[Java][client] make it possible to send explicit nulls for nullable fields (#3474)

* [Java][client] make it possible to send explicit nulls for nullable fields

* Regenerate samples

modules/openapi-generator-maven-plugin/examples/java-client.xml

@@ -120,7 +120,12 @@
           <groupId>com.fasterxml.jackson.jaxrs</groupId>
           <artifactId>jackson-jaxrs-json-provider</artifactId>
           <version>${jackson-version}</version>
-        </dependency>
+      </dependency>
+      <dependency>
+          <groupId>org.openapitools</groupId>
+          <artifactId>jackson-databind-nullable</artifactId>
+          <version>${jackson-databind-nullable-version}</version>
+      </dependency>
 
         <!-- Joda time: if you use it -->
         <dependency>
@@ -146,6 +151,7 @@
         <swagger-annotations-version>1.5.8</swagger-annotations-version>
         <jersey-version>2.27</jersey-version>
         <jackson-version>2.8.9</jackson-version>
+        <jackson-databind-nullable-version>0.2.0</jackson-databind-nullable-version>
         <jodatime-version>2.7</jodatime-version>
         <maven-plugin-version>1.0.0</maven-plugin-version>
         <junit-version>4.8.1</junit-version>

modules/openapi-generator-maven-plugin/examples/multi-module/java-client/pom.xml

@@ -133,7 +133,12 @@
           <groupId>com.fasterxml.jackson.jaxrs</groupId>
           <artifactId>jackson-jaxrs-json-provider</artifactId>
           <version>${jackson-version}</version>
-        </dependency>
+      </dependency>
+      <dependency>
+          <groupId>org.openapitools</groupId>
+          <artifactId>jackson-databind-nullable</artifactId>
+          <version>${jackson-databind-nullable-version}</version>
+      </dependency>
 
         <!-- Joda time: if you use it -->
         <dependency>

modules/openapi-generator-maven-plugin/examples/multi-module/pom.xml

@@ -16,6 +16,7 @@
         <swagger-annotations-version>1.5.8</swagger-annotations-version>
         <jersey-version>2.27</jersey-version>
         <jackson-version>2.8.9</jackson-version>
+        <jackson-databind-nullable-version>0.2.0</jackson-databind-nullable-version>
         <jodatime-version>2.7</jodatime-version>
         <maven-plugin-version>1.0.0</maven-plugin-version>
         <junit-version>4.8.1</junit-version>

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java

@@ -417,6 +417,8 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
         importMapping.put("JsonTypeInfo", "com.fasterxml.jackson.annotation.JsonTypeInfo");
         importMapping.put("JsonCreator", "com.fasterxml.jackson.annotation.JsonCreator");
         importMapping.put("JsonValue", "com.fasterxml.jackson.annotation.JsonValue");
+        importMapping.put("JsonIgnore", "com.fasterxml.jackson.annotation.JsonIgnore");
+        importMapping.put("JsonInclude", "com.fasterxml.jackson.annotation.JsonInclude");
         importMapping.put("SerializedName", "com.google.gson.annotations.SerializedName");
         importMapping.put("TypeAdapter", "com.google.gson.TypeAdapter");
         importMapping.put("JsonAdapter", "com.google.gson.annotations.JsonAdapter");
@@ -800,7 +802,13 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
                 }
             }
             return null;
+        } else if (ModelUtils.isObjectSchema(p)) {
+            if (p.getDefault() != null) {
+                return super.toDefaultValue(p);
+            }
+            return null;
         }
+
         return super.toDefaultValue(p);
     }
 

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaClientCodegen.java

@@ -24,6 +24,7 @@ import org.openapitools.codegen.languages.features.BeanValidationFeatures;
 import org.openapitools.codegen.languages.features.GzipFeatures;
 import org.openapitools.codegen.languages.features.PerformBeanValidationFeatures;
 import org.openapitools.codegen.templating.mustache.CaseFormatLambda;
+import org.openapitools.codegen.utils.ModelUtils;
 import org.openapitools.codegen.utils.ProcessUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -583,6 +584,7 @@ public class JavaClientCodegen extends AbstractJavaCodegen
             if (additionalProperties.containsKey("jackson")) {
                 model.imports.add("JsonProperty");
                 model.imports.add("JsonValue");
+                model.imports.add("JsonInclude");
             }
             if (additionalProperties.containsKey("gson")) {
                 model.imports.add("SerializedName");
@@ -623,6 +625,39 @@ public class JavaClientCodegen extends AbstractJavaCodegen
         return objs;
     }
 
+    @Override
+    public Map<String, Object> postProcessModels(Map<String, Object> objs) {
+        objs = super.postProcessModels(objs);
+        if (additionalProperties.containsKey("jackson") && !JERSEY1.equals(getLibrary())) {
+            List<Map<String, String>> imports = (List<Map<String, String>>) objs.get("imports");
+            List<Object> models = (List<Object>) objs.get("models");
+            for (Object _mo : models) {
+                Map<String, Object> mo = (Map<String, Object>) _mo;
+                CodegenModel cm = (CodegenModel) mo.get("model");
+                boolean addImports = false;
+                for (CodegenProperty var : cm.vars) {
+                    boolean isOptionalNullable = Boolean.FALSE.equals(var.required) && Boolean.TRUE.equals(var.isNullable);
+                    // only add JsonNullable and related imports to optional and nullable values
+                    addImports |= isOptionalNullable;
+                    var.getVendorExtensions().put("isJacksonOptionalNullable", isOptionalNullable);
+                }
+                if (addImports) {
+                    cm.imports.add("JsonNullable");
+                    Map<String, String> itemJsonNullable = new HashMap<String, String>();
+                    itemJsonNullable.put("import", "org.openapitools.jackson.nullable.JsonNullable");
+                    imports.add(itemJsonNullable);
+
+                    cm.imports.add("NoSuchElementException");
+                    Map<String, String> itemExc = new HashMap<String, String>();
+                    itemExc.put("import", "java.util.NoSuchElementException");
+                    imports.add(itemExc);
+                }
+            }
+        }
+
+        return objs;
+    }
+
     public void setUseRxJava(boolean useRxJava) {
         this.useRxJava = useRxJava;
         doNotUseRx = false;

modules/openapi-generator/src/main/resources/Java/jackson_annotations.mustache

@@ -0,0 +1,19 @@
+{{!
+ If this is map and items are nullable, make sure that nulls are included.
+ To determine what JsonInclude.Include method to use, consider the following:
+ * If the field is required, always include it, even if it is null.
+ * Else use custom behaviour, IOW use whatever is defined on the object mapper
+ }}
+  @JsonProperty(JSON_PROPERTY_{{nameInSnakeCase}})
+  @JsonInclude({{#isMapContainer}}{{#items.isNullable}}content = JsonInclude.Include.ALWAYS, {{/items.isNullable}}{{/isMapContainer}}value = JsonInclude.Include.{{#required}}ALWAYS{{/required}}{{^required}}USE_DEFAULTS{{/required}})
+  {{#withXml}}
+    {{^isContainer}}
+  @JacksonXmlProperty({{#isXmlAttribute}}isAttribute = true, {{/isXmlAttribute}}{{#xmlNamespace}}namespace="{{xmlNamespace}}", {{/xmlNamespace}}localName = "{{#xmlName}}{{xmlName}}{{/xmlName}}{{^xmlName}}{{baseName}}{{/xmlName}}")
+    {{/isContainer}}
+    {{#isContainer}}
+      {{#isXmlWrapped}}
+  // items.xmlName={{items.xmlName}}
+  @JacksonXmlElementWrapper(useWrapping = {{isXmlWrapped}}, {{#xmlNamespace}}namespace="{{xmlNamespace}}", {{/xmlNamespace}}localName = "{{#items.xmlName}}{{items.xmlName}}{{/items.xmlName}}{{^items.xmlName}}{{items.baseName}}{{/items.xmlName}}")
+      {{/isXmlWrapped}}
+    {{/isContainer}}
+  {{/withXml}}

modules/openapi-generator/src/main/resources/Java/libraries/feign/ApiClient.mustache

@@ -12,6 +12,7 @@ import org.threeten.bp.*;
 import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.SerializationFeature;
+import org.openapitools.jackson.nullable.JsonNullableModule;
 {{#joda}}
 import com.fasterxml.jackson.datatype.joda.JodaModule;
 {{/joda}}
@@ -177,6 +178,8 @@ public class ApiClient {
     module.addDeserializer(ZonedDateTime.class, CustomInstantDeserializer.ZONED_DATE_TIME);
     objectMapper.registerModule(module);
     {{/threetenbp}}
+    JsonNullableModule jnm = new JsonNullableModule();
+    objectMapper.registerModule(jnm);
     return objectMapper;
   }
 

modules/openapi-generator/src/main/resources/Java/libraries/feign/pom.mustache

@@ -244,6 +244,11 @@
             <artifactId>jackson-databind</artifactId>
             <version>${jackson-databind-version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.openapitools</groupId>
+            <artifactId>jackson-databind-nullable</artifactId>
+            <version>${jackson-databind-nullable-version}</version>
+        </dependency>
         {{#withXml}}
 
             <!-- XML Support -->
@@ -310,6 +315,7 @@
         <feign-version>{{#useFeign10}}10.2.3{{/useFeign10}}{{^useFeign10}}9.7.0{{/useFeign10}}</feign-version>
         <feign-form-version>2.1.0</feign-form-version>
         <jackson-version>2.9.9</jackson-version>
+        <jackson-databind-nullable-version>0.2.0</jackson-databind-nullable-version>
         <jackson-databind-version>2.9.9</jackson-databind-version>
         {{#threetenbp}}
         <jackson-threetenbp-version>2.6.4</jackson-threetenbp-version>

modules/openapi-generator/src/main/resources/Java/libraries/google-api-client/ApiClient.mustache

@@ -4,6 +4,7 @@ import {{apiPackage}}.*;
 import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.SerializationFeature;
+import org.openapitools.jackson.nullable.JsonNullableModule;
 {{#joda}}
 import com.fasterxml.jackson.datatype.joda.JodaModule;
 {{/joda}}
@@ -53,6 +54,8 @@ public class ApiClient {
         module.addDeserializer(ZonedDateTime.class, CustomInstantDeserializer.ZONED_DATE_TIME);
         objectMapper.registerModule(module);
         {{/threetenbp}}
+        JsonNullableModule jnm = new JsonNullableModule();
+        objectMapper.registerModule(jnm);
         return objectMapper;
     }
 

modules/openapi-generator/src/main/resources/Java/libraries/google-api-client/pom.mustache

@@ -253,6 +253,11 @@
             <artifactId>jackson-databind</artifactId>
             <version>${jackson-version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.openapitools</groupId>
+            <artifactId>jackson-databind-nullable</artifactId>
+            <version>${jackson-databind-nullable-version}</version>
+        </dependency>
         {{#withXml}}
             <!-- XML processing: Jackson -->
             <dependency>
@@ -303,6 +308,7 @@
         <jersey-common-version>2.25.1</jersey-common-version>
         <jackson-version>2.9.9</jackson-version>
         <jackson-databind-version>2.9.9</jackson-databind-version>
+        <jackson-databind-nullable-version>0.2.0</jackson-databind-nullable-version>
         {{#joda}}
         <jodatime-version>2.9.9</jodatime-version>
         {{/joda}}

modules/openapi-generator/src/main/resources/Java/libraries/jersey2/JSON.mustache

@@ -5,6 +5,7 @@ import org.threeten.bp.*;
 {{/threetenbp}}
 import com.fasterxml.jackson.annotation.*;
 import com.fasterxml.jackson.databind.*;
+import org.openapitools.jackson.nullable.JsonNullableModule;
 {{#java8}}
 import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
 {{/java8}}
@@ -45,6 +46,8 @@ public class JSON implements ContextResolver<ObjectMapper> {
     module.addDeserializer(ZonedDateTime.class, CustomInstantDeserializer.ZONED_DATE_TIME);
     mapper.registerModule(module);
     {{/threetenbp}}
+    JsonNullableModule jnm = new JsonNullableModule();
+    mapper.registerModule(jnm);
   }
 
   /**

modules/openapi-generator/src/main/resources/Java/libraries/jersey2/pom.mustache

@@ -276,6 +276,11 @@
             <artifactId>jackson-databind</artifactId>
             <version>${jackson-databind-version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.openapitools</groupId>
+            <artifactId>jackson-databind-nullable</artifactId>
+            <version>${jackson-databind-nullable-version}</version>
+        </dependency>
         {{#withXml}}
 
             <!-- XML processing: JAXB -->
@@ -357,6 +362,7 @@
         {{/supportJava6}}
         <jackson-version>2.9.9</jackson-version>
         <jackson-databind-version>2.9.9</jackson-databind-version>
+        <jackson-databind-nullable-version>0.2.0</jackson-databind-nullable-version>
         {{#threetenbp}}
         <threetenbp-version>2.6.4</threetenbp-version>
         {{/threetenbp}}

modules/openapi-generator/src/main/resources/Java/libraries/native/ApiClient.mustache

@@ -6,6 +6,7 @@ import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.SerializationFeature;
 import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
+import org.openapitools.jackson.nullable.JsonNullableModule;
 
 import java.net.URI;
 import java.net.URLEncoder;
@@ -151,6 +152,8 @@ public class ApiClient {
     mapper.enable(SerializationFeature.WRITE_ENUMS_USING_TO_STRING);
     mapper.enable(DeserializationFeature.READ_ENUMS_USING_TO_STRING);
     mapper.registerModule(new JavaTimeModule());
+    JsonNullableModule jnm = new JsonNullableModule();
+    mapper.registerModule(jnm);
     URI baseURI = URI.create("{{{basePath}}}");
     scheme = baseURI.getScheme();
     host = baseURI.getHost();

modules/openapi-generator/src/main/resources/Java/libraries/native/pom.mustache

@@ -188,6 +188,11 @@
             <artifactId>jackson-datatype-jsr310</artifactId>
             <version>${jackson-version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.openapitools</groupId>
+            <artifactId>jackson-databind-nullable</artifactId>
+            <version>${jackson-databind-nullable-version}</version>
+        </dependency>
 
