diff --git a/modules/swagger-codegen/src/main/resources/android-java/api.mustache b/modules/swagger-codegen/src/main/resources/android-java/api.mustache
index 1eab419d31ad..83a43b428531 100644
--- a/modules/swagger-codegen/src/main/resources/android-java/api.mustache
+++ b/modules/swagger-codegen/src/main/resources/android-java/api.mustache
@@ -10,6 +10,9 @@ import java.util.*;
 {{#imports}}import {{import}};
 {{/imports}}
 
+import org.apache.http.HttpEntity;
+import org.apache.http.entity.mime.MultipartEntityBuilder;
+
 import java.util.Map;
 import java.util.HashMap;
 import java.io.File;
@@ -55,19 +58,46 @@ public class {{classname}} {
 
     // query params
     Map<String, String> queryParams = new HashMap<String, String>();
+    // header params
     Map<String, String> headerParams = new HashMap<String, String>();
+    // form params
+    Map<String, String> formParams = new HashMap<String, String>();
 
-    {{#queryParams}}if(!"null".equals(String.valueOf({{paramName}})))
-      queryParams.put("{{baseName}}", String.valueOf({{paramName}}));
+    {{#queryParams}}if ({{paramName}} != null)
+      queryParams.put("{{baseName}}", ApiInvoker.parameterToString({{paramName}}));
     {{/queryParams}}
 
-    {{#headerParams}}headerParams.put("{{baseName}}", {{paramName}});
+    {{#headerParams}}headerParams.put("{{baseName}}", ApiInvoker.parameterToString({{paramName}}));
     {{/headerParams}}
 
-    String contentType = "application/json";
+    String[] contentTypes = {
+      {{#consumes}}"{{mediaType}}"{{#hasMore}},{{/hasMore}}{{/consumes}}
+    };
+    String contentType = contentTypes.length > 0 ? contentTypes[0] : "application/json";
+
+    if (contentType.startsWith("multipart/form-data")) {
+      // file uploading
+      MultipartEntityBuilder builder = MultipartEntityBuilder.create();
+      {{#formParams}}{{#notFile}}
+      if ({{paramName}} != null) {
+        builder.addTextBody("{{baseName}}", ApiInvoker.parameterToString({{paramName}}), ApiInvoker.TEXT_PLAIN_UTF8);
+      }
+      {{/notFile}}{{#isFile}}
+      if ({{paramName}} != null) {
+        builder.addBinaryBody("{{baseName}}", {{paramName}});
+      }
+      {{/isFile}}{{/formParams}}
+
+      HttpEntity httpEntity = builder.build();
+      postBody = httpEntity;
+    } else {
+      // normal form params
+      {{#formParams}}{{#notFile}}formParams.put("{{baseName}}", ApiInvoker.parameterToString({{paramName}}));{{/notFile}}
+      {{/formParams}}
+    }
 
     try {
-      String response = apiInvoker.invokeAPI(basePath, path, "{{httpMethod}}", queryParams, postBody, headerParams, contentType);
+      String response = apiInvoker.invokeAPI(basePath, path, "{{httpMethod}}", queryParams, postBody, headerParams, formParams, contentType);
       if(response != null){
         return {{#returnType}}({{{returnType}}}) ApiInvoker.deserialize(response, "{{returnContainer}}", {{returnBaseType}}.class){{/returnType}};
       }
diff --git a/modules/swagger-codegen/src/main/resources/android-java/apiInvoker.mustache b/modules/swagger-codegen/src/main/resources/android-java/apiInvoker.mustache
index 425c2e7e004c..8b31abd48abe 100644
--- a/modules/swagger-codegen/src/main/resources/android-java/apiInvoker.mustache
+++ b/modules/swagger-codegen/src/main/resources/android-java/apiInvoker.mustache
@@ -12,6 +12,7 @@ import org.apache.http.client.methods.*;
 import org.apache.http.conn.*;
 import org.apache.http.conn.scheme.*;
 import org.apache.http.conn.ssl.*;
+import org.apache.http.entity.ContentType;
 import org.apache.http.entity.StringEntity;
 import org.apache.http.impl.client.*;
 import org.apache.http.impl.conn.*;
@@ -40,6 +41,7 @@ import java.text.DateFormat;
 import java.text.SimpleDateFormat;
 
 import java.util.Date;
+import java.util.TimeZone;
 import java.util.Random;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -61,6 +63,61 @@ public class ApiInvoker {
 
   private ClientConnectionManager ignoreSSLConnectionManager;
 
+  /** Content type "text/plain" with UTF-8 encoding. */
+  public static final ContentType TEXT_PLAIN_UTF8 = ContentType.create("text/plain", Consts.UTF_8);
+
+  /**
+   * ISO 8601 date time format.
+   * @see https://en.wikipedia.org/wiki/ISO_8601
+   */
+  public static final SimpleDateFormat DATE_TIME_FORMAT = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssXXX");
+
+  /**
+   * ISO 8601 date format.
+   * @see https://en.wikipedia.org/wiki/ISO_8601
+   */
+  public static final SimpleDateFormat DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd");
+
+  static {
+    // Use UTC as the default time zone.
+    DATE_TIME_FORMAT.setTimeZone(TimeZone.getTimeZone("UTC"));
+    DATE_FORMAT.setTimeZone(TimeZone.getTimeZone("UTC"));
+  }
+
+  public static Date parseDateTime(String str) {
+    try {
+      return DATE_TIME_FORMAT.parse(str);
+    } catch (java.text.ParseException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  public static Date parseDate(String str) {
+    try {
+      return DATE_FORMAT.parse(str);
+    } catch (java.text.ParseException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  public static String formatDateTime(Date datetime) {
+    return DATE_TIME_FORMAT.format(datetime);
+  }
+
+  public static String formatDate(Date date) {
+    return DATE_FORMAT.format(date);
+  }
+
+  public static String parameterToString(Object param) {
+    if (param == null) {
+      return "";
+    } else if (param instanceof Date) {
+      return formatDateTime((Date) param);
+    } else {
+      return String.valueOf(param);
+    }
+  }
+
   public ApiInvoker() {
     initConnectionManager();
   }
@@ -91,7 +148,7 @@ public class ApiInvoker {
       else if(String.class.equals(cls)) {
         if(json != null && json.startsWith("\"") && json.endsWith("\"") && json.length() > 1)
           return json.substring(1, json.length() - 2);
-        else 
+        else
           return json;
       }
       else {
@@ -105,9 +162,9 @@ public class ApiInvoker {
 
