Entry<String,String> keyValue : defaultHeaderMap.entrySet()) {
+      if (!headerParams.containsKey(keyValue.getKey())) {
+        builder.addHeader(keyValue.getKey(), keyValue.getValue());
      }
-      throw new ApiException(
-        response.getStatusInfo().getStatusCode(),
-        message,
-        response.getHeaders(),
-        respBody);
+    }
+
+    BasicCookieStore store = new BasicCookieStore();
+    for (Entry<String, String> keyValue : cookieParams.entrySet()) {
+      store.addCookie(buildCookie(keyValue.getKey(), keyValue.getValue(), builder.getUri()));
+    }
+    for (Entry<String,String> keyValue : defaultCookieMap.entrySet()) {
+      if (!cookieParams.containsKey(keyValue.getKey())) {
+        store.addCookie(buildCookie(keyValue.getKey(), keyValue.getValue(), builder.getUri()));
+      }
+    }
+
+    HttpClientContext context = HttpClientContext.create();
+    context.setCookieStore(store);
+
+    ContentType contentTypeObj = getContentType(contentType);
+    if (body != null || !formParams.isEmpty()) {
+      if (isBodyAllowed(method)) {
+        // Add entity if we have content and a valid method
+        builder.setEntity(serialize(body, formParams, contentTypeObj));
+      } else {
+        throw new ApiException("method " + method + " does not support a request body");
+      }
+    }
+
+    try (CloseableHttpResponse response = httpClient.execute(builder.build(), context)) {
+      return processResponse(response, returnType);
+    } catch (IOException e) {
+      throw new ApiException(e);
    }
  }

@@ -817,32 +1003,4 @@ public class ApiClient extends JavaTimeFormatter {
      auth.applyToParams(queryParams, headerParams, cookieParams);
    }
  }
-
-  /**
-   * Encode the given form parameters as request body.
-   * @param formParams Form parameters
-   * @return HTTP form encoded parameters
-   */
-  private String getXWWWFormUrlencodedParams(Map<String, Object> formParams) {
-    StringBuilder formParamBuilder = new StringBuilder();
-
-    for (Entry<String, Object> param : formParams.entrySet()) {
-      String valueStr = parameterToString(param.getValue());
-      try {
-        formParamBuilder.append(URLEncoder.encode(param.getKey(), "utf8"))
-            .append("=")
-            .append(URLEncoder.encode(valueStr, "utf8"));
-        formParamBuilder.append("&");
-      } catch (UnsupportedEncodingException e) {
-        // move on to next
-      }
-    }
-
-    String encodedFormParams = formParamBuilder.toString();
-    if (encodedFormParams.endsWith("&")) {
-      encodedFormParams = encodedFormParams.substring(0, encodedFormParams.length() - 1);
-    }
-
-    return encodedFormParams;
-  }
 }
--- a/samples/client/petstore/java/apache-httpclient/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
+++ b/samples/client/petstore/java/apache-httpclient/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
@@ -12,7 +12,7 @@

 package org.openapitools.client.api;

-import com.sun.jersey.api.client.GenericType;
+import com.fasterxml.jackson.core.type.TypeReference;

 import org.openapitools.client.ApiException;
 import org.openapitools.client.ApiClient;
@@ -89,7 +89,20 @@ public class AnotherFakeApi {

    String[] localVarAuthNames = new String[] {  };

-    GenericType<Client> localVarReturnType = new GenericType<Client>() {};
-    return apiClient.invokeAPI(localVarPath, "PATCH", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
-      }
+    TypeReference<Client> localVarReturnType = new TypeReference<Client>() {};
+    return apiClient.invokeAPI(
+        localVarPath,
+        "PATCH",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        localVarReturnType
+    );
+  }
 }
--- a/samples/client/petstore/java/apache-httpclient/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/apache-httpclient/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -12,7 +12,7 @@

 package org.openapitools.client.api;

-import com.sun.jersey.api.client.GenericType;
+import com.fasterxml.jackson.core.type.TypeReference;

 import org.openapitools.client.ApiException;
 import org.openapitools.client.ApiClient;
@@ -96,8 +96,20 @@ public class FakeApi {

    String[] localVarAuthNames = new String[] {  };

-
-    apiClient.invokeAPI(localVarPath, "POST", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, null);
+    apiClient.invokeAPI(
+        localVarPath,
+        "POST",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        null
+    );
  }
  /**
   * 
@@ -135,9 +147,22 @@ public class FakeApi {