         <!-- @Nullable annotation -->
         <dependency>
@@ -210,6 +215,7 @@
         <maven.compiler.source>11</maven.compiler.source>
         <maven.compiler.target>11</maven.compiler.target>
         <jackson-version>2.9.9</jackson-version>
+        <jackson-databind-nullable-version>0.2.0</jackson-databind-nullable-version>
         <junit-version>4.12</junit-version>
     </properties>
 </project>

modules/openapi-generator/src/main/resources/Java/libraries/resteasy/JSON.mustache

@@ -2,6 +2,7 @@ package {{invokerPackage}};
 
 import com.fasterxml.jackson.annotation.*;
 import com.fasterxml.jackson.databind.*;
+import org.openapitools.jackson.nullable.JsonNullableModule;
 {{#java8}}
 import com.fasterxml.jackson.datatype.jsr310.*;
 {{/java8}}
@@ -26,6 +27,8 @@ public class JSON implements ContextResolver<ObjectMapper> {
     mapper.enable(SerializationFeature.WRITE_ENUMS_USING_TO_STRING);
     mapper.enable(DeserializationFeature.READ_ENUMS_USING_TO_STRING);
     mapper.setDateFormat(new RFC3339DateFormat());
+    JsonNullableModule jnm = new JsonNullableModule();
+    mapper.registerModule(jnm);
     {{#java8}}
     mapper.registerModule(new JavaTimeModule());
     {{/java8}}

modules/openapi-generator/src/main/resources/Java/libraries/resteasy/pom.mustache

@@ -212,6 +212,11 @@
             <artifactId>jackson-databind</artifactId>
             <version>${jackson-databind-version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.openapitools</groupId>
+            <artifactId>jackson-databind-nullable</artifactId>
+            <version>${jackson-databind-nullable-version}</version>
+        </dependency>
         {{#withXml}}
 
         <!-- XML processing: Jackson -->
@@ -291,6 +296,7 @@
         <resteasy-version>3.1.3.Final</resteasy-version>
         <jackson-version>2.9.9</jackson-version>
         <jackson-databind-version>2.9.9</jackson-databind-version>
+        <jackson-databind-nullable-version>0.2.0</jackson-databind-nullable-version>
         <threetenbp-version>2.6.4</threetenbp-version>
         {{^java8}}
         <jodatime-version>2.9.9</jodatime-version>

modules/openapi-generator/src/main/resources/Java/libraries/resttemplate/ApiClient.mustache

@@ -39,6 +39,7 @@ import com.fasterxml.jackson.datatype.threetenbp.ThreeTenModule;
 import org.springframework.http.converter.HttpMessageConverter;
 import org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import org.openapitools.jackson.nullable.JsonNullableModule;
 {{/threetenbp}}
 
 import java.io.BufferedReader;
@@ -661,6 +662,7 @@ public class ApiClient {
         messageConverters.add(new MappingJackson2HttpMessageConverter());
         XmlMapper xmlMapper = new XmlMapper();
         xmlMapper.configure(ToXmlGenerator.Feature.WRITE_XML_DECLARATION, true);
+        xmlMapper.registerModule(new JsonNullableModule());
         messageConverters.add(new MappingJackson2XmlHttpMessageConverter(xmlMapper));
 
         RestTemplate restTemplate = new RestTemplate(messageConverters);
@@ -674,6 +676,7 @@ public class ApiClient {
                 module.addDeserializer(OffsetDateTime.class, CustomInstantDeserializer.OFFSET_DATE_TIME);
                 module.addDeserializer(ZonedDateTime.class, CustomInstantDeserializer.ZONED_DATE_TIME);
                 mapper.registerModule(module);
+                mapper.registerModule(new JsonNullableModule());
             }
         }
         {{/threetenbp}}

modules/openapi-generator/src/main/resources/Java/libraries/resttemplate/pom.mustache

@@ -255,6 +255,11 @@
             <artifactId>jackson-jaxrs-json-provider</artifactId>
             <version>${jackson-version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.openapitools</groupId>
+            <artifactId>jackson-databind-nullable</artifactId>
+            <version>${jackson-databind-nullable-version}</version>
+        </dependency>
         {{#withXml}}
 
             <!-- XML processing: Jackson -->
@@ -306,6 +311,7 @@
         <spring-web-version>4.3.9.RELEASE</spring-web-version>
         <jackson-version>2.9.9</jackson-version>
         <jackson-databind-version>2.9.9</jackson-databind-version>
+        <jackson-databind-nullable-version>0.2.0</jackson-databind-nullable-version>
         {{#joda}}
         <jodatime-version>2.9.9</jodatime-version>
         {{/joda}}

modules/openapi-generator/src/main/resources/Java/libraries/retrofit2/play24/ApiClient.mustache

@@ -8,6 +8,8 @@ import java.util.*;
 import retrofit2.Retrofit;
 import retrofit2.converter.scalars.ScalarsConverterFactory;
 import retrofit2.converter.jackson.JacksonConverterFactory;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.openapitools.jackson.nullable.JsonNullableModule;
 
 import play.libs.Json;
 import play.libs.ws.WSClient;
@@ -68,10 +70,14 @@ public class ApiClient {
             auth.applyToParams(extraQueryParams, extraHeaders);
         }
 
+        ObjectMapper mapper = Json.mapper();
+        JsonNullableModule jnm = new JsonNullableModule();
+        mapper.registerModule(jnm);
+
         return new Retrofit.Builder()
                        .baseUrl(basePath)
                        .addConverterFactory(ScalarsConverterFactory.create())
-                       .addConverterFactory(JacksonConverterFactory.create(Json.mapper()))
+                       .addConverterFactory(JacksonConverterFactory.create(mapper))
                        .callFactory(new Play24CallFactory(wsClient, extraHeaders, extraQueryParams))
                        .addCallAdapterFactory(new Play24CallAdapterFactory())
                        .build()

modules/openapi-generator/src/main/resources/Java/libraries/retrofit2/play25/ApiClient.mustache

@@ -8,6 +8,8 @@ import java.util.*;
 import retrofit2.Retrofit;
 import retrofit2.converter.scalars.ScalarsConverterFactory;
 import retrofit2.converter.jackson.JacksonConverterFactory;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.openapitools.jackson.nullable.JsonNullableModule;
 
 import play.libs.Json;
 import play.libs.ws.WSClient;
@@ -67,10 +69,14 @@ public class ApiClient {
             auth.applyToParams(extraQueryParams, extraHeaders);
         }
 
+        ObjectMapper mapper = Json.mapper();
+        JsonNullableModule jnm = new JsonNullableModule();
+        mapper.registerModule(jnm);
+
         return new Retrofit.Builder()
                        .baseUrl(basePath)
                        .addConverterFactory(ScalarsConverterFactory.create())
-                       .addConverterFactory(JacksonConverterFactory.create(Json.mapper()))
+                       .addConverterFactory(JacksonConverterFactory.create(mapper))
                        .callFactory(new Play25CallFactory(wsClient, extraHeaders, extraQueryParams))
                        .addCallAdapterFactory(new Play25CallAdapterFactory())
                        .build()

modules/openapi-generator/src/main/resources/Java/libraries/retrofit2/play26/ApiClient.mustache

@@ -13,6 +13,7 @@ import retrofit2.Converter;
 import retrofit2.Retrofit;
 import retrofit2.converter.scalars.ScalarsConverterFactory;
 import retrofit2.converter.jackson.JacksonConverterFactory;
+import org.openapitools.jackson.nullable.JsonNullableModule;
 
 import play.libs.Json;
 import play.libs.ws.WSClient;
@@ -89,6 +90,8 @@ public class ApiClient {
         }
         if (defaultMapper == null) {
             defaultMapper = Json.mapper();
+            JsonNullableModule jnm = new JsonNullableModule();
+            defaultMapper.registerModule(jnm);
         }
 
         return new Retrofit.Builder()

modules/openapi-generator/src/main/resources/Java/libraries/retrofit2/pom.mustache

@@ -314,6 +314,11 @@
                 <artifactId>play-java-ws_2.11</artifactId>
                 <version>${play-version}</version>
             </dependency>
+            <dependency>
+                <groupId>org.openapitools</groupId>
+                <artifactId>jackson-databind-nullable</artifactId>
+                <version>${jackson-databind-nullable-version}</version>
+            </dependency>
             {{/play24}}
             {{#play25}}
             <dependency>
@@ -321,6 +326,11 @@
                 <artifactId>play-java-ws_2.11</artifactId>
                 <version>${play-version}</version>
             </dependency>
+            <dependency>
+                <groupId>org.openapitools</groupId>
+                <artifactId>jackson-databind-nullable</artifactId>
+                <version>${jackson-databind-nullable-version}</version>
+            </dependency>
             {{/play25}}
             {{#play26}}
             <dependency>
@@ -333,6 +343,11 @@
                 <artifactId>validation-api</artifactId>
                 <version>1.1.0.Final</version>
             </dependency>
+            <dependency>
+                <groupId>org.openapitools</groupId>
+                <artifactId>jackson-databind-nullable</artifactId>
+                <version>${jackson-databind-nullable-version}</version>
+            </dependency>
             {{/play26}}
         {{/usePlayWS}}
         {{#parcelableModel}}
@@ -373,6 +388,7 @@
         <jackson-version>2.9.9</jackson-version>
         <play-version>2.6.7</play-version>
         {{/play26}}
+        <jackson-databind-nullable-version>0.2.0</jackson-databind-nullable-version>
         {{/usePlayWS}}
         <retrofit-version>2.5.0</retrofit-version>
         {{#useRxJava}}

modules/openapi-generator/src/main/resources/Java/libraries/vertx/ApiClient.mustache

@@ -14,6 +14,7 @@ import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.SerializationFeature;
 import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
+import org.openapitools.jackson.nullable.JsonNullableModule;
 import io.vertx.core.*;
 import io.vertx.core.buffer.Buffer;
 import io.vertx.core.file.AsyncFile;
@@ -77,6 +78,8 @@ public class ApiClient {
         this.objectMapper.enable(DeserializationFeature.READ_ENUMS_USING_TO_STRING);
         this.objectMapper.registerModule(new JavaTimeModule());
         this.objectMapper.setDateFormat(dateFormat);
+        JsonNullableModule jnm = new JsonNullableModule();
+        this.objectMapper.registerModule(jnm);
 
         // Setup authentications (key: authentication name, value: authentication).
         this.authentications = new HashMap<>();{{#authMethods}}{{#isBasic}}{{#isBasicBasic}}

modules/openapi-generator/src/main/resources/Java/libraries/vertx/pom.mustache

@@ -243,6 +243,11 @@
             <artifactId>jackson-databind</artifactId>
             <version>${jackson-databind}</version>
         </dependency>
+        <dependency>
+            <groupId>org.openapitools</groupId>
+            <artifactId>jackson-databind-nullable</artifactId>
+            <version>${jackson-databind-nullable-version}</version>
+        </dependency>
         {{#joda}}
             <dependency>
                 <groupId>com.fasterxml.jackson.datatype</groupId>
@@ -286,6 +291,7 @@
         <swagger-annotations-version>1.5.22</swagger-annotations-version>
         <jackson-version>{{^threetenbp}}2.9.9{{/threetenbp}}{{#threetenbp}}2.6.4{{/threetenbp}}</jackson-version>
         <jackson-databind>{{^threetenbp}}2.9.9{{/threetenbp}}{{#threetenbp}}2.6.4{{/threetenbp}}</jackson-databind>
+        <jackson-databind-nullable-version>0.2.0</jackson-databind-nullable-version>
         <junit-version>4.12</junit-version>
     </properties>
 </project>

modules/openapi-generator/src/main/resources/Java/libraries/webclient/ApiClient.mustache

@@ -3,6 +3,7 @@ package {{invokerPackage}};
 import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
+import org.openapitools.jackson.nullable.JsonNullableModule;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.springframework.core.ParameterizedTypeReference;
@@ -96,6 +97,8 @@ public class ApiClient {
         mapper.setDateFormat(dateFormat);
         mapper.registerModule(new JavaTimeModule());
         mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
+        JsonNullableModule jnm = new JsonNullableModule();
+        mapper.registerModule(jnm);
 
         this.webClient = buildWebClient(mapper);
         this.init();

modules/openapi-generator/src/main/resources/Java/libraries/webclient/pom.mustache

@@ -105,6 +105,11 @@
             <artifactId>jackson-databind</artifactId>
             <version>${jackson-databind-version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.openapitools</groupId>
+            <artifactId>jackson-databind-nullable</artifactId>
+            <version>${jackson-databind-nullable-version}</version>
+        </dependency>
 