   public static String serialize(Object obj) throws ApiException {
     try {
-      if (obj != null) 
+      if (obj != null)
         return JsonUtil.getJsonMapper().writeValueAsString(obj);
-      else 
+      else
         return null;
     }
     catch (Exception e) {
@@ -115,7 +172,7 @@ public class ApiInvoker {
     }
   }
 
-  public String invokeAPI(String host, String path, String method, Map<String, String> queryParams, Object body, Map<String, String> headerParams, String contentType) throws ApiException {
+  public String invokeAPI(String host, String path, String method, Map<String, String> queryParams, Object body, Map<String, String> headerParams, Map<String, String> formParams, String contentType) throws ApiException {
     HttpClient client = getClient(host);
 
     StringBuilder b = new StringBuilder();
@@ -136,7 +193,7 @@ public class ApiInvoker {
     for(String key : headerParams.keySet()) {
       headers.put(key, headerParams.get(key));
     }
-    
+
     for(String key : defaultHeaderMap.keySet()) {
       if(!headerParams.containsKey(key)) {
         headers.put(key, defaultHeaderMap.get(key));
@@ -144,9 +201,34 @@ public class ApiInvoker {
     }
     headers.put("Accept", "application/json");
 
+    // URL encoded string from form parameters
+    String formParamStr = null;
+
+    // for form data
+    if ("application/x-www-form-urlencoded".equals(contentType)) {
+      StringBuilder formParamBuilder = new StringBuilder();
+
+      // encode the form params
+      for (String key : formParams.keySet()) {
+        String value = formParams.get(key);
+        if (value != null && !"".equals(value.trim())) {
+          if (formParamBuilder.length() > 0) {
+            formParamBuilder.append("&");
+          }
+          try {
+            formParamBuilder.append(URLEncoder.encode(key, "utf8")).append("=").append(URLEncoder.encode(value, "utf8"));
+          }
+          catch (Exception e) {
+            // move on to next
+          }
+        }
+      }
+      formParamStr = formParamBuilder.toString();
+    }
+
     HttpResponse response = null;
-    try{
-      if("GET".equals(method)) {
+    try {
+      if ("GET".equals(method)) {
         HttpGet get = new HttpGet(url);
         get.addHeader("Accept", "application/json");
         for(String key : headers.keySet()) {
@@ -156,10 +238,17 @@ public class ApiInvoker {
       }
       else if ("POST".equals(method)) {
         HttpPost post = new HttpPost(url);
-
-        if (body != null) {
+        if (formParamStr != null) {
           post.setHeader("Content-Type", contentType);
-          post.setEntity(new StringEntity(serialize(body), "UTF-8"));
+          post.setEntity(new StringEntity(formParamStr, "UTF-8"));
+        } else if (body != null) {
+          if (body instanceof HttpEntity) {
+            // this is for file uploading
+            post.setEntity((HttpEntity) body);
+          } else {
+            post.setHeader("Content-Type", contentType);
+            post.setEntity(new StringEntity(serialize(body), "UTF-8"));
+          }
         }
         for(String key : headers.keySet()) {
           post.setHeader(key, headers.get(key));
@@ -168,7 +257,10 @@ public class ApiInvoker {
       }
       else if ("PUT".equals(method)) {
         HttpPut put = new HttpPut(url);
-        if(body != null) {
+        if (formParamStr != null) {
+          put.setHeader("Content-Type", contentType);
+          put.setEntity(new StringEntity(formParamStr, "UTF-8"));
+        } else if (body != null) {
           put.setHeader("Content-Type", contentType);
           put.setEntity(new StringEntity(serialize(body), "UTF-8"));
         }
@@ -186,8 +278,10 @@ public class ApiInvoker {
       }
       else if ("PATCH".equals(method)) {
         HttpPatch patch = new HttpPatch(url);
-
-        if (body != null) {
+        if (formParamStr != null) {
+          patch.setHeader("Content-Type", contentType);
+          patch.setEntity(new StringEntity(formParamStr, "UTF-8"));
+        } else if (body != null) {
           patch.setHeader("Content-Type", contentType);
           patch.setEntity(new StringEntity(serialize(body), "UTF-8"));
         }
@@ -199,7 +293,7 @@ public class ApiInvoker {
 
       int code = response.getStatusLine().getStatusCode();
       String responseString = null;
-      if(code == 204) 
+      if(code == 204)
         responseString = "";
       else if(code >= 200 && code < 300) {
         if(response.getEntity() != null) {
diff --git a/modules/swagger-codegen/src/main/resources/android-java/pom.mustache b/modules/swagger-codegen/src/main/resources/android-java/pom.mustache
index 5f48aadfa128..8a01631edb06 100644
--- a/modules/swagger-codegen/src/main/resources/android-java/pom.mustache
+++ b/modules/swagger-codegen/src/main/resources/android-java/pom.mustache
@@ -136,6 +136,12 @@
       <version>${httpclient-version}</version>
       <scope>compile</scope>
     </dependency>
+    <dependency>
+      <groupId>org.apache.httpcomponents</groupId>
+      <artifactId>httpmime</artifactId>
+      <version>${httpclient-version}</version>
+      <scope>compile</scope>
+    </dependency>
 