    String[] localVarAuthNames = new String[] {  };

-    GenericType<Boolean> localVarReturnType = new GenericType<Boolean>() {};
-    return apiClient.invokeAPI(localVarPath, "POST", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
-      }
+    TypeReference<Boolean> localVarReturnType = new TypeReference<Boolean>() {};
+    return apiClient.invokeAPI(
+        localVarPath,
+        "POST",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        localVarReturnType
+    );
+  }
  /**
   * 
   * Test serialization of object with outer number type
@@ -174,9 +199,22 @@ public class FakeApi {

    String[] localVarAuthNames = new String[] {  };

-    GenericType<OuterComposite> localVarReturnType = new GenericType<OuterComposite>() {};
-    return apiClient.invokeAPI(localVarPath, "POST", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
-      }
+    TypeReference<OuterComposite> localVarReturnType = new TypeReference<OuterComposite>() {};
+    return apiClient.invokeAPI(
+        localVarPath,
+        "POST",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        localVarReturnType
+    );
+  }
  /**
   * 
   * Test serialization of outer number types
@@ -213,9 +251,22 @@ public class FakeApi {

    String[] localVarAuthNames = new String[] {  };

-    GenericType<BigDecimal> localVarReturnType = new GenericType<BigDecimal>() {};
-    return apiClient.invokeAPI(localVarPath, "POST", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
-      }
+    TypeReference<BigDecimal> localVarReturnType = new TypeReference<BigDecimal>() {};
+    return apiClient.invokeAPI(
+        localVarPath,
+        "POST",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        localVarReturnType
+    );
+  }
  /**
   * 
   * Test serialization of outer string types
@@ -252,9 +303,22 @@ public class FakeApi {

    String[] localVarAuthNames = new String[] {  };

-    GenericType<String> localVarReturnType = new GenericType<String>() {};
-    return apiClient.invokeAPI(localVarPath, "POST", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
-      }
+    TypeReference<String> localVarReturnType = new TypeReference<String>() {};
+    return apiClient.invokeAPI(
+        localVarPath,
+        "POST",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        localVarReturnType
+    );
+  }
  /**
   * 
   * For this test, the body for this request much reference a schema named &#x60;File&#x60;.
@@ -295,8 +359,20 @@ public class FakeApi {

    String[] localVarAuthNames = new String[] {  };

-
-    apiClient.invokeAPI(localVarPath, "PUT", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, null);
+    apiClient.invokeAPI(
+        localVarPath,
+        "PUT",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        null
+    );
  }
  /**
   * 
@@ -345,8 +421,20 @@ public class FakeApi {

    String[] localVarAuthNames = new String[] {  };

-
-    apiClient.invokeAPI(localVarPath, "PUT", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, null);
+    apiClient.invokeAPI(
+        localVarPath,
+        "PUT",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        null
+    );
  }
  /**
   * To test \&quot;client\&quot; model
@@ -389,9 +477,22 @@ public class FakeApi {

    String[] localVarAuthNames = new String[] {  };

-    GenericType<Client> localVarReturnType = new GenericType<Client>() {};
-    return apiClient.invokeAPI(localVarPath, "PATCH", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
-      }
+    TypeReference<Client> localVarReturnType = new TypeReference<Client>() {};
+    return apiClient.invokeAPI(
+        localVarPath,
+        "PATCH",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        localVarReturnType
+    );
+  }
  /**
   * Fake endpoint for testing various parameters  假端點  偽のエンドポイント  가짜 엔드 포인트
   * Fake endpoint for testing various parameters  假端點  偽のエンドポイント  가짜 엔드 포인트
@@ -488,8 +589,20 @@ if (paramCallback != null)

    String[] localVarAuthNames = new String[] { "http_basic_test" };

-
-    apiClient.invokeAPI(localVarPath, "POST", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, null);
+    apiClient.invokeAPI(
+        localVarPath,
+        "POST",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        null
+    );
  }
  /**
   * To test enum parameters
@@ -545,8 +658,20 @@ if (enumFormString != null)

    String[] localVarAuthNames = new String[] {  };

-
-    apiClient.invokeAPI(localVarPath, "GET", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, null);
+    apiClient.invokeAPI(
+        localVarPath,
+        "GET",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        null
+    );
  }
  /**
   * Fake endpoint to test group parameters (optional)
@@ -611,8 +736,20 @@ if (booleanGroup != null)