         {{#java8}}
             <dependency>
@@ -140,6 +145,7 @@
         <spring-web-version>5.0.7.RELEASE</spring-web-version>
         <jackson-version>2.9.9</jackson-version>
         <jackson-databind-version>2.9.9</jackson-databind-version>
+        <jackson-databind-nullable-version>0.2.0</jackson-databind-nullable-version>
         <junit-version>4.12</junit-version>
         <reactor-version>3.1.8.RELEASE</reactor-version>
         <reactor-netty-version>0.7.8.RELEASE</reactor-netty-version>

modules/openapi-generator/src/main/resources/Java/pojo.mustache

@@ -19,21 +19,6 @@ public class {{classname}} {{#parent}}extends {{{parent}}} {{/parent}}{{#parcela
     {{/mostInnerItems}}
     {{/isContainer}}
     {{/isEnum}}
-  {{#jackson}}
-  public static final String JSON_PROPERTY_{{nameInSnakeCase}} = "{{baseName}}";
-  @JsonProperty(JSON_PROPERTY_{{nameInSnakeCase}})
-  {{#withXml}}
-    {{^isContainer}}
-  @JacksonXmlProperty({{#isXmlAttribute}}isAttribute = true, {{/isXmlAttribute}}{{#xmlNamespace}}namespace="{{xmlNamespace}}", {{/xmlNamespace}}localName = "{{#xmlName}}{{xmlName}}{{/xmlName}}{{^xmlName}}{{baseName}}{{/xmlName}}")
-    {{/isContainer}}
-    {{#isContainer}}
-      {{#isXmlWrapped}}
-  // items.xmlName={{items.xmlName}}
-  @JacksonXmlElementWrapper(useWrapping = {{isXmlWrapped}}, {{#xmlNamespace}}namespace="{{xmlNamespace}}", {{/xmlNamespace}}localName = "{{#items.xmlName}}{{items.xmlName}}{{/items.xmlName}}{{^items.xmlName}}{{items.baseName}}{{/items.xmlName}}")
-      {{/isXmlWrapped}}
-    {{/isContainer}}
-  {{/withXml}}
-  {{/jackson}}
   {{#withXml}}
   {{#isXmlAttribute}}
   @XmlAttribute(name = "{{#xmlName}}{{xmlName}}{{/xmlName}}{{^xmlName}}{{baseName}}{{/xmlName}}")
@@ -59,12 +44,25 @@ public class {{classname}} {{#parent}}extends {{{parent}}} {{/parent}}{{#parcela
   public static final String SERIALIZED_NAME_{{nameInSnakeCase}} = "{{baseName}}";
   @SerializedName(SERIALIZED_NAME_{{nameInSnakeCase}})
   {{/gson}}
+  {{#jackson}}
+  public static final String JSON_PROPERTY_{{nameInSnakeCase}} = "{{baseName}}";
+  {{/jackson}}
+  {{#vendorExtensions.isJacksonOptionalNullable}}
+  {{#isContainer}}
+  private JsonNullable<{{{datatypeWithEnum}}}> {{name}} = JsonNullable.<{{{datatypeWithEnum}}}>undefined();
+  {{/isContainer}}
+  {{^isContainer}}
+  private JsonNullable<{{{datatypeWithEnum}}}> {{name}} = JsonNullable.<{{{datatypeWithEnum}}}>{{#defaultValue}}of({{{.}}}){{/defaultValue}}{{^defaultValue}}undefined(){{/defaultValue}};
+  {{/isContainer}}
+  {{/vendorExtensions.isJacksonOptionalNullable}}
+  {{^vendorExtensions.isJacksonOptionalNullable}}
   {{#isContainer}}
   private {{{datatypeWithEnum}}} {{name}}{{#required}}{{#defaultValue}} = {{{.}}}{{/defaultValue}}{{/required}}{{^required}} = null{{/required}};
   {{/isContainer}}
   {{^isContainer}}
   private {{{datatypeWithEnum}}} {{name}}{{#defaultValue}} = {{{.}}}{{/defaultValue}};
   {{/isContainer}}
+  {{/vendorExtensions.isJacksonOptionalNullable}}
 
   {{/vars}}
   {{#parcelableModel}}
@@ -89,14 +87,28 @@ public class {{classname}} {{#parent}}extends {{{parent}}} {{/parent}}{{#parcela
   {{/gson}}
   {{/parcelableModel}}
   {{#vars}}
+
   {{^isReadOnly}}
   public {{classname}} {{name}}({{{datatypeWithEnum}}} {{name}}) {
-    this.{{name}} = {{name}};
+    {{#vendorExtensions.isJacksonOptionalNullable}}this.{{name}} = JsonNullable.<{{{datatypeWithEnum}}}>of({{name}});{{/vendorExtensions.isJacksonOptionalNullable}}
+    {{^vendorExtensions.isJacksonOptionalNullable}}this.{{name}} = {{name}};{{/vendorExtensions.isJacksonOptionalNullable}}
     return this;
   }
   {{#isListContainer}}
 
   public {{classname}} add{{nameInCamelCase}}Item({{{items.datatypeWithEnum}}} {{name}}Item) {
+    {{#vendorExtensions.isJacksonOptionalNullable}}
+    if (this.{{name}} == null || !this.{{name}}.isPresent()) {
+      this.{{name}} = JsonNullable.<{{{datatypeWithEnum}}}>of({{{defaultValue}}});
+    }
+    try {
+      this.{{name}}.get().add({{name}}Item);
+    } catch (java.util.NoSuchElementException e) {
+      // this can never happen, as we make sure above that the value is present
+    }
+    return this;
+    {{/vendorExtensions.isJacksonOptionalNullable}}
+    {{^vendorExtensions.isJacksonOptionalNullable}}
     {{^required}}
     if (this.{{name}} == null) {
       this.{{name}} = {{{defaultValue}}};
@@ -104,11 +116,24 @@ public class {{classname}} {{#parent}}extends {{{parent}}} {{/parent}}{{#parcela
     {{/required}}
     this.{{name}}.add({{name}}Item);
     return this;
+    {{/vendorExtensions.isJacksonOptionalNullable}}
   }
   {{/isListContainer}}
   {{#isMapContainer}}
 
   public {{classname}} put{{nameInCamelCase}}Item(String key, {{{items.datatypeWithEnum}}} {{name}}Item) {
+    {{#vendorExtensions.isJacksonOptionalNullable}}
+    if (this.{{name}} == null || !this.{{name}}.isPresent()) {
+      this.{{name}} = JsonNullable.<{{{datatypeWithEnum}}}>of({{{defaultValue}}});
+    }
+    try {
+      this.{{name}}.get().put(key, {{name}}Item);
+    } catch (java.util.NoSuchElementException e) {
+      // this can never happen, as we make sure above that the value is present
+    }
+    return this;
+    {{/vendorExtensions.isJacksonOptionalNullable}}
+    {{^vendorExtensions.isJacksonOptionalNullable}}
     {{^required}}
     if (this.{{name}} == null) {
       this.{{name}} = {{{defaultValue}}};
@@ -116,6 +141,7 @@ public class {{classname}} {{#parent}}extends {{{parent}}} {{/parent}}{{#parcela
     {{/required}}
     this.{{name}}.put(key, {{name}}Item);
     return this;
+    {{/vendorExtensions.isJacksonOptionalNullable}}
   }
   {{/isMapContainer}}
 
@@ -147,13 +173,43 @@ public class {{classname}} {{#parent}}extends {{{parent}}} {{/parent}}{{#parcela
 {{#vendorExtensions.extraAnnotation}}
   {{{vendorExtensions.extraAnnotation}}}
 {{/vendorExtensions.extraAnnotation}}
+{{^vendorExtensions.isJacksonOptionalNullable}}{{#jackson}}{{> jackson_annotations}}{{/jackson}}{{/vendorExtensions.isJacksonOptionalNullable}}
   public {{{datatypeWithEnum}}} {{getter}}() {
+    {{#vendorExtensions.isJacksonOptionalNullable}}
+    {{#isReadOnly}}{{! A readonly attribute doesn't have setter => jackson will set null directly if explicitly returned by API, so make sure we have an empty JsonNullable}}
+    if ({{name}} == null) {
+      {{name}} = JsonNullable.<{{{datatypeWithEnum}}}>{{#defaultValue}}of({{{.}}}){{/defaultValue}}{{^defaultValue}}undefined(){{/defaultValue}};
+    }
+    {{/isReadOnly}}
+    return {{name}}.orElse(null);
+    {{/vendorExtensions.isJacksonOptionalNullable}}
+    {{^vendorExtensions.isJacksonOptionalNullable}}
+    return {{name}};
+    {{/vendorExtensions.isJacksonOptionalNullable}}
+  }
+
+  {{#vendorExtensions.isJacksonOptionalNullable}}
+{{> jackson_annotations}}
+  public JsonNullable<{{{datatypeWithEnum}}}> {{getter}}_JsonNullable() {
     return {{name}};
   }
+  {{/vendorExtensions.isJacksonOptionalNullable}}
+
   {{^isReadOnly}}
+  {{#vendorExtensions.isJacksonOptionalNullable}}
+  @JsonProperty(JSON_PROPERTY_{{nameInSnakeCase}})
+  public void {{setter}}_JsonNullable(JsonNullable<{{{datatypeWithEnum}}}> {{name}}) {
+    this.{{name}} = {{name}};
+  }
+  {{/vendorExtensions.isJacksonOptionalNullable}}
 
   public void {{setter}}({{{datatypeWithEnum}}} {{name}}) {
+    {{#vendorExtensions.isJacksonOptionalNullable}}
+    this.{{name}} = JsonNullable.<{{{datatypeWithEnum}}}>of({{name}});
+    {{/vendorExtensions.isJacksonOptionalNullable}}
+    {{^vendorExtensions.isJacksonOptionalNullable}}
     this.{{name}} = {{name}};
+    {{/vendorExtensions.isJacksonOptionalNullable}}
   }
   {{/isReadOnly}}
 

samples/client/petstore/groovy/src/main/groovy/org/openapitools/model/Pet.groovy

@@ -13,7 +13,7 @@ class Pet {
     
     Long id
     
-    Category category = null
+    Category category
     
     String name
     

samples/client/petstore/java/feign/pom.xml

@@ -236,6 +236,11 @@
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-databind</artifactId>
             <version>${jackson-databind-version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.openapitools</groupId>
+            <artifactId>jackson-databind-nullable</artifactId>
+            <version>${jackson-databind-nullable-version}</version>
         </dependency>
             <dependency>
                 <groupId>com.github.joschi.jackson</groupId>
@@ -277,6 +282,7 @@
         <feign-version>9.7.0</feign-version>
         <feign-form-version>2.1.0</feign-form-version>
         <jackson-version>2.9.9</jackson-version>
+        <jackson-databind-nullable-version>0.2.0</jackson-databind-nullable-version>
         <jackson-databind-version>2.9.9</jackson-databind-version>
         <jackson-threetenbp-version>2.6.4</jackson-threetenbp-version>
         <junit-version>4.12</junit-version>

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/ApiClient.java

@@ -10,6 +10,7 @@ import org.threeten.bp.*;
 import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.SerializationFeature;
+import org.openapitools.jackson.nullable.JsonNullableModule;
 import com.fasterxml.jackson.datatype.threetenbp.ThreeTenModule;
 
 import feign.Feign;
@@ -143,6 +144,8 @@ public class ApiClient {
     module.addDeserializer(OffsetDateTime.class, CustomInstantDeserializer.OFFSET_DATE_TIME);
     module.addDeserializer(ZonedDateTime.class, CustomInstantDeserializer.ZONED_DATE_TIME);
     objectMapper.registerModule(module);
+    JsonNullableModule jnm = new JsonNullableModule();
+    objectMapper.registerModule(jnm);
     return objectMapper;
   }
 

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/AdditionalPropertiesAnyType.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -29,10 +30,11 @@ import java.util.Map;
 
 public class AdditionalPropertiesAnyType extends HashMap<String, Object> {
   public static final String JSON_PROPERTY_NAME = "name";
-  @JsonProperty(JSON_PROPERTY_NAME)
   private String name;
 
+
   public AdditionalPropertiesAnyType name(String name) {
+    
     this.name = name;
     return this;
   }
@@ -43,10 +45,15 @@ public class AdditionalPropertiesAnyType extends HashMap<String, Object> {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_NAME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getName() {
     return name;
   }
 
+
+
   public void setName(String name) {
     this.name = name;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/AdditionalPropertiesArray.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -30,10 +31,11 @@ import java.util.Map;
 
 public class AdditionalPropertiesArray extends HashMap<String, List> {
   public static final String JSON_PROPERTY_NAME = "name";
-  @JsonProperty(JSON_PROPERTY_NAME)
   private String name;
 
+
   public AdditionalPropertiesArray name(String name) {
+    
     this.name = name;
     return this;
   }
@@ -44,10 +46,15 @@ public class AdditionalPropertiesArray extends HashMap<String, List> {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_NAME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getName() {
     return name;
   }
 
+
+
   public void setName(String name) {
     this.name = name;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/AdditionalPropertiesBoolean.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -29,10 +30,11 @@ import java.util.Map;
 
 public class AdditionalPropertiesBoolean extends HashMap<String, Boolean> {
   public static final String JSON_PROPERTY_NAME = "name";
-  @JsonProperty(JSON_PROPERTY_NAME)
   private String name;
 
+
   public AdditionalPropertiesBoolean name(String name) {
+    
     this.name = name;
     return this;
   }
@@ -43,10 +45,15 @@ public class AdditionalPropertiesBoolean extends HashMap<String, Boolean> {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_NAME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getName() {
     return name;
   }
 