     <!-- test dependencies -->
     <dependency>
@@ -157,6 +163,6 @@
     <junit-version>4.8.1</junit-version>
     <maven-plugin-version>1.0.0</maven-plugin-version>
     <junit-version>4.8.1</junit-version>
-    <httpclient-version>4.0</httpclient-version>
+    <httpclient-version>4.3.6</httpclient-version>
   </properties>
 </project>
diff --git a/samples/client/petstore/android-java/pom.xml b/samples/client/petstore/android-java/pom.xml
index ef2be59b188b..003a4450b5bb 100644
--- a/samples/client/petstore/android-java/pom.xml
+++ b/samples/client/petstore/android-java/pom.xml
@@ -136,6 +136,12 @@
       <version>${httpclient-version}</version>
       <scope>compile</scope>
     </dependency>
+    <dependency>
+      <groupId>org.apache.httpcomponents</groupId>
+      <artifactId>httpmime</artifactId>
+      <version>${httpclient-version}</version>
+      <scope>compile</scope>
+    </dependency>
 
     <!-- test dependencies -->
     <dependency>
@@ -157,6 +163,6 @@
     <junit-version>4.8.1</junit-version>
     <maven-plugin-version>1.0.0</maven-plugin-version>
     <junit-version>4.8.1</junit-version>
-    <httpclient-version>4.0</httpclient-version>
+    <httpclient-version>4.3.6</httpclient-version>
   </properties>
 </project>
diff --git a/samples/client/petstore/android-java/src/main/java/io/swagger/client/ApiInvoker.java b/samples/client/petstore/android-java/src/main/java/io/swagger/client/ApiInvoker.java
index 6306e0734a96..9eb217fe7369 100644
--- a/samples/client/petstore/android-java/src/main/java/io/swagger/client/ApiInvoker.java
+++ b/samples/client/petstore/android-java/src/main/java/io/swagger/client/ApiInvoker.java
@@ -12,6 +12,7 @@ import org.apache.http.client.methods.*;
 import org.apache.http.conn.*;
 import org.apache.http.conn.scheme.*;
 import org.apache.http.conn.ssl.*;
+import org.apache.http.entity.ContentType;
 import org.apache.http.entity.StringEntity;
 import org.apache.http.impl.client.*;
 import org.apache.http.impl.conn.*;
@@ -40,6 +41,7 @@ import java.text.DateFormat;
 import java.text.SimpleDateFormat;
 
 import java.util.Date;
+import java.util.TimeZone;
 import java.util.Random;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -61,6 +63,61 @@ public class ApiInvoker {
 
   private ClientConnectionManager ignoreSSLConnectionManager;
 
+  /** Content type "text/plain" with UTF-8 encoding. */
+  public static final ContentType TEXT_PLAIN_UTF8 = ContentType.create("text/plain", Consts.UTF_8);
+
+  /**
+   * ISO 8601 date time format.
+   * @see https://en.wikipedia.org/wiki/ISO_8601
+   */
+  public static final SimpleDateFormat DATE_TIME_FORMAT = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssXXX");
+
+  /**
+   * ISO 8601 date format.
+   * @see https://en.wikipedia.org/wiki/ISO_8601
+   */
+  public static final SimpleDateFormat DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd");
+
+  static {
+    // Use UTC as the default time zone.
+    DATE_TIME_FORMAT.setTimeZone(TimeZone.getTimeZone("UTC"));
+    DATE_FORMAT.setTimeZone(TimeZone.getTimeZone("UTC"));
+  }
+
+  public static Date parseDateTime(String str) {
+    try {
+      return DATE_TIME_FORMAT.parse(str);
+    } catch (java.text.ParseException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  public static Date parseDate(String str) {
+    try {
+      return DATE_FORMAT.parse(str);
+    } catch (java.text.ParseException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  public static String formatDateTime(Date datetime) {
+    return DATE_TIME_FORMAT.format(datetime);
+  }
+
+  public static String formatDate(Date date) {
+    return DATE_FORMAT.format(date);
+  }
+
+  public static String parameterToString(Object param) {
+    if (param == null) {
+      return "";
+    } else if (param instanceof Date) {
+      return formatDateTime((Date) param);
+    } else {
+      return String.valueOf(param);
+    }
+  }
+
   public ApiInvoker() {
     initConnectionManager();
   }
@@ -91,7 +148,7 @@ public class ApiInvoker {
       else if(String.class.equals(cls)) {
         if(json != null && json.startsWith("\"") && json.endsWith("\"") && json.length() > 1)
           return json.substring(1, json.length() - 2);
-        else 
+        else
           return json;
       }
       else {
@@ -105,9 +162,9 @@ public class ApiInvoker {
 
   public static String serialize(Object obj) throws ApiException {
     try {
-      if (obj != null) 
+      if (obj != null)
         return JsonUtil.getJsonMapper().writeValueAsString(obj);
-      else 
+      else
         return null;
     }
     catch (Exception e) {
@@ -115,7 +172,7 @@ public class ApiInvoker {
     }
   }
 
-  public String invokeAPI(String host, String path, String method, Map<String, String> queryParams, Object body, Map<String, String> headerParams, String contentType) throws ApiException {
+  public String invokeAPI(String host, String path, String method, Map<String, String> queryParams, Object body, Map<String, String> headerParams, Map<String, String> formParams, String contentType) throws ApiException {
     HttpClient client = getClient(host);
 
     StringBuilder b = new StringBuilder();
@@ -136,7 +193,7 @@ public class ApiInvoker {
     for(String key : headerParams.keySet()) {
       headers.put(key, headerParams.get(key));
     }
-    
+
     for(String key : defaultHeaderMap.keySet()) {
       if(!headerParams.containsKey(key)) {
         headers.put(key, defaultHeaderMap.get(key));
@@ -144,9 +201,34 @@ public class ApiInvoker {
     }
     headers.put("Accept", "application/json");
 