    String[] localVarAuthNames = new String[] {  };

-
-    apiClient.invokeAPI(localVarPath, "DELETE", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, null);
+    apiClient.invokeAPI(
+        localVarPath,
+        "DELETE",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        null
+    );
  }
  /**
   * test inline additionalProperties
@@ -654,8 +791,20 @@ if (booleanGroup != null)

    String[] localVarAuthNames = new String[] {  };

-
-    apiClient.invokeAPI(localVarPath, "POST", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, null);
+    apiClient.invokeAPI(
+        localVarPath,
+        "POST",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        null
+    );
  }
  /**
   * test json serialization of form data
@@ -707,8 +856,20 @@ if (param2 != null)

    String[] localVarAuthNames = new String[] {  };

-
-    apiClient.invokeAPI(localVarPath, "GET", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, null);
+    apiClient.invokeAPI(
+        localVarPath,
+        "GET",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        null
+    );
  }
  /**
   * 
@@ -779,7 +940,19 @@ if (param2 != null)

    String[] localVarAuthNames = new String[] {  };

-
-    apiClient.invokeAPI(localVarPath, "PUT", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, null);
+    apiClient.invokeAPI(
+        localVarPath,
+        "PUT",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        null
+    );
  }
 }
--- a/samples/client/petstore/java/apache-httpclient/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
+++ b/samples/client/petstore/java/apache-httpclient/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
@@ -12,7 +12,7 @@

 package org.openapitools.client.api;

-import com.sun.jersey.api.client.GenericType;
+import com.fasterxml.jackson.core.type.TypeReference;

 import org.openapitools.client.ApiException;
 import org.openapitools.client.ApiClient;
@@ -89,7 +89,20 @@ public class FakeClassnameTags123Api {

    String[] localVarAuthNames = new String[] { "api_key_query" };

-    GenericType<Client> localVarReturnType = new GenericType<Client>() {};
-    return apiClient.invokeAPI(localVarPath, "PATCH", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
-      }
+    TypeReference<Client> localVarReturnType = new TypeReference<Client>() {};
+    return apiClient.invokeAPI(
+        localVarPath,
+        "PATCH",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        localVarReturnType
+    );
+  }
 }
--- a/samples/client/petstore/java/apache-httpclient/src/main/java/org/openapitools/client/api/PetApi.java
+++ b/samples/client/petstore/java/apache-httpclient/src/main/java/org/openapitools/client/api/PetApi.java
@@ -12,7 +12,7 @@

 package org.openapitools.client.api;

-import com.sun.jersey.api.client.GenericType;
+import com.fasterxml.jackson.core.type.TypeReference;

 import org.openapitools.client.ApiException;
 import org.openapitools.client.ApiClient;
@@ -91,8 +91,20 @@ public class PetApi {

    String[] localVarAuthNames = new String[] { "petstore_auth" };

-
-    apiClient.invokeAPI(localVarPath, "POST", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, null);
+    apiClient.invokeAPI(
+        localVarPath,
+        "POST",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        null
+    );
  }
  /**
   * Deletes a pet
@@ -138,8 +150,20 @@ public class PetApi {

    String[] localVarAuthNames = new String[] { "petstore_auth" };

-
-    apiClient.invokeAPI(localVarPath, "DELETE", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, null);
+    apiClient.invokeAPI(
+        localVarPath,
+        "DELETE",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        null
+    );
  }
  /**
   * Finds Pets by status
@@ -183,9 +207,22 @@ public class PetApi {

    String[] localVarAuthNames = new String[] { "petstore_auth" };

-    GenericType<List<Pet>> localVarReturnType = new GenericType<List<Pet>>() {};
-    return apiClient.invokeAPI(localVarPath, "GET", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
-      }
+    TypeReference<List<Pet>> localVarReturnType = new TypeReference<List<Pet>>() {};
+    return apiClient.invokeAPI(
+        localVarPath,
+        "GET",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        localVarReturnType
+    );
+  }
  /**
   * Finds Pets by tags
   * Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
@@ -230,9 +267,22 @@ public class PetApi {

    String[] localVarAuthNames = new String[] { "petstore_auth" };