+
+
   public void setName(String name) {
     this.name = name;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/AdditionalPropertiesClass.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -31,50 +32,41 @@ import java.util.Map;
 
 public class AdditionalPropertiesClass {
   public static final String JSON_PROPERTY_MAP_STRING = "map_string";
-  @JsonProperty(JSON_PROPERTY_MAP_STRING)
   private Map<String, String> mapString = null;
 
   public static final String JSON_PROPERTY_MAP_NUMBER = "map_number";
-  @JsonProperty(JSON_PROPERTY_MAP_NUMBER)
   private Map<String, BigDecimal> mapNumber = null;
 
   public static final String JSON_PROPERTY_MAP_INTEGER = "map_integer";
-  @JsonProperty(JSON_PROPERTY_MAP_INTEGER)
   private Map<String, Integer> mapInteger = null;
 
   public static final String JSON_PROPERTY_MAP_BOOLEAN = "map_boolean";
-  @JsonProperty(JSON_PROPERTY_MAP_BOOLEAN)
   private Map<String, Boolean> mapBoolean = null;
 
   public static final String JSON_PROPERTY_MAP_ARRAY_INTEGER = "map_array_integer";
-  @JsonProperty(JSON_PROPERTY_MAP_ARRAY_INTEGER)
   private Map<String, List<Integer>> mapArrayInteger = null;
 
   public static final String JSON_PROPERTY_MAP_ARRAY_ANYTYPE = "map_array_anytype";
-  @JsonProperty(JSON_PROPERTY_MAP_ARRAY_ANYTYPE)
   private Map<String, List<Object>> mapArrayAnytype = null;
 
   public static final String JSON_PROPERTY_MAP_MAP_STRING = "map_map_string";
-  @JsonProperty(JSON_PROPERTY_MAP_MAP_STRING)
   private Map<String, Map<String, String>> mapMapString = null;
 
   public static final String JSON_PROPERTY_MAP_MAP_ANYTYPE = "map_map_anytype";
-  @JsonProperty(JSON_PROPERTY_MAP_MAP_ANYTYPE)
   private Map<String, Map<String, Object>> mapMapAnytype = null;
 
   public static final String JSON_PROPERTY_ANYTYPE1 = "anytype_1";
-  @JsonProperty(JSON_PROPERTY_ANYTYPE1)
-  private Object anytype1 = null;
+  private Object anytype1;
 
   public static final String JSON_PROPERTY_ANYTYPE2 = "anytype_2";
-  @JsonProperty(JSON_PROPERTY_ANYTYPE2)
-  private Object anytype2 = null;
+  private Object anytype2;
 
   public static final String JSON_PROPERTY_ANYTYPE3 = "anytype_3";
-  @JsonProperty(JSON_PROPERTY_ANYTYPE3)
-  private Object anytype3 = null;
+  private Object anytype3;
+
 
   public AdditionalPropertiesClass mapString(Map<String, String> mapString) {
+    
     this.mapString = mapString;
     return this;
   }
@@ -93,15 +85,22 @@ public class AdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MAP_STRING)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, String> getMapString() {
     return mapString;
   }
 
+
+
   public void setMapString(Map<String, String> mapString) {
     this.mapString = mapString;
   }
 
+
   public AdditionalPropertiesClass mapNumber(Map<String, BigDecimal> mapNumber) {
+    
     this.mapNumber = mapNumber;
     return this;
   }
@@ -120,15 +119,22 @@ public class AdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MAP_NUMBER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, BigDecimal> getMapNumber() {
     return mapNumber;
   }
 
+
+
   public void setMapNumber(Map<String, BigDecimal> mapNumber) {
     this.mapNumber = mapNumber;
   }
 
+
   public AdditionalPropertiesClass mapInteger(Map<String, Integer> mapInteger) {
+    
     this.mapInteger = mapInteger;
     return this;
   }
@@ -147,15 +153,22 @@ public class AdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MAP_INTEGER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, Integer> getMapInteger() {
     return mapInteger;
   }
 
+
+
   public void setMapInteger(Map<String, Integer> mapInteger) {
     this.mapInteger = mapInteger;
   }
 
+
   public AdditionalPropertiesClass mapBoolean(Map<String, Boolean> mapBoolean) {
+    
     this.mapBoolean = mapBoolean;
     return this;
   }
@@ -174,15 +187,22 @@ public class AdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MAP_BOOLEAN)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, Boolean> getMapBoolean() {
     return mapBoolean;
   }
 
+
+
   public void setMapBoolean(Map<String, Boolean> mapBoolean) {
     this.mapBoolean = mapBoolean;
   }
 
+
   public AdditionalPropertiesClass mapArrayInteger(Map<String, List<Integer>> mapArrayInteger) {
+    
     this.mapArrayInteger = mapArrayInteger;
     return this;
   }
@@ -201,15 +221,22 @@ public class AdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MAP_ARRAY_INTEGER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, List<Integer>> getMapArrayInteger() {
     return mapArrayInteger;
   }
 
+
+
   public void setMapArrayInteger(Map<String, List<Integer>> mapArrayInteger) {
     this.mapArrayInteger = mapArrayInteger;
   }
 
+
   public AdditionalPropertiesClass mapArrayAnytype(Map<String, List<Object>> mapArrayAnytype) {
+    
     this.mapArrayAnytype = mapArrayAnytype;
     return this;
   }
@@ -228,15 +255,22 @@ public class AdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MAP_ARRAY_ANYTYPE)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, List<Object>> getMapArrayAnytype() {
     return mapArrayAnytype;
   }
 
+
+
   public void setMapArrayAnytype(Map<String, List<Object>> mapArrayAnytype) {
     this.mapArrayAnytype = mapArrayAnytype;
   }
 
+
   public AdditionalPropertiesClass mapMapString(Map<String, Map<String, String>> mapMapString) {
+    
     this.mapMapString = mapMapString;
     return this;
   }
@@ -255,15 +289,22 @@ public class AdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MAP_MAP_STRING)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, Map<String, String>> getMapMapString() {
     return mapMapString;
   }
 
+
+
   public void setMapMapString(Map<String, Map<String, String>> mapMapString) {
     this.mapMapString = mapMapString;
   }
 
+
   public AdditionalPropertiesClass mapMapAnytype(Map<String, Map<String, Object>> mapMapAnytype) {
+    
     this.mapMapAnytype = mapMapAnytype;
     return this;
   }
@@ -282,15 +323,22 @@ public class AdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MAP_MAP_ANYTYPE)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, Map<String, Object>> getMapMapAnytype() {
     return mapMapAnytype;
   }
 
+
+
   public void setMapMapAnytype(Map<String, Map<String, Object>> mapMapAnytype) {
     this.mapMapAnytype = mapMapAnytype;
   }
 
+
   public AdditionalPropertiesClass anytype1(Object anytype1) {
+    
     this.anytype1 = anytype1;
     return this;
   }
@@ -301,15 +349,22 @@ public class AdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ANYTYPE1)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Object getAnytype1() {
     return anytype1;
   }
 
+
+
   public void setAnytype1(Object anytype1) {
     this.anytype1 = anytype1;
   }
 
+
   public AdditionalPropertiesClass anytype2(Object anytype2) {
+    
     this.anytype2 = anytype2;
     return this;
   }
@@ -320,15 +375,22 @@ public class AdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ANYTYPE2)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Object getAnytype2() {
     return anytype2;
   }
 
+
+
   public void setAnytype2(Object anytype2) {
     this.anytype2 = anytype2;
   }
 
+
   public AdditionalPropertiesClass anytype3(Object anytype3) {
+    
     this.anytype3 = anytype3;
     return this;
   }
@@ -339,10 +401,15 @@ public class AdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ANYTYPE3)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Object getAnytype3() {
     return anytype3;
   }
 
+
+
   public void setAnytype3(Object anytype3) {
     this.anytype3 = anytype3;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/AdditionalPropertiesInteger.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -29,10 +30,11 @@ import java.util.Map;
 
 public class AdditionalPropertiesInteger extends HashMap<String, Integer> {
   public static final String JSON_PROPERTY_NAME = "name";
-  @JsonProperty(JSON_PROPERTY_NAME)
   private String name;
 
+
   public AdditionalPropertiesInteger name(String name) {
+    
     this.name = name;
     return this;
   }
@@ -43,10 +45,15 @@ public class AdditionalPropertiesInteger extends HashMap<String, Integer> {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_NAME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getName() {
     return name;
   }
 
+
+
   public void setName(String name) {
     this.name = name;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/AdditionalPropertiesNumber.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -30,10 +31,11 @@ import java.util.Map;
 
 public class AdditionalPropertiesNumber extends HashMap<String, BigDecimal> {
   public static final String JSON_PROPERTY_NAME = "name";
-  @JsonProperty(JSON_PROPERTY_NAME)
   private String name;
 
+
   public AdditionalPropertiesNumber name(String name) {
+    
     this.name = name;
     return this;
   }
@@ -44,10 +46,15 @@ public class AdditionalPropertiesNumber extends HashMap<String, BigDecimal> {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_NAME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getName() {
     return name;
   }
 
+
+
   public void setName(String name) {
     this.name = name;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/AdditionalPropertiesObject.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -29,10 +30,11 @@ import java.util.Map;
 
 public class AdditionalPropertiesObject extends HashMap<String, Map> {
   public static final String JSON_PROPERTY_NAME = "name";
-  @JsonProperty(JSON_PROPERTY_NAME)
   private String name;
 
+
   public AdditionalPropertiesObject name(String name) {
+    
     this.name = name;
     return this;
   }
@@ -43,10 +45,15 @@ public class AdditionalPropertiesObject extends HashMap<String, Map> {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_NAME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getName() {
     return name;
   }
 
+
+
   public void setName(String name) {
     this.name = name;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/AdditionalPropertiesString.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -29,10 +30,11 @@ import java.util.Map;
 
 public class AdditionalPropertiesString extends HashMap<String, String> {
   public static final String JSON_PROPERTY_NAME = "name";
-  @JsonProperty(JSON_PROPERTY_NAME)
   private String name;
 
+
   public AdditionalPropertiesString name(String name) {
+    
     this.name = name;
     return this;
   }
@@ -43,10 +45,15 @@ public class AdditionalPropertiesString extends HashMap<String, String> {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_NAME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getName() {
     return name;
   }
 
+
+
   public void setName(String name) {
     this.name = name;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/Animal.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonSubTypes;
@@ -35,14 +36,14 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class Animal {
   public static final String JSON_PROPERTY_CLASS_NAME = "className";
-  @JsonProperty(JSON_PROPERTY_CLASS_NAME)
   private String className;
 
   public static final String JSON_PROPERTY_COLOR = "color";
-  @JsonProperty(JSON_PROPERTY_COLOR)
   private String color = "red";
 
+
   public Animal className(String className) {
+    
     this.className = className;
     return this;
   }
@@ -52,15 +53,22 @@ public class Animal {
    * @return className
   **/
   @ApiModelProperty(required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_CLASS_NAME)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public String getClassName() {
     return className;
   }
 
+
+
   public void setClassName(String className) {
     this.className = className;
   }
 
+
   public Animal color(String color) {
+    
     this.color = color;
     return this;
   }
@@ -71,10 +79,15 @@ public class Animal {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_COLOR)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getColor() {
     return color;
   }
 
+
+
   public void setColor(String color) {
     this.color = color;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/ArrayOfArrayOfNumberOnly.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -30,10 +31,11 @@ import java.util.List;
 
 public class ArrayOfArrayOfNumberOnly {
   public static final String JSON_PROPERTY_ARRAY_ARRAY_NUMBER = "ArrayArrayNumber";
-  @JsonProperty(JSON_PROPERTY_ARRAY_ARRAY_NUMBER)
   private List<List<BigDecimal>> arrayArrayNumber = null;
 
+
   public ArrayOfArrayOfNumberOnly arrayArrayNumber(List<List<BigDecimal>> arrayArrayNumber) {
+    
     this.arrayArrayNumber = arrayArrayNumber;
     return this;
   }
@@ -52,10 +54,15 @@ public class ArrayOfArrayOfNumberOnly {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ARRAY_ARRAY_NUMBER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<List<BigDecimal>> getArrayArrayNumber() {
     return arrayArrayNumber;
   }
 
+
+
   public void setArrayArrayNumber(List<List<BigDecimal>> arrayArrayNumber) {
     this.arrayArrayNumber = arrayArrayNumber;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/ArrayOfNumberOnly.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -30,10 +31,11 @@ import java.util.List;
 
 public class ArrayOfNumberOnly {
   public static final String JSON_PROPERTY_ARRAY_NUMBER = "ArrayNumber";
-  @JsonProperty(JSON_PROPERTY_ARRAY_NUMBER)
   private List<BigDecimal> arrayNumber = null;
 
+
   public ArrayOfNumberOnly arrayNumber(List<BigDecimal> arrayNumber) {
+    
     this.arrayNumber = arrayNumber;
     return this;
   }
@@ -52,10 +54,15 @@ public class ArrayOfNumberOnly {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ARRAY_NUMBER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<BigDecimal> getArrayNumber() {
     return arrayNumber;
   }
 
+
+
   public void setArrayNumber(List<BigDecimal> arrayNumber) {
     this.arrayNumber = arrayNumber;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/ArrayTest.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -30,18 +31,17 @@ import org.openapitools.client.model.ReadOnlyFirst;
 
 public class ArrayTest {
   public static final String JSON_PROPERTY_ARRAY_OF_STRING = "array_of_string";
-  @JsonProperty(JSON_PROPERTY_ARRAY_OF_STRING)
   private List<String> arrayOfString = null;
 
   public static final String JSON_PROPERTY_ARRAY_ARRAY_OF_INTEGER = "array_array_of_integer";
-  @JsonProperty(JSON_PROPERTY_ARRAY_ARRAY_OF_INTEGER)
   private List<List<Long>> arrayArrayOfInteger = null;
 
   public static final String JSON_PROPERTY_ARRAY_ARRAY_OF_MODEL = "array_array_of_model";
-  @JsonProperty(JSON_PROPERTY_ARRAY_ARRAY_OF_MODEL)
   private List<List<ReadOnlyFirst>> arrayArrayOfModel = null;
 
+
   public ArrayTest arrayOfString(List<String> arrayOfString) {
+    
     this.arrayOfString = arrayOfString;
     return this;
   }
@@ -60,15 +60,22 @@ public class ArrayTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ARRAY_OF_STRING)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<String> getArrayOfString() {
     return arrayOfString;
   }
 
+
+
   public void setArrayOfString(List<String> arrayOfString) {
     this.arrayOfString = arrayOfString;
   }
 
+
   public ArrayTest arrayArrayOfInteger(List<List<Long>> arrayArrayOfInteger) {
+    
     this.arrayArrayOfInteger = arrayArrayOfInteger;
     return this;
   }
@@ -87,15 +94,22 @@ public class ArrayTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ARRAY_ARRAY_OF_INTEGER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<List<Long>> getArrayArrayOfInteger() {
     return arrayArrayOfInteger;
   }
 