+    // URL encoded string from form parameters
+    String formParamStr = null;
+
+    // for form data
+    if ("application/x-www-form-urlencoded".equals(contentType)) {
+      StringBuilder formParamBuilder = new StringBuilder();
+
+      // encode the form params
+      for (String key : formParams.keySet()) {
+        String value = formParams.get(key);
+        if (value != null && !"".equals(value.trim())) {
+          if (formParamBuilder.length() > 0) {
+            formParamBuilder.append("&");
+          }
+          try {
+            formParamBuilder.append(URLEncoder.encode(key, "utf8")).append("=").append(URLEncoder.encode(value, "utf8"));
+          }
+          catch (Exception e) {
+            // move on to next
+          }
+        }
+      }
+      formParamStr = formParamBuilder.toString();
+    }
+
     HttpResponse response = null;
-    try{
-      if("GET".equals(method)) {
+    try {
+      if ("GET".equals(method)) {
         HttpGet get = new HttpGet(url);
         get.addHeader("Accept", "application/json");
         for(String key : headers.keySet()) {
@@ -156,10 +238,17 @@ public class ApiInvoker {
       }
       else if ("POST".equals(method)) {
         HttpPost post = new HttpPost(url);
-
-        if (body != null) {
+        if (formParamStr != null) {
           post.setHeader("Content-Type", contentType);
-          post.setEntity(new StringEntity(serialize(body), "UTF-8"));
+          post.setEntity(new StringEntity(formParamStr, "UTF-8"));
+        } else if (body != null) {
+          if (body instanceof HttpEntity) {
+            // this is for file uploading
+            post.setEntity((HttpEntity) body);
+          } else {
+            post.setHeader("Content-Type", contentType);
+            post.setEntity(new StringEntity(serialize(body), "UTF-8"));
+          }
         }
         for(String key : headers.keySet()) {
           post.setHeader(key, headers.get(key));
@@ -168,7 +257,10 @@ public class ApiInvoker {
       }
       else if ("PUT".equals(method)) {
         HttpPut put = new HttpPut(url);
-        if(body != null) {
+        if (formParamStr != null) {
+          put.setHeader("Content-Type", contentType);
+          put.setEntity(new StringEntity(formParamStr, "UTF-8"));
+        } else if (body != null) {
           put.setHeader("Content-Type", contentType);
           put.setEntity(new StringEntity(serialize(body), "UTF-8"));
         }
@@ -186,8 +278,10 @@ public class ApiInvoker {
       }
       else if ("PATCH".equals(method)) {
         HttpPatch patch = new HttpPatch(url);
-
-        if (body != null) {
+        if (formParamStr != null) {
+          patch.setHeader("Content-Type", contentType);
+          patch.setEntity(new StringEntity(formParamStr, "UTF-8"));
+        } else if (body != null) {
           patch.setHeader("Content-Type", contentType);
           patch.setEntity(new StringEntity(serialize(body), "UTF-8"));
         }
@@ -199,7 +293,7 @@ public class ApiInvoker {
 
       int code = response.getStatusLine().getStatusCode();
       String responseString = null;
-      if(code == 204) 
+      if(code == 204)
         responseString = "";
       else if(code >= 200 && code < 300) {
         if(response.getEntity() != null) {
diff --git a/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/PetApi.java b/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/PetApi.java
index 7b58b8e5e024..41e10687ce7d 100644
--- a/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/PetApi.java
+++ b/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/PetApi.java
@@ -10,6 +10,9 @@ import java.util.*;
 import io.swagger.client.model.Pet;
 import java.io.File;
 
+import org.apache.http.HttpEntity;
+import org.apache.http.entity.mime.MultipartEntityBuilder;
+
 import java.util.Map;
 import java.util.HashMap;
 import java.io.File;
@@ -46,16 +49,34 @@ public class PetApi {
 
     // query params
     Map<String, String> queryParams = new HashMap<String, String>();
+    // header params
     Map<String, String> headerParams = new HashMap<String, String>();
+    // form params
+    Map<String, String> formParams = new HashMap<String, String>();
 
     
 
     
 
-    String contentType = "application/json";
+    String[] contentTypes = {
+      "application/json","application/xml"
+    };
+    String contentType = contentTypes.length > 0 ? contentTypes[0] : "application/json";
+
+    if (contentType.startsWith("multipart/form-data")) {
+      // file uploading
+      MultipartEntityBuilder builder = MultipartEntityBuilder.create();
+      
+
+      HttpEntity httpEntity = builder.build();
+      postBody = httpEntity;
+    } else {
+      // normal form params
+      
+    }
 
     try {
-      String response = apiInvoker.invokeAPI(basePath, path, "PUT", queryParams, postBody, headerParams, contentType);
+      String response = apiInvoker.invokeAPI(basePath, path, "PUT", queryParams, postBody, headerParams, formParams, contentType);
       if(response != null){
         return ;
       }
@@ -83,16 +104,34 @@ public class PetApi {
 
     // query params
     Map<String, String> queryParams = new HashMap<String, String>();
+    // header params
     Map<String, String> headerParams = new HashMap<String, String>();
+    // form params
+    Map<String, String> formParams = new HashMap<String, String>();
 
     
 
     
 
-    String contentType = "application/json";
+    String[] contentTypes = {
+      "application/json","application/xml"
+    };
+    String contentType = contentTypes.length > 0 ? contentTypes[0] : "application/json";
+
+    if (contentType.startsWith("multipart/form-data")) {
+      // file uploading
+      MultipartEntityBuilder builder = MultipartEntityBuilder.create();
+      
+
+      HttpEntity httpEntity = builder.build();
+      postBody = httpEntity;
+    } else {
+      // normal form params
+      
+    }
 
     try {
-      String response = apiInvoker.invokeAPI(basePath, path, "POST", queryParams, postBody, headerParams, contentType);
+      String response = apiInvoker.invokeAPI(basePath, path, "POST", queryParams, postBody, headerParams, formParams, contentType);
       if(response != null){
         return ;
       }
@@ -120,18 +159,36 @@ public class PetApi {
 