-    GenericType<Set<Pet>> localVarReturnType = new GenericType<Set<Pet>>() {};
-    return apiClient.invokeAPI(localVarPath, "GET", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
-      }
+    TypeReference<Set<Pet>> localVarReturnType = new TypeReference<Set<Pet>>() {};
+    return apiClient.invokeAPI(
+        localVarPath,
+        "GET",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        localVarReturnType
+    );
+  }
  /**
   * Find pet by ID
   * Returns a single pet
@@ -275,9 +325,22 @@ public class PetApi {

    String[] localVarAuthNames = new String[] { "api_key" };

-    GenericType<Pet> localVarReturnType = new GenericType<Pet>() {};
-    return apiClient.invokeAPI(localVarPath, "GET", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
-      }
+    TypeReference<Pet> localVarReturnType = new TypeReference<Pet>() {};
+    return apiClient.invokeAPI(
+        localVarPath,
+        "GET",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        localVarReturnType
+    );
+  }
  /**
   * Update an existing pet
   * 
@@ -318,8 +381,20 @@ public class PetApi {

    String[] localVarAuthNames = new String[] { "petstore_auth" };

-
-    apiClient.invokeAPI(localVarPath, "PUT", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, null);
+    apiClient.invokeAPI(
+        localVarPath,
+        "PUT",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        null
+    );
  }
  /**
   * Updates a pet in the store with form data
@@ -368,8 +443,20 @@ if (status != null)

    String[] localVarAuthNames = new String[] { "petstore_auth" };

-
-    apiClient.invokeAPI(localVarPath, "POST", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, null);
+    apiClient.invokeAPI(
+        localVarPath,
+        "POST",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        null
+    );
  }
  /**
   * uploads an image
@@ -419,9 +506,22 @@ if (file != null)

    String[] localVarAuthNames = new String[] { "petstore_auth" };

-    GenericType<ModelApiResponse> localVarReturnType = new GenericType<ModelApiResponse>() {};
-    return apiClient.invokeAPI(localVarPath, "POST", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
-      }
+    TypeReference<ModelApiResponse> localVarReturnType = new TypeReference<ModelApiResponse>() {};
+    return apiClient.invokeAPI(
+        localVarPath,
+        "POST",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        localVarReturnType
+    );
+  }
  /**
   * uploads an image (required)
   * 
@@ -475,7 +575,20 @@ if (requiredFile != null)

    String[] localVarAuthNames = new String[] { "petstore_auth" };

-    GenericType<ModelApiResponse> localVarReturnType = new GenericType<ModelApiResponse>() {};
-    return apiClient.invokeAPI(localVarPath, "POST", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
-      }
+    TypeReference<ModelApiResponse> localVarReturnType = new TypeReference<ModelApiResponse>() {};
+    return apiClient.invokeAPI(
+        localVarPath,
+        "POST",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        localVarReturnType
+    );
+  }
 }
--- a/samples/client/petstore/java/apache-httpclient/src/main/java/org/openapitools/client/api/StoreApi.java
+++ b/samples/client/petstore/java/apache-httpclient/src/main/java/org/openapitools/client/api/StoreApi.java
@@ -12,7 +12,7 @@

 package org.openapitools.client.api;

-import com.sun.jersey.api.client.GenericType;
+import com.fasterxml.jackson.core.type.TypeReference;

 import org.openapitools.client.ApiException;
 import org.openapitools.client.ApiClient;
@@ -89,8 +89,20 @@ public class StoreApi {

    String[] localVarAuthNames = new String[] {  };

-
-    apiClient.invokeAPI(localVarPath, "DELETE", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, null);
+    apiClient.invokeAPI(
+        localVarPath,
+        "DELETE",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        null
+    );
  }
  /**
   * Returns pet inventories by status
@@ -127,9 +139,22 @@ public class StoreApi {

    String[] localVarAuthNames = new String[] { "api_key" };

-    GenericType<Map<String, Integer>> localVarReturnType = new GenericType<Map<String, Integer>>() {};
-    return apiClient.invokeAPI(localVarPath, "GET", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
-      }
+    TypeReference<Map<String, Integer>> localVarReturnType = new TypeReference<Map<String, Integer>>() {};
+    return apiClient.invokeAPI(
+        localVarPath,
+        "GET",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        localVarReturnType
+    );
+  }
  /**
   * Find purchase order by ID
   * For valid response try integer IDs with value &lt;&#x3D; 5 or &gt; 10. Other values will generated exceptions
@@ -172,9 +197,22 @@ public class StoreApi {

    String[] localVarAuthNames = new String[] {  };