+
+
   public void setArrayArrayOfInteger(List<List<Long>> arrayArrayOfInteger) {
     this.arrayArrayOfInteger = arrayArrayOfInteger;
   }
 
+
   public ArrayTest arrayArrayOfModel(List<List<ReadOnlyFirst>> arrayArrayOfModel) {
+    
     this.arrayArrayOfModel = arrayArrayOfModel;
     return this;
   }
@@ -114,10 +128,15 @@ public class ArrayTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ARRAY_ARRAY_OF_MODEL)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<List<ReadOnlyFirst>> getArrayArrayOfModel() {
     return arrayArrayOfModel;
   }
 
+
+
   public void setArrayArrayOfModel(List<List<ReadOnlyFirst>> arrayArrayOfModel) {
     this.arrayArrayOfModel = arrayArrayOfModel;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/Capitalization.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -27,30 +28,26 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class Capitalization {
   public static final String JSON_PROPERTY_SMALL_CAMEL = "smallCamel";
-  @JsonProperty(JSON_PROPERTY_SMALL_CAMEL)
   private String smallCamel;
 
   public static final String JSON_PROPERTY_CAPITAL_CAMEL = "CapitalCamel";
-  @JsonProperty(JSON_PROPERTY_CAPITAL_CAMEL)
   private String capitalCamel;
 
   public static final String JSON_PROPERTY_SMALL_SNAKE = "small_Snake";
-  @JsonProperty(JSON_PROPERTY_SMALL_SNAKE)
   private String smallSnake;
 
   public static final String JSON_PROPERTY_CAPITAL_SNAKE = "Capital_Snake";
-  @JsonProperty(JSON_PROPERTY_CAPITAL_SNAKE)
   private String capitalSnake;
 
   public static final String JSON_PROPERTY_SC_A_E_T_H_FLOW_POINTS = "SCA_ETH_Flow_Points";
-  @JsonProperty(JSON_PROPERTY_SC_A_E_T_H_FLOW_POINTS)
   private String scAETHFlowPoints;
 
   public static final String JSON_PROPERTY_A_T_T_N_A_M_E = "ATT_NAME";
-  @JsonProperty(JSON_PROPERTY_A_T_T_N_A_M_E)
   private String ATT_NAME;
 
+
   public Capitalization smallCamel(String smallCamel) {
+    
     this.smallCamel = smallCamel;
     return this;
   }
@@ -61,15 +58,22 @@ public class Capitalization {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_SMALL_CAMEL)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getSmallCamel() {
     return smallCamel;
   }
 
+
+
   public void setSmallCamel(String smallCamel) {
     this.smallCamel = smallCamel;
   }
 
+
   public Capitalization capitalCamel(String capitalCamel) {
+    
     this.capitalCamel = capitalCamel;
     return this;
   }
@@ -80,15 +84,22 @@ public class Capitalization {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_CAPITAL_CAMEL)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getCapitalCamel() {
     return capitalCamel;
   }
 
+
+
   public void setCapitalCamel(String capitalCamel) {
     this.capitalCamel = capitalCamel;
   }
 
+
   public Capitalization smallSnake(String smallSnake) {
+    
     this.smallSnake = smallSnake;
     return this;
   }
@@ -99,15 +110,22 @@ public class Capitalization {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_SMALL_SNAKE)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getSmallSnake() {
     return smallSnake;
   }
 
+
+
   public void setSmallSnake(String smallSnake) {
     this.smallSnake = smallSnake;
   }
 
+
   public Capitalization capitalSnake(String capitalSnake) {
+    
     this.capitalSnake = capitalSnake;
     return this;
   }
@@ -118,15 +136,22 @@ public class Capitalization {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_CAPITAL_SNAKE)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getCapitalSnake() {
     return capitalSnake;
   }
 
+
+
   public void setCapitalSnake(String capitalSnake) {
     this.capitalSnake = capitalSnake;
   }
 
+
   public Capitalization scAETHFlowPoints(String scAETHFlowPoints) {
+    
     this.scAETHFlowPoints = scAETHFlowPoints;
     return this;
   }
@@ -137,15 +162,22 @@ public class Capitalization {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_SC_A_E_T_H_FLOW_POINTS)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getScAETHFlowPoints() {
     return scAETHFlowPoints;
   }
 
+
+
   public void setScAETHFlowPoints(String scAETHFlowPoints) {
     this.scAETHFlowPoints = scAETHFlowPoints;
   }
 
+
   public Capitalization ATT_NAME(String ATT_NAME) {
+    
     this.ATT_NAME = ATT_NAME;
     return this;
   }
@@ -156,10 +188,15 @@ public class Capitalization {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "Name of the pet ")
+  @JsonProperty(JSON_PROPERTY_A_T_T_N_A_M_E)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getATTNAME() {
     return ATT_NAME;
   }
 
+
+
   public void setATTNAME(String ATT_NAME) {
     this.ATT_NAME = ATT_NAME;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/Cat.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -29,10 +30,11 @@ import org.openapitools.client.model.CatAllOf;
 
 public class Cat extends Animal {
   public static final String JSON_PROPERTY_DECLAWED = "declawed";
-  @JsonProperty(JSON_PROPERTY_DECLAWED)
   private Boolean declawed;
 
+
   public Cat declawed(Boolean declawed) {
+    
     this.declawed = declawed;
     return this;
   }
@@ -43,10 +45,15 @@ public class Cat extends Animal {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_DECLAWED)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Boolean isDeclawed() {
     return declawed;
   }
 
+
+
   public void setDeclawed(Boolean declawed) {
     this.declawed = declawed;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/CatAllOf.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -27,10 +28,11 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class CatAllOf {
   public static final String JSON_PROPERTY_DECLAWED = "declawed";
-  @JsonProperty(JSON_PROPERTY_DECLAWED)
   private Boolean declawed;
 
+
   public CatAllOf declawed(Boolean declawed) {
+    
     this.declawed = declawed;
     return this;
   }
@@ -41,10 +43,15 @@ public class CatAllOf {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_DECLAWED)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Boolean isDeclawed() {
     return declawed;
   }
 
+
+
   public void setDeclawed(Boolean declawed) {
     this.declawed = declawed;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/Category.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -27,14 +28,14 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class Category {
   public static final String JSON_PROPERTY_ID = "id";
-  @JsonProperty(JSON_PROPERTY_ID)
   private Long id;
 
   public static final String JSON_PROPERTY_NAME = "name";
-  @JsonProperty(JSON_PROPERTY_NAME)
   private String name = "default-name";
 
+
   public Category id(Long id) {
+    
     this.id = id;
     return this;
   }
@@ -45,15 +46,22 @@ public class Category {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ID)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Long getId() {
     return id;
   }
 
+
+
   public void setId(Long id) {
     this.id = id;
   }
 
+
   public Category name(String name) {
+    
     this.name = name;
     return this;
   }
@@ -63,10 +71,15 @@ public class Category {
    * @return name
   **/
   @ApiModelProperty(required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_NAME)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public String getName() {
     return name;
   }
 
+
+
   public void setName(String name) {
     this.name = name;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/ClassModel.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -28,10 +29,11 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class ClassModel {
   public static final String JSON_PROPERTY_PROPERTY_CLASS = "_class";
-  @JsonProperty(JSON_PROPERTY_PROPERTY_CLASS)
   private String propertyClass;
 
+
   public ClassModel propertyClass(String propertyClass) {
+    
     this.propertyClass = propertyClass;
     return this;
   }
@@ -42,10 +44,15 @@ public class ClassModel {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_PROPERTY_CLASS)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getPropertyClass() {
     return propertyClass;
   }
 
+
+
   public void setPropertyClass(String propertyClass) {
     this.propertyClass = propertyClass;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/Client.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -27,10 +28,11 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class Client {
   public static final String JSON_PROPERTY_CLIENT = "client";
-  @JsonProperty(JSON_PROPERTY_CLIENT)
   private String client;
 
+
   public Client client(String client) {
+    
     this.client = client;
     return this;
   }
@@ -41,10 +43,15 @@ public class Client {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_CLIENT)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getClient() {
     return client;
   }
 
+
+
   public void setClient(String client) {
     this.client = client;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/Dog.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -29,10 +30,11 @@ import org.openapitools.client.model.DogAllOf;
 
 public class Dog extends Animal {
   public static final String JSON_PROPERTY_BREED = "breed";
-  @JsonProperty(JSON_PROPERTY_BREED)
   private String breed;
 
+
   public Dog breed(String breed) {
+    
     this.breed = breed;
     return this;
   }
@@ -43,10 +45,15 @@ public class Dog extends Animal {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_BREED)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getBreed() {
     return breed;
   }
 
+
+
   public void setBreed(String breed) {
     this.breed = breed;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/DogAllOf.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -27,10 +28,11 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class DogAllOf {
   public static final String JSON_PROPERTY_BREED = "breed";
-  @JsonProperty(JSON_PROPERTY_BREED)
   private String breed;
 
+
   public DogAllOf breed(String breed) {
+    
     this.breed = breed;
     return this;
   }
@@ -41,10 +43,15 @@ public class DogAllOf {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_BREED)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getBreed() {
     return breed;
   }
 
+
+
   public void setBreed(String breed) {
     this.breed = breed;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/EnumArrays.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -64,7 +65,6 @@ public class EnumArrays {
   }
 
   public static final String JSON_PROPERTY_JUST_SYMBOL = "just_symbol";
-  @JsonProperty(JSON_PROPERTY_JUST_SYMBOL)
   private JustSymbolEnum justSymbol;
 
   /**
@@ -103,10 +103,11 @@ public class EnumArrays {
   }
 
   public static final String JSON_PROPERTY_ARRAY_ENUM = "array_enum";
-  @JsonProperty(JSON_PROPERTY_ARRAY_ENUM)
   private List<ArrayEnumEnum> arrayEnum = null;
 
+
   public EnumArrays justSymbol(JustSymbolEnum justSymbol) {
+    
     this.justSymbol = justSymbol;
     return this;
   }
@@ -117,15 +118,22 @@ public class EnumArrays {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_JUST_SYMBOL)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public JustSymbolEnum getJustSymbol() {
     return justSymbol;
   }
 
+
+
   public void setJustSymbol(JustSymbolEnum justSymbol) {
     this.justSymbol = justSymbol;
   }
 
+
   public EnumArrays arrayEnum(List<ArrayEnumEnum> arrayEnum) {
+    
     this.arrayEnum = arrayEnum;
     return this;
   }
@@ -144,10 +152,15 @@ public class EnumArrays {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ARRAY_ENUM)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<ArrayEnumEnum> getArrayEnum() {
     return arrayEnum;
   }
 
+
+
   public void setArrayEnum(List<ArrayEnumEnum> arrayEnum) {
     this.arrayEnum = arrayEnum;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/EnumTest.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -65,7 +66,6 @@ public class EnumTest {
   }
 
   public static final String JSON_PROPERTY_ENUM_STRING = "enum_string";
-  @JsonProperty(JSON_PROPERTY_ENUM_STRING)
   private EnumStringEnum enumString;
 
   /**
@@ -106,7 +106,6 @@ public class EnumTest {
   }
 
   public static final String JSON_PROPERTY_ENUM_STRING_REQUIRED = "enum_string_required";
-  @JsonProperty(JSON_PROPERTY_ENUM_STRING_REQUIRED)
   private EnumStringRequiredEnum enumStringRequired;
 
   /**
@@ -145,7 +144,6 @@ public class EnumTest {
   }
 
   public static final String JSON_PROPERTY_ENUM_INTEGER = "enum_integer";
-  @JsonProperty(JSON_PROPERTY_ENUM_INTEGER)
   private EnumIntegerEnum enumInteger;
 
   /**
@@ -184,14 +182,14 @@ public class EnumTest {
   }
 
   public static final String JSON_PROPERTY_ENUM_NUMBER = "enum_number";
-  @JsonProperty(JSON_PROPERTY_ENUM_NUMBER)
   private EnumNumberEnum enumNumber;
 
   public static final String JSON_PROPERTY_OUTER_ENUM = "outerEnum";
-  @JsonProperty(JSON_PROPERTY_OUTER_ENUM)
   private OuterEnum outerEnum;
 
+
   public EnumTest enumString(EnumStringEnum enumString) {
+    
     this.enumString = enumString;
     return this;
   }
@@ -202,15 +200,22 @@ public class EnumTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ENUM_STRING)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public EnumStringEnum getEnumString() {
     return enumString;
   }
 
+
+
   public void setEnumString(EnumStringEnum enumString) {
     this.enumString = enumString;
   }
 
+
   public EnumTest enumStringRequired(EnumStringRequiredEnum enumStringRequired) {
+    
     this.enumStringRequired = enumStringRequired;
     return this;
   }
@@ -220,15 +225,22 @@ public class EnumTest {
    * @return enumStringRequired
   **/
   @ApiModelProperty(required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_ENUM_STRING_REQUIRED)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public EnumStringRequiredEnum getEnumStringRequired() {
     return enumStringRequired;
   }
 
+
+
   public void setEnumStringRequired(EnumStringRequiredEnum enumStringRequired) {
     this.enumStringRequired = enumStringRequired;
   }
 
+
   public EnumTest enumInteger(EnumIntegerEnum enumInteger) {
+    
     this.enumInteger = enumInteger;
     return this;
   }
@@ -239,15 +251,22 @@ public class EnumTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ENUM_INTEGER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public EnumIntegerEnum getEnumInteger() {
     return enumInteger;
   }
 
+
+
   public void setEnumInteger(EnumIntegerEnum enumInteger) {
     this.enumInteger = enumInteger;
   }
 