     // query params
     Map<String, String> queryParams = new HashMap<String, String>();
+    // header params
     Map<String, String> headerParams = new HashMap<String, String>();
+    // form params
+    Map<String, String> formParams = new HashMap<String, String>();
 
-    if(!"null".equals(String.valueOf(status)))
-      queryParams.put("status", String.valueOf(status));
+    if (status != null)
+      queryParams.put("status", ApiInvoker.parameterToString(status));
     
 
     
 
-    String contentType = "application/json";
+    String[] contentTypes = {
+      
+    };
+    String contentType = contentTypes.length > 0 ? contentTypes[0] : "application/json";
+
+    if (contentType.startsWith("multipart/form-data")) {
+      // file uploading
+      MultipartEntityBuilder builder = MultipartEntityBuilder.create();
+      
+
+      HttpEntity httpEntity = builder.build();
+      postBody = httpEntity;
+    } else {
+      // normal form params
+      
+    }
 
     try {
-      String response = apiInvoker.invokeAPI(basePath, path, "GET", queryParams, postBody, headerParams, contentType);
+      String response = apiInvoker.invokeAPI(basePath, path, "GET", queryParams, postBody, headerParams, formParams, contentType);
       if(response != null){
         return (List<Pet>) ApiInvoker.deserialize(response, "array", Pet.class);
       }
@@ -159,18 +216,36 @@ public class PetApi {
 
     // query params
     Map<String, String> queryParams = new HashMap<String, String>();
+    // header params
     Map<String, String> headerParams = new HashMap<String, String>();
+    // form params
+    Map<String, String> formParams = new HashMap<String, String>();
 
-    if(!"null".equals(String.valueOf(tags)))
-      queryParams.put("tags", String.valueOf(tags));
+    if (tags != null)
+      queryParams.put("tags", ApiInvoker.parameterToString(tags));
     
 
     
 
-    String contentType = "application/json";
+    String[] contentTypes = {
+      
+    };
+    String contentType = contentTypes.length > 0 ? contentTypes[0] : "application/json";
+
+    if (contentType.startsWith("multipart/form-data")) {
+      // file uploading
+      MultipartEntityBuilder builder = MultipartEntityBuilder.create();
+      
+
+      HttpEntity httpEntity = builder.build();
+      postBody = httpEntity;
+    } else {
+      // normal form params
+      
+    }
 
     try {
-      String response = apiInvoker.invokeAPI(basePath, path, "GET", queryParams, postBody, headerParams, contentType);
+      String response = apiInvoker.invokeAPI(basePath, path, "GET", queryParams, postBody, headerParams, formParams, contentType);
       if(response != null){
         return (List<Pet>) ApiInvoker.deserialize(response, "array", Pet.class);
       }
@@ -198,16 +273,34 @@ public class PetApi {
 
     // query params
     Map<String, String> queryParams = new HashMap<String, String>();
+    // header params
     Map<String, String> headerParams = new HashMap<String, String>();
+    // form params
+    Map<String, String> formParams = new HashMap<String, String>();
 
     
 
     
 
-    String contentType = "application/json";
+    String[] contentTypes = {
+      
+    };
+    String contentType = contentTypes.length > 0 ? contentTypes[0] : "application/json";
+
+    if (contentType.startsWith("multipart/form-data")) {
+      // file uploading
+      MultipartEntityBuilder builder = MultipartEntityBuilder.create();
+      
+
+      HttpEntity httpEntity = builder.build();
+      postBody = httpEntity;
+    } else {
+      // normal form params
+      
+    }
 
     try {
-      String response = apiInvoker.invokeAPI(basePath, path, "GET", queryParams, postBody, headerParams, contentType);
+      String response = apiInvoker.invokeAPI(basePath, path, "GET", queryParams, postBody, headerParams, formParams, contentType);
       if(response != null){
         return (Pet) ApiInvoker.deserialize(response, "", Pet.class);
       }
@@ -235,16 +328,44 @@ public class PetApi {
 
     // query params
     Map<String, String> queryParams = new HashMap<String, String>();
+    // header params
     Map<String, String> headerParams = new HashMap<String, String>();
+    // form params
+    Map<String, String> formParams = new HashMap<String, String>();
 
     
 
     
 
-    String contentType = "application/json";
+    String[] contentTypes = {
+      "application/x-www-form-urlencoded"
+    };
+    String contentType = contentTypes.length > 0 ? contentTypes[0] : "application/json";
+
+    if (contentType.startsWith("multipart/form-data")) {
+      // file uploading
+      MultipartEntityBuilder builder = MultipartEntityBuilder.create();
+      
+      if (name != null) {
+        builder.addTextBody("name", ApiInvoker.parameterToString(name), ApiInvoker.TEXT_PLAIN_UTF8);
+      }
+      
+      if (status != null) {
+        builder.addTextBody("status", ApiInvoker.parameterToString(status), ApiInvoker.TEXT_PLAIN_UTF8);
+      }
+      
+
+      HttpEntity httpEntity = builder.build();
+      postBody = httpEntity;
+    } else {
+      // normal form params
+      formParams.put("name", ApiInvoker.parameterToString(name));
+      formParams.put("status", ApiInvoker.parameterToString(status));
+      
+    }
 
     try {
-      String response = apiInvoker.invokeAPI(basePath, path, "POST", queryParams, postBody, headerParams, contentType);
+      String response = apiInvoker.invokeAPI(basePath, path, "POST", queryParams, postBody, headerParams, formParams, contentType);
       if(response != null){
         return ;
       }
@@ -272,17 +393,35 @@ public class PetApi {
 
     // query params
     Map<String, String> queryParams = new HashMap<String, String>();
+    // header params
     Map<String, String> headerParams = new HashMap<String, String>();
+    // form params
+    Map<String, String> formParams = new HashMap<String, String>();
 