-    GenericType<Order> localVarReturnType = new GenericType<Order>() {};
-    return apiClient.invokeAPI(localVarPath, "GET", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
-      }
+    TypeReference<Order> localVarReturnType = new TypeReference<Order>() {};
+    return apiClient.invokeAPI(
+        localVarPath,
+        "GET",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        localVarReturnType
+    );
+  }
  /**
   * Place an order for a pet
   * 
@@ -216,7 +254,20 @@ public class StoreApi {

    String[] localVarAuthNames = new String[] {  };

-    GenericType<Order> localVarReturnType = new GenericType<Order>() {};
-    return apiClient.invokeAPI(localVarPath, "POST", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
-      }
+    TypeReference<Order> localVarReturnType = new TypeReference<Order>() {};
+    return apiClient.invokeAPI(
+        localVarPath,
+        "POST",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        localVarReturnType
+    );
+  }
 }
--- a/samples/client/petstore/java/apache-httpclient/src/main/java/org/openapitools/client/api/UserApi.java
+++ b/samples/client/petstore/java/apache-httpclient/src/main/java/org/openapitools/client/api/UserApi.java
@@ -12,7 +12,7 @@

 package org.openapitools.client.api;

-import com.sun.jersey.api.client.GenericType;
+import com.fasterxml.jackson.core.type.TypeReference;

 import org.openapitools.client.ApiException;
 import org.openapitools.client.ApiClient;
@@ -88,8 +88,20 @@ public class UserApi {

    String[] localVarAuthNames = new String[] {  };

-
-    apiClient.invokeAPI(localVarPath, "POST", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, null);
+    apiClient.invokeAPI(
+        localVarPath,
+        "POST",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        null
+    );
  }
  /**
   * Creates list of users with given input array
@@ -131,8 +143,20 @@ public class UserApi {

    String[] localVarAuthNames = new String[] {  };

-
-    apiClient.invokeAPI(localVarPath, "POST", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, null);
+    apiClient.invokeAPI(
+        localVarPath,
+        "POST",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        null
+    );
  }
  /**
   * Creates list of users with given input array
@@ -174,8 +198,20 @@ public class UserApi {

    String[] localVarAuthNames = new String[] {  };

-
-    apiClient.invokeAPI(localVarPath, "POST", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, null);
+    apiClient.invokeAPI(
+        localVarPath,
+        "POST",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        null
+    );
  }
  /**
   * Delete user
@@ -218,8 +254,20 @@ public class UserApi {

    String[] localVarAuthNames = new String[] {  };

-
-    apiClient.invokeAPI(localVarPath, "DELETE", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, null);
+    apiClient.invokeAPI(
+        localVarPath,
+        "DELETE",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        null
+    );
  }
  /**
   * Get user by user name
@@ -263,9 +311,22 @@ public class UserApi {

    String[] localVarAuthNames = new String[] {  };

-    GenericType<User> localVarReturnType = new GenericType<User>() {};
-    return apiClient.invokeAPI(localVarPath, "GET", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
-      }
+    TypeReference<User> localVarReturnType = new TypeReference<User>() {};
+    return apiClient.invokeAPI(
+        localVarPath,
+        "GET",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        localVarReturnType
+    );
+  }
  /**
   * Logs user into the system
   * 
@@ -315,9 +376,22 @@ public class UserApi {

    String[] localVarAuthNames = new String[] {  };

-    GenericType<String> localVarReturnType = new GenericType<String>() {};
-    return apiClient.invokeAPI(localVarPath, "GET", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localVarReturnType);
-      }
+    TypeReference<String> localVarReturnType = new TypeReference<String>() {};
+    return apiClient.invokeAPI(
+        localVarPath,
+        "GET",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        localVarReturnType
+    );
+  }
  /**
   * Logs out current logged in user session
   * 
@@ -352,8 +426,20 @@ public class UserApi {

    String[] localVarAuthNames = new String[] {  };

-
-    apiClient.invokeAPI(localVarPath, "GET", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, null);
+    apiClient.invokeAPI(
+        localVarPath,
+        "GET",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        null
+    );
  }
  /**
   * Updated user
@@ -402,7 +488,19 @@ public class UserApi {

    String[] localVarAuthNames = new String[] {  };

-
-    apiClient.invokeAPI(localVarPath, "PUT", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, null);
+    apiClient.invokeAPI(
+        localVarPath,
+        "PUT",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        null
+    );
  }
 }