+
   public EnumTest enumNumber(EnumNumberEnum enumNumber) {
+    
     this.enumNumber = enumNumber;
     return this;
   }
@@ -258,15 +277,22 @@ public class EnumTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ENUM_NUMBER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public EnumNumberEnum getEnumNumber() {
     return enumNumber;
   }
 
+
+
   public void setEnumNumber(EnumNumberEnum enumNumber) {
     this.enumNumber = enumNumber;
   }
 
+
   public EnumTest outerEnum(OuterEnum outerEnum) {
+    
     this.outerEnum = outerEnum;
     return this;
   }
@@ -277,10 +303,15 @@ public class EnumTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_OUTER_ENUM)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public OuterEnum getOuterEnum() {
     return outerEnum;
   }
 
+
+
   public void setOuterEnum(OuterEnum outerEnum) {
     this.outerEnum = outerEnum;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/FileSchemaTestClass.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -29,14 +30,14 @@ import java.util.List;
 
 public class FileSchemaTestClass {
   public static final String JSON_PROPERTY_FILE = "file";
-  @JsonProperty(JSON_PROPERTY_FILE)
-  private java.io.File file = null;
+  private java.io.File file;
 
   public static final String JSON_PROPERTY_FILES = "files";
-  @JsonProperty(JSON_PROPERTY_FILES)
   private List<java.io.File> files = null;
 
+
   public FileSchemaTestClass file(java.io.File file) {
+    
     this.file = file;
     return this;
   }
@@ -47,15 +48,22 @@ public class FileSchemaTestClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_FILE)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public java.io.File getFile() {
     return file;
   }
 
+
+
   public void setFile(java.io.File file) {
     this.file = file;
   }
 
+
   public FileSchemaTestClass files(List<java.io.File> files) {
+    
     this.files = files;
     return this;
   }
@@ -74,10 +82,15 @@ public class FileSchemaTestClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_FILES)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<java.io.File> getFiles() {
     return files;
   }
 
+
+
   public void setFiles(List<java.io.File> files) {
     this.files = files;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/FormatTest.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -32,58 +33,47 @@ import org.threeten.bp.OffsetDateTime;
 
 public class FormatTest {
   public static final String JSON_PROPERTY_INTEGER = "integer";
-  @JsonProperty(JSON_PROPERTY_INTEGER)
   private Integer integer;
 
   public static final String JSON_PROPERTY_INT32 = "int32";
-  @JsonProperty(JSON_PROPERTY_INT32)
   private Integer int32;
 
   public static final String JSON_PROPERTY_INT64 = "int64";
-  @JsonProperty(JSON_PROPERTY_INT64)
   private Long int64;
 
   public static final String JSON_PROPERTY_NUMBER = "number";
-  @JsonProperty(JSON_PROPERTY_NUMBER)
   private BigDecimal number;
 
   public static final String JSON_PROPERTY_FLOAT = "float";
-  @JsonProperty(JSON_PROPERTY_FLOAT)
   private Float _float;
 
   public static final String JSON_PROPERTY_DOUBLE = "double";
-  @JsonProperty(JSON_PROPERTY_DOUBLE)
   private Double _double;
 
   public static final String JSON_PROPERTY_STRING = "string";
-  @JsonProperty(JSON_PROPERTY_STRING)
   private String string;
 
   public static final String JSON_PROPERTY_BYTE = "byte";
-  @JsonProperty(JSON_PROPERTY_BYTE)
   private byte[] _byte;
 
   public static final String JSON_PROPERTY_BINARY = "binary";
-  @JsonProperty(JSON_PROPERTY_BINARY)
   private File binary;
 
   public static final String JSON_PROPERTY_DATE = "date";
-  @JsonProperty(JSON_PROPERTY_DATE)
   private LocalDate date;
 
   public static final String JSON_PROPERTY_DATE_TIME = "dateTime";
-  @JsonProperty(JSON_PROPERTY_DATE_TIME)
   private OffsetDateTime dateTime;
 
   public static final String JSON_PROPERTY_UUID = "uuid";
-  @JsonProperty(JSON_PROPERTY_UUID)
   private UUID uuid;
 
   public static final String JSON_PROPERTY_PASSWORD = "password";
-  @JsonProperty(JSON_PROPERTY_PASSWORD)
   private String password;
 
+
   public FormatTest integer(Integer integer) {
+    
     this.integer = integer;
     return this;
   }
@@ -96,15 +86,22 @@ public class FormatTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_INTEGER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Integer getInteger() {
     return integer;
   }
 
+
+
   public void setInteger(Integer integer) {
     this.integer = integer;
   }
 
+
   public FormatTest int32(Integer int32) {
+    
     this.int32 = int32;
     return this;
   }
@@ -117,15 +114,22 @@ public class FormatTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_INT32)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Integer getInt32() {
     return int32;
   }
 
+
+
   public void setInt32(Integer int32) {
     this.int32 = int32;
   }
 
+
   public FormatTest int64(Long int64) {
+    
     this.int64 = int64;
     return this;
   }
@@ -136,15 +140,22 @@ public class FormatTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_INT64)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Long getInt64() {
     return int64;
   }
 
+
+
   public void setInt64(Long int64) {
     this.int64 = int64;
   }
 
+
   public FormatTest number(BigDecimal number) {
+    
     this.number = number;
     return this;
   }
@@ -156,15 +167,22 @@ public class FormatTest {
    * @return number
   **/
   @ApiModelProperty(required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_NUMBER)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public BigDecimal getNumber() {
     return number;
   }
 
+
+
   public void setNumber(BigDecimal number) {
     this.number = number;
   }
 
+
   public FormatTest _float(Float _float) {
+    
     this._float = _float;
     return this;
   }
@@ -177,15 +195,22 @@ public class FormatTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_FLOAT)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Float getFloat() {
     return _float;
   }
 
+
+
   public void setFloat(Float _float) {
     this._float = _float;
   }
 
+
   public FormatTest _double(Double _double) {
+    
     this._double = _double;
     return this;
   }
@@ -198,15 +223,22 @@ public class FormatTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_DOUBLE)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Double getDouble() {
     return _double;
   }
 
+
+
   public void setDouble(Double _double) {
     this._double = _double;
   }
 
+
   public FormatTest string(String string) {
+    
     this.string = string;
     return this;
   }
@@ -217,15 +249,22 @@ public class FormatTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_STRING)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getString() {
     return string;
   }
 
+
+
   public void setString(String string) {
     this.string = string;
   }
 
+
   public FormatTest _byte(byte[] _byte) {
+    
     this._byte = _byte;
     return this;
   }
@@ -235,15 +274,22 @@ public class FormatTest {
    * @return _byte
   **/
   @ApiModelProperty(required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_BYTE)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public byte[] getByte() {
     return _byte;
   }
 
+
+
   public void setByte(byte[] _byte) {
     this._byte = _byte;
   }
 
+
   public FormatTest binary(File binary) {
+    
     this.binary = binary;
     return this;
   }
@@ -254,15 +300,22 @@ public class FormatTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_BINARY)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public File getBinary() {
     return binary;
   }
 
+
+
   public void setBinary(File binary) {
     this.binary = binary;
   }
 
+
   public FormatTest date(LocalDate date) {
+    
     this.date = date;
     return this;
   }
@@ -272,15 +325,22 @@ public class FormatTest {
    * @return date
   **/
   @ApiModelProperty(required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_DATE)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public LocalDate getDate() {
     return date;
   }
 
+
+
   public void setDate(LocalDate date) {
     this.date = date;
   }
 
+
   public FormatTest dateTime(OffsetDateTime dateTime) {
+    
     this.dateTime = dateTime;
     return this;
   }
@@ -291,15 +351,22 @@ public class FormatTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_DATE_TIME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public OffsetDateTime getDateTime() {
     return dateTime;
   }
 
+
+
   public void setDateTime(OffsetDateTime dateTime) {
     this.dateTime = dateTime;
   }
 
+
   public FormatTest uuid(UUID uuid) {
+    
     this.uuid = uuid;
     return this;
   }
@@ -310,15 +377,22 @@ public class FormatTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(example = "72f98069-206d-4f12-9f12-3d1e525a8e84", value = "")
+  @JsonProperty(JSON_PROPERTY_UUID)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public UUID getUuid() {
     return uuid;
   }
 
+
+
   public void setUuid(UUID uuid) {
     this.uuid = uuid;
   }
 
+
   public FormatTest password(String password) {
+    
     this.password = password;
     return this;
   }
@@ -328,10 +402,15 @@ public class FormatTest {
    * @return password
   **/
   @ApiModelProperty(required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_PASSWORD)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public String getPassword() {
     return password;
   }
 
+
+
   public void setPassword(String password) {
     this.password = password;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/HasOnlyReadOnly.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -27,34 +28,44 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class HasOnlyReadOnly {
   public static final String JSON_PROPERTY_BAR = "bar";
-  @JsonProperty(JSON_PROPERTY_BAR)
   private String bar;
 
   public static final String JSON_PROPERTY_FOO = "foo";
-  @JsonProperty(JSON_PROPERTY_FOO)
   private String foo;
 
+
    /**
    * Get bar
    * @return bar
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_BAR)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getBar() {
     return bar;
   }
 
+
+
+
    /**
    * Get foo
    * @return foo
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_FOO)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getFoo() {
     return foo;
   }
 
 
+
+
   @Override
   public boolean equals(java.lang.Object o) {
     if (this == o) {

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/MapTest.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -30,7 +31,6 @@ import java.util.Map;
 
 public class MapTest {
   public static final String JSON_PROPERTY_MAP_MAP_OF_STRING = "map_map_of_string";
-  @JsonProperty(JSON_PROPERTY_MAP_MAP_OF_STRING)
   private Map<String, Map<String, String>> mapMapOfString = null;
 
   /**
@@ -69,18 +69,17 @@ public class MapTest {
   }
 
   public static final String JSON_PROPERTY_MAP_OF_ENUM_STRING = "map_of_enum_string";
-  @JsonProperty(JSON_PROPERTY_MAP_OF_ENUM_STRING)
   private Map<String, InnerEnum> mapOfEnumString = null;
 
   public static final String JSON_PROPERTY_DIRECT_MAP = "direct_map";
-  @JsonProperty(JSON_PROPERTY_DIRECT_MAP)
   private Map<String, Boolean> directMap = null;
 
   public static final String JSON_PROPERTY_INDIRECT_MAP = "indirect_map";
-  @JsonProperty(JSON_PROPERTY_INDIRECT_MAP)
   private Map<String, Boolean> indirectMap = null;
 
+
   public MapTest mapMapOfString(Map<String, Map<String, String>> mapMapOfString) {
+    
     this.mapMapOfString = mapMapOfString;
     return this;
   }
@@ -99,15 +98,22 @@ public class MapTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MAP_MAP_OF_STRING)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, Map<String, String>> getMapMapOfString() {
     return mapMapOfString;
   }
 
+
+
   public void setMapMapOfString(Map<String, Map<String, String>> mapMapOfString) {
     this.mapMapOfString = mapMapOfString;
   }
 
+
   public MapTest mapOfEnumString(Map<String, InnerEnum> mapOfEnumString) {
+    
     this.mapOfEnumString = mapOfEnumString;
     return this;
   }
@@ -126,15 +132,22 @@ public class MapTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MAP_OF_ENUM_STRING)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, InnerEnum> getMapOfEnumString() {
     return mapOfEnumString;
   }
 
+
+
   public void setMapOfEnumString(Map<String, InnerEnum> mapOfEnumString) {
     this.mapOfEnumString = mapOfEnumString;
   }
 
+
   public MapTest directMap(Map<String, Boolean> directMap) {
+    
     this.directMap = directMap;
     return this;
   }
@@ -153,15 +166,22 @@ public class MapTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_DIRECT_MAP)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, Boolean> getDirectMap() {
     return directMap;
   }
 
+
+
   public void setDirectMap(Map<String, Boolean> directMap) {
     this.directMap = directMap;
   }
 
+
   public MapTest indirectMap(Map<String, Boolean> indirectMap) {
+    
     this.indirectMap = indirectMap;
     return this;
   }
@@ -180,10 +200,15 @@ public class MapTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_INDIRECT_MAP)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, Boolean> getIndirectMap() {
     return indirectMap;
   }
 
+
+
   public void setIndirectMap(Map<String, Boolean> indirectMap) {
     this.indirectMap = indirectMap;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/MixedPropertiesAndAdditionalPropertiesClass.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -33,18 +34,17 @@ import org.threeten.bp.OffsetDateTime;
 
 public class MixedPropertiesAndAdditionalPropertiesClass {
   public static final String JSON_PROPERTY_UUID = "uuid";
-  @JsonProperty(JSON_PROPERTY_UUID)
   private UUID uuid;
 
   public static final String JSON_PROPERTY_DATE_TIME = "dateTime";
-  @JsonProperty(JSON_PROPERTY_DATE_TIME)
   private OffsetDateTime dateTime;
 
   public static final String JSON_PROPERTY_MAP = "map";
-  @JsonProperty(JSON_PROPERTY_MAP)
   private Map<String, Animal> map = null;
 
+
   public MixedPropertiesAndAdditionalPropertiesClass uuid(UUID uuid) {
+    
     this.uuid = uuid;
     return this;
   }
@@ -55,15 +55,22 @@ public class MixedPropertiesAndAdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_UUID)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public UUID getUuid() {
     return uuid;
   }
 
+
+
   public void setUuid(UUID uuid) {
     this.uuid = uuid;
   }
 
+
   public MixedPropertiesAndAdditionalPropertiesClass dateTime(OffsetDateTime dateTime) {
+    
     this.dateTime = dateTime;
     return this;
   }
@@ -74,15 +81,22 @@ public class MixedPropertiesAndAdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_DATE_TIME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public OffsetDateTime getDateTime() {
     return dateTime;
   }
 