     
 
-    headerParams.put("api_key", api_key);
+    headerParams.put("api_key", ApiInvoker.parameterToString(api_key));
     
 
-    String contentType = "application/json";
+    String[] contentTypes = {
+      
+    };
+    String contentType = contentTypes.length > 0 ? contentTypes[0] : "application/json";
+
+    if (contentType.startsWith("multipart/form-data")) {
+      // file uploading
+      MultipartEntityBuilder builder = MultipartEntityBuilder.create();
+      
+
+      HttpEntity httpEntity = builder.build();
+      postBody = httpEntity;
+    } else {
+      // normal form params
+      
+    }
 
     try {
-      String response = apiInvoker.invokeAPI(basePath, path, "DELETE", queryParams, postBody, headerParams, contentType);
+      String response = apiInvoker.invokeAPI(basePath, path, "DELETE", queryParams, postBody, headerParams, formParams, contentType);
       if(response != null){
         return ;
       }
@@ -310,16 +449,44 @@ public class PetApi {
 
     // query params
     Map<String, String> queryParams = new HashMap<String, String>();
+    // header params
     Map<String, String> headerParams = new HashMap<String, String>();
+    // form params
+    Map<String, String> formParams = new HashMap<String, String>();
 
     
 
     
 
-    String contentType = "application/json";
+    String[] contentTypes = {
+      "multipart/form-data"
+    };
+    String contentType = contentTypes.length > 0 ? contentTypes[0] : "application/json";
+
+    if (contentType.startsWith("multipart/form-data")) {
+      // file uploading
+      MultipartEntityBuilder builder = MultipartEntityBuilder.create();
+      
+      if (additionalMetadata != null) {
+        builder.addTextBody("additionalMetadata", ApiInvoker.parameterToString(additionalMetadata), ApiInvoker.TEXT_PLAIN_UTF8);
+      }
+      
+      if (file != null) {
+        builder.addBinaryBody("file", file);
+      }
+      
+
+      HttpEntity httpEntity = builder.build();
+      postBody = httpEntity;
+    } else {
+      // normal form params
+      formParams.put("additionalMetadata", ApiInvoker.parameterToString(additionalMetadata));
+      
+      
+    }
 
     try {
-      String response = apiInvoker.invokeAPI(basePath, path, "POST", queryParams, postBody, headerParams, contentType);
+      String response = apiInvoker.invokeAPI(basePath, path, "POST", queryParams, postBody, headerParams, formParams, contentType);
       if(response != null){
         return ;
       }
diff --git a/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/StoreApi.java b/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/StoreApi.java
index bdbce53ba3f6..b68af58ce9da 100644
--- a/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/StoreApi.java
+++ b/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/StoreApi.java
@@ -10,6 +10,9 @@ import java.util.*;
 import java.util.Map;
 import io.swagger.client.model.Order;
 
+import org.apache.http.HttpEntity;
+import org.apache.http.entity.mime.MultipartEntityBuilder;
+
 import java.util.Map;
 import java.util.HashMap;
 import java.io.File;
@@ -46,16 +49,34 @@ public class StoreApi {
 
     // query params
     Map<String, String> queryParams = new HashMap<String, String>();
+    // header params
     Map<String, String> headerParams = new HashMap<String, String>();
+    // form params
+    Map<String, String> formParams = new HashMap<String, String>();
 
     
 
     
 
-    String contentType = "application/json";
+    String[] contentTypes = {
+      
+    };
+    String contentType = contentTypes.length > 0 ? contentTypes[0] : "application/json";
+
+    if (contentType.startsWith("multipart/form-data")) {
+      // file uploading
+      MultipartEntityBuilder builder = MultipartEntityBuilder.create();
+      
+
+      HttpEntity httpEntity = builder.build();
+      postBody = httpEntity;
+    } else {
+      // normal form params
+      
+    }
 
     try {
-      String response = apiInvoker.invokeAPI(basePath, path, "GET", queryParams, postBody, headerParams, contentType);
+      String response = apiInvoker.invokeAPI(basePath, path, "GET", queryParams, postBody, headerParams, formParams, contentType);
       if(response != null){
         return (Map<String, Integer>) ApiInvoker.deserialize(response, "map", Map.class);
       }
@@ -83,16 +104,34 @@ public class StoreApi {
 
     // query params
     Map<String, String> queryParams = new HashMap<String, String>();
+    // header params
     Map<String, String> headerParams = new HashMap<String, String>();
+    // form params
+    Map<String, String> formParams = new HashMap<String, String>();
 
     
 
     
 
-    String contentType = "application/json";
+    String[] contentTypes = {
+      
+    };
+    String contentType = contentTypes.length > 0 ? contentTypes[0] : "application/json";
+
+    if (contentType.startsWith("multipart/form-data")) {
+      // file uploading
+      MultipartEntityBuilder builder = MultipartEntityBuilder.create();
+      
+
+      HttpEntity httpEntity = builder.build();
+      postBody = httpEntity;
+    } else {
+      // normal form params
+      
+    }
 
     try {
-      String response = apiInvoker.invokeAPI(basePath, path, "POST", queryParams, postBody, headerParams, contentType);
+      String response = apiInvoker.invokeAPI(basePath, path, "POST", queryParams, postBody, headerParams, formParams, contentType);
       if(response != null){
         return (Order) ApiInvoker.deserialize(response, "", Order.class);
       }
@@ -120,16 +159,34 @@ public class StoreApi {
 
     // query params
     Map<String, String> queryParams = new HashMap<String, String>();
+    // header params
     Map<String, String> headerParams = new HashMap<String, String>();
+    // form params
+    Map<String, String> formParams = new HashMap<String, String>();
 
     
 
     
 