+
+
   public void setDateTime(OffsetDateTime dateTime) {
     this.dateTime = dateTime;
   }
 
+
   public MixedPropertiesAndAdditionalPropertiesClass map(Map<String, Animal> map) {
+    
     this.map = map;
     return this;
   }
@@ -101,10 +115,15 @@ public class MixedPropertiesAndAdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MAP)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, Animal> getMap() {
     return map;
   }
 
+
+
   public void setMap(Map<String, Animal> map) {
     this.map = map;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/Model200Response.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -28,14 +29,14 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class Model200Response {
   public static final String JSON_PROPERTY_NAME = "name";
-  @JsonProperty(JSON_PROPERTY_NAME)
   private Integer name;
 
   public static final String JSON_PROPERTY_PROPERTY_CLASS = "class";
-  @JsonProperty(JSON_PROPERTY_PROPERTY_CLASS)
   private String propertyClass;
 
+
   public Model200Response name(Integer name) {
+    
     this.name = name;
     return this;
   }
@@ -46,15 +47,22 @@ public class Model200Response {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_NAME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Integer getName() {
     return name;
   }
 
+
+
   public void setName(Integer name) {
     this.name = name;
   }
 
+
   public Model200Response propertyClass(String propertyClass) {
+    
     this.propertyClass = propertyClass;
     return this;
   }
@@ -65,10 +73,15 @@ public class Model200Response {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_PROPERTY_CLASS)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getPropertyClass() {
     return propertyClass;
   }
 
+
+
   public void setPropertyClass(String propertyClass) {
     this.propertyClass = propertyClass;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/ModelApiResponse.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -27,18 +28,17 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class ModelApiResponse {
   public static final String JSON_PROPERTY_CODE = "code";
-  @JsonProperty(JSON_PROPERTY_CODE)
   private Integer code;
 
   public static final String JSON_PROPERTY_TYPE = "type";
-  @JsonProperty(JSON_PROPERTY_TYPE)
   private String type;
 
   public static final String JSON_PROPERTY_MESSAGE = "message";
-  @JsonProperty(JSON_PROPERTY_MESSAGE)
   private String message;
 
+
   public ModelApiResponse code(Integer code) {
+    
     this.code = code;
     return this;
   }
@@ -49,15 +49,22 @@ public class ModelApiResponse {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_CODE)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Integer getCode() {
     return code;
   }
 
+
+
   public void setCode(Integer code) {
     this.code = code;
   }
 
+
   public ModelApiResponse type(String type) {
+    
     this.type = type;
     return this;
   }
@@ -68,15 +75,22 @@ public class ModelApiResponse {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_TYPE)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getType() {
     return type;
   }
 
+
+
   public void setType(String type) {
     this.type = type;
   }
 
+
   public ModelApiResponse message(String message) {
+    
     this.message = message;
     return this;
   }
@@ -87,10 +101,15 @@ public class ModelApiResponse {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MESSAGE)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getMessage() {
     return message;
   }
 
+
+
   public void setMessage(String message) {
     this.message = message;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/ModelReturn.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -28,10 +29,11 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class ModelReturn {
   public static final String JSON_PROPERTY_RETURN = "return";
-  @JsonProperty(JSON_PROPERTY_RETURN)
   private Integer _return;
 
+
   public ModelReturn _return(Integer _return) {
+    
     this._return = _return;
     return this;
   }
@@ -42,10 +44,15 @@ public class ModelReturn {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_RETURN)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Integer getReturn() {
     return _return;
   }
 
+
+
   public void setReturn(Integer _return) {
     this._return = _return;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/Name.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -28,22 +29,20 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class Name {
   public static final String JSON_PROPERTY_NAME = "name";
-  @JsonProperty(JSON_PROPERTY_NAME)
   private Integer name;
 
   public static final String JSON_PROPERTY_SNAKE_CASE = "snake_case";
-  @JsonProperty(JSON_PROPERTY_SNAKE_CASE)
   private Integer snakeCase;
 
   public static final String JSON_PROPERTY_PROPERTY = "property";
-  @JsonProperty(JSON_PROPERTY_PROPERTY)
   private String property;
 
   public static final String JSON_PROPERTY_123NUMBER = "123Number";
-  @JsonProperty(JSON_PROPERTY_123NUMBER)
   private Integer _123number;
 
+
   public Name name(Integer name) {
+    
     this.name = name;
     return this;
   }
@@ -53,25 +52,38 @@ public class Name {
    * @return name
   **/
   @ApiModelProperty(required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_NAME)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public Integer getName() {
     return name;
   }
 
+
+
   public void setName(Integer name) {
     this.name = name;
   }
 
+
    /**
    * Get snakeCase
    * @return snakeCase
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_SNAKE_CASE)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Integer getSnakeCase() {
     return snakeCase;
   }
 
+
+
+
   public Name property(String property) {
+    
     this.property = property;
     return this;
   }
@@ -82,25 +94,36 @@ public class Name {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_PROPERTY)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getProperty() {
     return property;
   }
 
+
+
   public void setProperty(String property) {
     this.property = property;
   }
 
+
    /**
    * Get _123number
    * @return _123number
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_123NUMBER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Integer get123number() {
     return _123number;
   }
 
 
+
+
   @Override
   public boolean equals(java.lang.Object o) {
     if (this == o) {

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/NumberOnly.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -28,10 +29,11 @@ import java.math.BigDecimal;
 
 public class NumberOnly {
   public static final String JSON_PROPERTY_JUST_NUMBER = "JustNumber";
-  @JsonProperty(JSON_PROPERTY_JUST_NUMBER)
   private BigDecimal justNumber;
 
+
   public NumberOnly justNumber(BigDecimal justNumber) {
+    
     this.justNumber = justNumber;
     return this;
   }
@@ -42,10 +44,15 @@ public class NumberOnly {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_JUST_NUMBER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public BigDecimal getJustNumber() {
     return justNumber;
   }
 
+
+
   public void setJustNumber(BigDecimal justNumber) {
     this.justNumber = justNumber;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/Order.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -28,19 +29,15 @@ import org.threeten.bp.OffsetDateTime;
 
 public class Order {
   public static final String JSON_PROPERTY_ID = "id";
-  @JsonProperty(JSON_PROPERTY_ID)
   private Long id;
 
   public static final String JSON_PROPERTY_PET_ID = "petId";
-  @JsonProperty(JSON_PROPERTY_PET_ID)
   private Long petId;
 
   public static final String JSON_PROPERTY_QUANTITY = "quantity";
-  @JsonProperty(JSON_PROPERTY_QUANTITY)
   private Integer quantity;
 
   public static final String JSON_PROPERTY_SHIP_DATE = "shipDate";
-  @JsonProperty(JSON_PROPERTY_SHIP_DATE)
   private OffsetDateTime shipDate;
 
   /**
@@ -81,14 +78,14 @@ public class Order {
   }
 
   public static final String JSON_PROPERTY_STATUS = "status";
-  @JsonProperty(JSON_PROPERTY_STATUS)
   private StatusEnum status;
 
   public static final String JSON_PROPERTY_COMPLETE = "complete";
-  @JsonProperty(JSON_PROPERTY_COMPLETE)
   private Boolean complete = false;
 
+
   public Order id(Long id) {
+    
     this.id = id;
     return this;
   }
@@ -99,15 +96,22 @@ public class Order {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ID)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Long getId() {
     return id;
   }
 
+
+
   public void setId(Long id) {
     this.id = id;
   }
 
+
   public Order petId(Long petId) {
+    
     this.petId = petId;
     return this;
   }
@@ -118,15 +122,22 @@ public class Order {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_PET_ID)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Long getPetId() {
     return petId;
   }
 
+
+
   public void setPetId(Long petId) {
     this.petId = petId;
   }
 
+
   public Order quantity(Integer quantity) {
+    
     this.quantity = quantity;
     return this;
   }
@@ -137,15 +148,22 @@ public class Order {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_QUANTITY)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Integer getQuantity() {
     return quantity;
   }
 
+
+
   public void setQuantity(Integer quantity) {
     this.quantity = quantity;
   }
 
+
   public Order shipDate(OffsetDateTime shipDate) {
+    
     this.shipDate = shipDate;
     return this;
   }
@@ -156,15 +174,22 @@ public class Order {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_SHIP_DATE)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public OffsetDateTime getShipDate() {
     return shipDate;
   }
 
+
+
   public void setShipDate(OffsetDateTime shipDate) {
     this.shipDate = shipDate;
   }
 
+
   public Order status(StatusEnum status) {
+    
     this.status = status;
     return this;
   }
@@ -175,15 +200,22 @@ public class Order {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "Order Status")
+  @JsonProperty(JSON_PROPERTY_STATUS)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public StatusEnum getStatus() {
     return status;
   }
 
+
+
   public void setStatus(StatusEnum status) {
     this.status = status;
   }
 
+
   public Order complete(Boolean complete) {
+    
     this.complete = complete;
     return this;
   }
@@ -194,10 +226,15 @@ public class Order {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_COMPLETE)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Boolean isComplete() {
     return complete;
   }
 
+
+
   public void setComplete(Boolean complete) {
     this.complete = complete;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/OuterComposite.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -28,18 +29,17 @@ import java.math.BigDecimal;
 
 public class OuterComposite {
   public static final String JSON_PROPERTY_MY_NUMBER = "my_number";
-  @JsonProperty(JSON_PROPERTY_MY_NUMBER)
   private BigDecimal myNumber;
 
   public static final String JSON_PROPERTY_MY_STRING = "my_string";
-  @JsonProperty(JSON_PROPERTY_MY_STRING)
   private String myString;
 
   public static final String JSON_PROPERTY_MY_BOOLEAN = "my_boolean";
-  @JsonProperty(JSON_PROPERTY_MY_BOOLEAN)
   private Boolean myBoolean;
 
+
   public OuterComposite myNumber(BigDecimal myNumber) {
+    
     this.myNumber = myNumber;
     return this;
   }
@@ -50,15 +50,22 @@ public class OuterComposite {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MY_NUMBER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public BigDecimal getMyNumber() {
     return myNumber;
   }
 
+
+
   public void setMyNumber(BigDecimal myNumber) {
     this.myNumber = myNumber;
   }
 
+
   public OuterComposite myString(String myString) {
+    
     this.myString = myString;
     return this;
   }
@@ -69,15 +76,22 @@ public class OuterComposite {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MY_STRING)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getMyString() {
     return myString;
   }
 
+
+
   public void setMyString(String myString) {
     this.myString = myString;
   }
 
+
   public OuterComposite myBoolean(Boolean myBoolean) {
+    
     this.myBoolean = myBoolean;
     return this;
   }
@@ -88,10 +102,15 @@ public class OuterComposite {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MY_BOOLEAN)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Boolean isMyBoolean() {
     return myBoolean;
   }
 
+
+
   public void setMyBoolean(Boolean myBoolean) {
     this.myBoolean = myBoolean;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/Pet.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -31,23 +32,18 @@ import org.openapitools.client.model.Tag;
 
 public class Pet {
   public static final String JSON_PROPERTY_ID = "id";
-  @JsonProperty(JSON_PROPERTY_ID)
   private Long id;
 
   public static final String JSON_PROPERTY_CATEGORY = "category";
-  @JsonProperty(JSON_PROPERTY_CATEGORY)
-  private Category category = null;
+  private Category category;
 
   public static final String JSON_PROPERTY_NAME = "name";
-  @JsonProperty(JSON_PROPERTY_NAME)
   private String name;
 
   public static final String JSON_PROPERTY_PHOTO_URLS = "photoUrls";
-  @JsonProperty(JSON_PROPERTY_PHOTO_URLS)
   private List<String> photoUrls = new ArrayList<String>();
 
   public static final String JSON_PROPERTY_TAGS = "tags";
-  @JsonProperty(JSON_PROPERTY_TAGS)
   private List<Tag> tags = null;
 
   /**
@@ -88,10 +84,11 @@ public class Pet {
   }
 
   public static final String JSON_PROPERTY_STATUS = "status";
-  @JsonProperty(JSON_PROPERTY_STATUS)
   private StatusEnum status;
 
+
   public Pet id(Long id) {
+    
     this.id = id;
     return this;
   }
@@ -102,15 +99,22 @@ public class Pet {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ID)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Long getId() {
     return id;
   }
 
+
+
   public void setId(Long id) {
     this.id = id;
   }
 
+
   public Pet category(Category category) {
+    
     this.category = category;
     return this;
   }
@@ -121,15 +125,22 @@ public class Pet {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_CATEGORY)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Category getCategory() {
     return category;
   }
 
+
+
   public void setCategory(Category category) {
     this.category = category;
   }
 
+
   public Pet name(String name) {
+    
     this.name = name;
     return this;
   }
@@ -139,15 +150,22 @@ public class Pet {
    * @return name
   **/
   @ApiModelProperty(example = "doggie", required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_NAME)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public String getName() {
     return name;
   }
 
+
+
   public void setName(String name) {
     this.name = name;
   }
 
+
   public Pet photoUrls(List<String> photoUrls) {
+    
     this.photoUrls = photoUrls;
     return this;
   }
@@ -162,15 +180,22 @@ public class Pet {
    * @return photoUrls
   **/
   @ApiModelProperty(required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_PHOTO_URLS)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public List<String> getPhotoUrls() {
     return photoUrls;
   }
 
+
+
   public void setPhotoUrls(List<String> photoUrls) {
     this.photoUrls = photoUrls;
   }
 
+
   public Pet tags(List<Tag> tags) {
+    
     this.tags = tags;
     return this;
   }
@@ -189,15 +214,22 @@ public class Pet {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_TAGS)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<Tag> getTags() {
     return tags;
   }
 