-    String contentType = "application/json";
+    String[] contentTypes = {
+      
+    };
+    String contentType = contentTypes.length > 0 ? contentTypes[0] : "application/json";
+
+    if (contentType.startsWith("multipart/form-data")) {
+      // file uploading
+      MultipartEntityBuilder builder = MultipartEntityBuilder.create();
+      
+
+      HttpEntity httpEntity = builder.build();
+      postBody = httpEntity;
+    } else {
+      // normal form params
+      
+    }
 
     try {
-      String response = apiInvoker.invokeAPI(basePath, path, "GET", queryParams, postBody, headerParams, contentType);
+      String response = apiInvoker.invokeAPI(basePath, path, "GET", queryParams, postBody, headerParams, formParams, contentType);
       if(response != null){
         return (Order) ApiInvoker.deserialize(response, "", Order.class);
       }
@@ -157,16 +214,34 @@ public class StoreApi {
 
     // query params
     Map<String, String> queryParams = new HashMap<String, String>();
+    // header params
     Map<String, String> headerParams = new HashMap<String, String>();
+    // form params
+    Map<String, String> formParams = new HashMap<String, String>();
 
     
 
     
 
-    String contentType = "application/json";
+    String[] contentTypes = {
+      
+    };
+    String contentType = contentTypes.length > 0 ? contentTypes[0] : "application/json";
+
+    if (contentType.startsWith("multipart/form-data")) {
+      // file uploading
+      MultipartEntityBuilder builder = MultipartEntityBuilder.create();
+      
+
+      HttpEntity httpEntity = builder.build();
+      postBody = httpEntity;
+    } else {
+      // normal form params
+      
+    }
 
     try {
-      String response = apiInvoker.invokeAPI(basePath, path, "DELETE", queryParams, postBody, headerParams, contentType);
+      String response = apiInvoker.invokeAPI(basePath, path, "DELETE", queryParams, postBody, headerParams, formParams, contentType);
       if(response != null){
         return ;
       }
diff --git a/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/UserApi.java b/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/UserApi.java
index 0328a002bf24..aea620104a99 100644
--- a/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/UserApi.java
+++ b/samples/client/petstore/android-java/src/main/java/io/swagger/client/api/UserApi.java
@@ -10,6 +10,9 @@ import java.util.*;
 import io.swagger.client.model.User;
 import java.util.*;
 
+import org.apache.http.HttpEntity;
+import org.apache.http.entity.mime.MultipartEntityBuilder;
+
 import java.util.Map;
 import java.util.HashMap;
 import java.io.File;
@@ -46,16 +49,34 @@ public class UserApi {
 
     // query params
     Map<String, String> queryParams = new HashMap<String, String>();
+    // header params
     Map<String, String> headerParams = new HashMap<String, String>();
+    // form params
+    Map<String, String> formParams = new HashMap<String, String>();
 
     
 
     
 
-    String contentType = "application/json";
+    String[] contentTypes = {
+      
+    };
+    String contentType = contentTypes.length > 0 ? contentTypes[0] : "application/json";
+
+    if (contentType.startsWith("multipart/form-data")) {
+      // file uploading
+      MultipartEntityBuilder builder = MultipartEntityBuilder.create();
+      
+
+      HttpEntity httpEntity = builder.build();
+      postBody = httpEntity;
+    } else {
+      // normal form params
+      
+    }
 
     try {
-      String response = apiInvoker.invokeAPI(basePath, path, "POST", queryParams, postBody, headerParams, contentType);
+      String response = apiInvoker.invokeAPI(basePath, path, "POST", queryParams, postBody, headerParams, formParams, contentType);
       if(response != null){
         return ;
       }
@@ -83,16 +104,34 @@ public class UserApi {
 
     // query params
     Map<String, String> queryParams = new HashMap<String, String>();
+    // header params
     Map<String, String> headerParams = new HashMap<String, String>();
+    // form params
+    Map<String, String> formParams = new HashMap<String, String>();
 
     
 
     
 
-    String contentType = "application/json";
+    String[] contentTypes = {
+      
+    };
+    String contentType = contentTypes.length > 0 ? contentTypes[0] : "application/json";
+
+    if (contentType.startsWith("multipart/form-data")) {
+      // file uploading
+      MultipartEntityBuilder builder = MultipartEntityBuilder.create();
+      
+
+      HttpEntity httpEntity = builder.build();
+      postBody = httpEntity;
+    } else {
+      // normal form params
+      
+    }
 
     try {
-      String response = apiInvoker.invokeAPI(basePath, path, "POST", queryParams, postBody, headerParams, contentType);
+      String response = apiInvoker.invokeAPI(basePath, path, "POST", queryParams, postBody, headerParams, formParams, contentType);
       if(response != null){
         return ;
       }
@@ -120,16 +159,34 @@ public class UserApi {
 
     // query params
     Map<String, String> queryParams = new HashMap<String, String>();
+    // header params
     Map<String, String> headerParams = new HashMap<String, String>();
+    // form params
+    Map<String, String> formParams = new HashMap<String, String>();
 
     
 
     
 
-    String contentType = "application/json";
+    String[] contentTypes = {
+      
+    };
+    String contentType = contentTypes.length > 0 ? contentTypes[0] : "application/json";
+
+    if (contentType.startsWith("multipart/form-data")) {
+      // file uploading
+      MultipartEntityBuilder builder = MultipartEntityBuilder.create();
+      
+
+      HttpEntity httpEntity = builder.build();
+      postBody = httpEntity;
+    } else {
+      // normal form params
+      
+    }
 
     try {
-      String response = apiInvoker.invokeAPI(basePath, path, "POST", queryParams, postBody, headerParams, contentType);
+      String response = apiInvoker.invokeAPI(basePath, path, "POST", queryParams, postBody, headerParams, formParams, contentType);
       if(response != null){
         return ;
       }
@@ -157,20 +214,38 @@ public class UserApi {
 
     // query params
     Map<String, String> queryParams = new HashMap<String, String>();
+    // header params
     Map<String, String> headerParams = new HashMap<String, String>();
+    // form params
+    Map<String, String> formParams = new HashMap<String, String>();
 
-    if(!"null".equals(String.valueOf(username)))
-      queryParams.put("username", String.valueOf(username));
-    if(!"null".equals(String.valueOf(password)))
-      queryParams.put("password", String.valueOf(password));
+    if (username != null)
+      queryParams.put("username", ApiInvoker.parameterToString(username));
+    if (password != null)
+      queryParams.put("password", ApiInvoker.parameterToString(password));
     
 
     
 
-    String contentType = "application/json";
+    String[] contentTypes = {
+      
+    };
+    String contentType = contentTypes.length > 0 ? contentTypes[0] : "application/json";
+
+    if (contentType.startsWith("multipart/form-data")) {
+      // file uploading
+      MultipartEntityBuilder builder = MultipartEntityBuilder.create();
+      
+
+      HttpEntity httpEntity = builder.build();
+      postBody = httpEntity;
+    } else {
+      // normal form params
+      
+    }
 
     try {
-      String response = apiInvoker.invokeAPI(basePath, path, "GET", queryParams, postBody, headerParams, contentType);
+      String response = apiInvoker.invokeAPI(basePath, path, "GET", queryParams, postBody, headerParams, formParams, contentType);
       if(response != null){
         return (String) ApiInvoker.deserialize(response, "", String.class);
       }
@@ -198,16 +273,34 @@ public class UserApi {
 
     // query params
     Map<String, String> queryParams = new HashMap<String, String>();
+    // header params
     Map<String, String> headerParams = new HashMap<String, String>();
+    // form params
+    Map<String, String> formParams = new HashMap<String, String>();
 
     
 
     
 
-    String contentType = "application/json";
+    String[] contentTypes = {
+      
+    };
+    String contentType = contentTypes.length > 0 ? contentTypes[0] : "application/json";
+
+    if (contentType.startsWith("multipart/form-data")) {
+      // file uploading
+      MultipartEntityBuilder builder = MultipartEntityBuilder.create();
+      
+
+      HttpEntity httpEntity = builder.build();
+      postBody = httpEntity;
+    } else {
+      // normal form params
+      
+    }
 
     try {
-      String response = apiInvoker.invokeAPI(basePath, path, "GET", queryParams, postBody, headerParams, contentType);
+      String response = apiInvoker.invokeAPI(basePath, path, "GET", queryParams, postBody, headerParams, formParams, contentType);
       if(response != null){
         return ;
       }
@@ -235,16 +328,34 @@ public class UserApi {
 
     // query params
     Map<String, String> queryParams = new HashMap<String, String>();
+    // header params
     Map<String, String> headerParams = new HashMap<String, String>();
+    // form params
+    Map<String, String> formParams = new HashMap<String, String>();
 
     
 
     
 
-    String contentType = "application/json";
+    String[] contentTypes = {
+      
+    };
+    String contentType = contentTypes.length > 0 ? contentTypes[0] : "application/json";
+
+    if (contentType.startsWith("multipart/form-data")) {
+      // file uploading
+      MultipartEntityBuilder builder = MultipartEntityBuilder.create();
+      
+
+      HttpEntity httpEntity = builder.build();
+      postBody = httpEntity;
+    } else {
+      // normal form params
+      
+    }
 
     try {
-      String response = apiInvoker.invokeAPI(basePath, path, "GET", queryParams, postBody, headerParams, contentType);
+      String response = apiInvoker.invokeAPI(basePath, path, "GET", queryParams, postBody, headerParams, formParams, contentType);
       if(response != null){
         return (User) ApiInvoker.deserialize(response, "", User.class);
       }
@@ -272,16 +383,34 @@ public class UserApi {
 
     // query params
     Map<String, String> queryParams = new HashMap<String, String>();
+    // header params
     Map<String, String> headerParams = new HashMap<String, String>();
+    // form params
+    Map<String, String> formParams = new HashMap<String, String>();
 
     
 
     
 
-    String contentType = "application/json";
+    String[] contentTypes = {
+      
+    };
+    String contentType = contentTypes.length > 0 ? contentTypes[0] : "application/json";
+
+    if (contentType.startsWith("multipart/form-data")) {
+      // file uploading
+      MultipartEntityBuilder builder = MultipartEntityBuilder.create();
+      
+
+      HttpEntity httpEntity = builder.build();
+      postBody = httpEntity;
+    } else {
+      // normal form params
+      
+    }
 
     try {
-      String response = apiInvoker.invokeAPI(basePath, path, "PUT", queryParams, postBody, headerParams, contentType);
+      String response = apiInvoker.invokeAPI(basePath, path, "PUT", queryParams, postBody, headerParams, formParams, contentType);
       if(response != null){
         return ;
       }
@@ -309,16 +438,34 @@ public class UserApi {
 
     // query params
     Map<String, String> queryParams = new HashMap<String, String>();
+    // header params
     Map<String, String> headerParams = new HashMap<String, String>();
+    // form params
+    Map<String, String> formParams = new HashMap<String, String>();
 
     
 
     
 
-    String contentType = "application/json";
+    String[] contentTypes = {
+      
+    };
+    String contentType = contentTypes.length > 0 ? contentTypes[0] : "application/json";
+
+    if (contentType.startsWith("multipart/form-data")) {
+      // file uploading
+      MultipartEntityBuilder builder = MultipartEntityBuilder.create();
+      
+
+      HttpEntity httpEntity = builder.build();
+      postBody = httpEntity;
+    } else {
+      // normal form params
+      
+    }
 
     try {
-      String response = apiInvoker.invokeAPI(basePath, path, "DELETE", queryParams, postBody, headerParams, contentType);
+      String response = apiInvoker.invokeAPI(basePath, path, "DELETE", queryParams, postBody, headerParams, formParams, contentType);
       if(response != null){
         return ;
       }