+
+
   public void setTags(List<Tag> tags) {
     this.tags = tags;
   }
 
+
   public Pet status(StatusEnum status) {
+    
     this.status = status;
     return this;
   }
@@ -208,10 +240,15 @@ public class Pet {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "pet status in the store")
+  @JsonProperty(JSON_PROPERTY_STATUS)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public StatusEnum getStatus() {
     return status;
   }
 
+
+
   public void setStatus(StatusEnum status) {
     this.status = status;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/ReadOnlyFirst.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -27,24 +28,30 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class ReadOnlyFirst {
   public static final String JSON_PROPERTY_BAR = "bar";
-  @JsonProperty(JSON_PROPERTY_BAR)
   private String bar;
 
   public static final String JSON_PROPERTY_BAZ = "baz";
-  @JsonProperty(JSON_PROPERTY_BAZ)
   private String baz;
 
+
    /**
    * Get bar
    * @return bar
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_BAR)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getBar() {
     return bar;
   }
 
+
+
+
   public ReadOnlyFirst baz(String baz) {
+    
     this.baz = baz;
     return this;
   }
@@ -55,10 +62,15 @@ public class ReadOnlyFirst {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_BAZ)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getBaz() {
     return baz;
   }
 
+
+
   public void setBaz(String baz) {
     this.baz = baz;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/SpecialModelName.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -27,10 +28,11 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class SpecialModelName {
   public static final String JSON_PROPERTY_$_SPECIAL_PROPERTY_NAME = "$special[property.name]";
-  @JsonProperty(JSON_PROPERTY_$_SPECIAL_PROPERTY_NAME)
   private Long $specialPropertyName;
 
+
   public SpecialModelName $specialPropertyName(Long $specialPropertyName) {
+    
     this.$specialPropertyName = $specialPropertyName;
     return this;
   }
@@ -41,10 +43,15 @@ public class SpecialModelName {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_$_SPECIAL_PROPERTY_NAME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Long get$SpecialPropertyName() {
     return $specialPropertyName;
   }
 
+
+
   public void set$SpecialPropertyName(Long $specialPropertyName) {
     this.$specialPropertyName = $specialPropertyName;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/Tag.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -27,14 +28,14 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class Tag {
   public static final String JSON_PROPERTY_ID = "id";
-  @JsonProperty(JSON_PROPERTY_ID)
   private Long id;
 
   public static final String JSON_PROPERTY_NAME = "name";
-  @JsonProperty(JSON_PROPERTY_NAME)
   private String name;
 
+
   public Tag id(Long id) {
+    
     this.id = id;
     return this;
   }
@@ -45,15 +46,22 @@ public class Tag {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ID)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Long getId() {
     return id;
   }
 
+
+
   public void setId(Long id) {
     this.id = id;
   }
 
+
   public Tag name(String name) {
+    
     this.name = name;
     return this;
   }
@@ -64,10 +72,15 @@ public class Tag {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_NAME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getName() {
     return name;
   }
 
+
+
   public void setName(String name) {
     this.name = name;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/TypeHolderDefault.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -30,26 +31,23 @@ import java.util.List;
 
 public class TypeHolderDefault {
   public static final String JSON_PROPERTY_STRING_ITEM = "string_item";
-  @JsonProperty(JSON_PROPERTY_STRING_ITEM)
   private String stringItem = "what";
 
   public static final String JSON_PROPERTY_NUMBER_ITEM = "number_item";
-  @JsonProperty(JSON_PROPERTY_NUMBER_ITEM)
   private BigDecimal numberItem;
 
   public static final String JSON_PROPERTY_INTEGER_ITEM = "integer_item";
-  @JsonProperty(JSON_PROPERTY_INTEGER_ITEM)
   private Integer integerItem;
 
   public static final String JSON_PROPERTY_BOOL_ITEM = "bool_item";
-  @JsonProperty(JSON_PROPERTY_BOOL_ITEM)
   private Boolean boolItem = true;
 
   public static final String JSON_PROPERTY_ARRAY_ITEM = "array_item";
-  @JsonProperty(JSON_PROPERTY_ARRAY_ITEM)
   private List<Integer> arrayItem = new ArrayList<Integer>();
 
+
   public TypeHolderDefault stringItem(String stringItem) {
+    
     this.stringItem = stringItem;
     return this;
   }
@@ -59,15 +57,22 @@ public class TypeHolderDefault {
    * @return stringItem
   **/
   @ApiModelProperty(required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_STRING_ITEM)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public String getStringItem() {
     return stringItem;
   }
 
+
+
   public void setStringItem(String stringItem) {
     this.stringItem = stringItem;
   }
 
+
   public TypeHolderDefault numberItem(BigDecimal numberItem) {
+    
     this.numberItem = numberItem;
     return this;
   }
@@ -77,15 +82,22 @@ public class TypeHolderDefault {
    * @return numberItem
   **/
   @ApiModelProperty(required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_NUMBER_ITEM)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public BigDecimal getNumberItem() {
     return numberItem;
   }
 
+
+
   public void setNumberItem(BigDecimal numberItem) {
     this.numberItem = numberItem;
   }
 
+
   public TypeHolderDefault integerItem(Integer integerItem) {
+    
     this.integerItem = integerItem;
     return this;
   }
@@ -95,15 +107,22 @@ public class TypeHolderDefault {
    * @return integerItem
   **/
   @ApiModelProperty(required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_INTEGER_ITEM)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public Integer getIntegerItem() {
     return integerItem;
   }
 
+
+
   public void setIntegerItem(Integer integerItem) {
     this.integerItem = integerItem;
   }
 
+
   public TypeHolderDefault boolItem(Boolean boolItem) {
+    
     this.boolItem = boolItem;
     return this;
   }
@@ -113,15 +132,22 @@ public class TypeHolderDefault {
    * @return boolItem
   **/
   @ApiModelProperty(required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_BOOL_ITEM)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public Boolean isBoolItem() {
     return boolItem;
   }
 
+
+
   public void setBoolItem(Boolean boolItem) {
     this.boolItem = boolItem;
   }
 
+
   public TypeHolderDefault arrayItem(List<Integer> arrayItem) {
+    
     this.arrayItem = arrayItem;
     return this;
   }
@@ -136,10 +162,15 @@ public class TypeHolderDefault {
    * @return arrayItem
   **/
   @ApiModelProperty(required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_ARRAY_ITEM)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public List<Integer> getArrayItem() {
     return arrayItem;
   }
 
+
+
   public void setArrayItem(List<Integer> arrayItem) {
     this.arrayItem = arrayItem;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/TypeHolderExample.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -30,26 +31,23 @@ import java.util.List;
 
 public class TypeHolderExample {
   public static final String JSON_PROPERTY_STRING_ITEM = "string_item";
-  @JsonProperty(JSON_PROPERTY_STRING_ITEM)
   private String stringItem;
 
   public static final String JSON_PROPERTY_NUMBER_ITEM = "number_item";
-  @JsonProperty(JSON_PROPERTY_NUMBER_ITEM)
   private BigDecimal numberItem;
 
   public static final String JSON_PROPERTY_INTEGER_ITEM = "integer_item";
-  @JsonProperty(JSON_PROPERTY_INTEGER_ITEM)
   private Integer integerItem;
 
   public static final String JSON_PROPERTY_BOOL_ITEM = "bool_item";
-  @JsonProperty(JSON_PROPERTY_BOOL_ITEM)
   private Boolean boolItem;
 
   public static final String JSON_PROPERTY_ARRAY_ITEM = "array_item";
-  @JsonProperty(JSON_PROPERTY_ARRAY_ITEM)
   private List<Integer> arrayItem = new ArrayList<Integer>();
 
+
   public TypeHolderExample stringItem(String stringItem) {
+    
     this.stringItem = stringItem;
     return this;
   }
@@ -59,15 +57,22 @@ public class TypeHolderExample {
    * @return stringItem
   **/
   @ApiModelProperty(example = "what", required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_STRING_ITEM)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public String getStringItem() {
     return stringItem;
   }
 
+
+
   public void setStringItem(String stringItem) {
     this.stringItem = stringItem;
   }
 
+
   public TypeHolderExample numberItem(BigDecimal numberItem) {
+    
     this.numberItem = numberItem;
     return this;
   }
@@ -77,15 +82,22 @@ public class TypeHolderExample {
    * @return numberItem
   **/
   @ApiModelProperty(example = "1.234", required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_NUMBER_ITEM)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public BigDecimal getNumberItem() {
     return numberItem;
   }
 
+
+
   public void setNumberItem(BigDecimal numberItem) {
     this.numberItem = numberItem;
   }
 
+
   public TypeHolderExample integerItem(Integer integerItem) {
+    
     this.integerItem = integerItem;
     return this;
   }
@@ -95,15 +107,22 @@ public class TypeHolderExample {
    * @return integerItem
   **/
   @ApiModelProperty(example = "-2", required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_INTEGER_ITEM)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public Integer getIntegerItem() {
     return integerItem;
   }
 
+
+
   public void setIntegerItem(Integer integerItem) {
     this.integerItem = integerItem;
   }
 
+
   public TypeHolderExample boolItem(Boolean boolItem) {
+    
     this.boolItem = boolItem;
     return this;
   }
@@ -113,15 +132,22 @@ public class TypeHolderExample {
    * @return boolItem
   **/
   @ApiModelProperty(example = "true", required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_BOOL_ITEM)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public Boolean isBoolItem() {
     return boolItem;
   }
 
+
+
   public void setBoolItem(Boolean boolItem) {
     this.boolItem = boolItem;
   }
 
+
   public TypeHolderExample arrayItem(List<Integer> arrayItem) {
+    
     this.arrayItem = arrayItem;
     return this;
   }
@@ -136,10 +162,15 @@ public class TypeHolderExample {
    * @return arrayItem
   **/
   @ApiModelProperty(example = "[0, 1, 2, 3]", required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_ARRAY_ITEM)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public List<Integer> getArrayItem() {
     return arrayItem;
   }
 
+
+
   public void setArrayItem(List<Integer> arrayItem) {
     this.arrayItem = arrayItem;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/User.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -27,38 +28,32 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class User {
   public static final String JSON_PROPERTY_ID = "id";
-  @JsonProperty(JSON_PROPERTY_ID)
   private Long id;
 
   public static final String JSON_PROPERTY_USERNAME = "username";
-  @JsonProperty(JSON_PROPERTY_USERNAME)
   private String username;
 
   public static final String JSON_PROPERTY_FIRST_NAME = "firstName";
-  @JsonProperty(JSON_PROPERTY_FIRST_NAME)
   private String firstName;
 
   public static final String JSON_PROPERTY_LAST_NAME = "lastName";
-  @JsonProperty(JSON_PROPERTY_LAST_NAME)
   private String lastName;
 
   public static final String JSON_PROPERTY_EMAIL = "email";
-  @JsonProperty(JSON_PROPERTY_EMAIL)
   private String email;
 
   public static final String JSON_PROPERTY_PASSWORD = "password";
-  @JsonProperty(JSON_PROPERTY_PASSWORD)
   private String password;
 
   public static final String JSON_PROPERTY_PHONE = "phone";
-  @JsonProperty(JSON_PROPERTY_PHONE)
   private String phone;
 
   public static final String JSON_PROPERTY_USER_STATUS = "userStatus";
-  @JsonProperty(JSON_PROPERTY_USER_STATUS)
   private Integer userStatus;
 
+
   public User id(Long id) {
+    
     this.id = id;
     return this;
   }
@@ -69,15 +64,22 @@ public class User {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ID)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Long getId() {
     return id;
   }
 
+
+
   public void setId(Long id) {
     this.id = id;
   }
 
+
   public User username(String username) {
+    
     this.username = username;
     return this;
   }
@@ -88,15 +90,22 @@ public class User {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_USERNAME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getUsername() {
     return username;
   }
 
+
+
   public void setUsername(String username) {
     this.username = username;
   }
 
+
   public User firstName(String firstName) {
+    
     this.firstName = firstName;
     return this;
   }
@@ -107,15 +116,22 @@ public class User {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_FIRST_NAME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getFirstName() {
     return firstName;
   }
 
+
+
   public void setFirstName(String firstName) {
     this.firstName = firstName;
   }
 
+
   public User lastName(String lastName) {
+    
     this.lastName = lastName;
     return this;
   }
@@ -126,15 +142,22 @@ public class User {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_LAST_NAME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getLastName() {
     return lastName;
   }
 
+
+
   public void setLastName(String lastName) {
     this.lastName = lastName;
   }
 
+
   public User email(String email) {
+    
     this.email = email;
     return this;
   }
@@ -145,15 +168,22 @@ public class User {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_EMAIL)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getEmail() {
     return email;
   }
 
+
+
   public void setEmail(String email) {
     this.email = email;
   }
 
+
   public User password(String password) {
+    
     this.password = password;
     return this;
   }
@@ -164,15 +194,22 @@ public class User {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_PASSWORD)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getPassword() {
     return password;
   }
 
+
+
   public void setPassword(String password) {
     this.password = password;
   }
 
+
   public User phone(String phone) {
+    
     this.phone = phone;
     return this;
   }
@@ -183,15 +220,22 @@ public class User {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_PHONE)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getPhone() {
     return phone;
   }
 
+
+
   public void setPhone(String phone) {
     this.phone = phone;
   }
 
+
   public User userStatus(Integer userStatus) {
+    
     this.userStatus = userStatus;
     return this;
   }
@@ -202,10 +246,15 @@ public class User {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "User Status")
+  @JsonProperty(JSON_PROPERTY_USER_STATUS)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Integer getUserStatus() {
     return userStatus;
   }
 
+
+
   public void setUserStatus(Integer userStatus) {
     this.userStatus = userStatus;
   }

samples/client/petstore/java/feign/src/main/java/org/openapitools/client/model/XmlItem.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -30,122 +31,95 @@ import java.util.List;
 
 public class XmlItem {
   public static final String JSON_PROPERTY_ATTRIBUTE_STRING = "attribute_string";
-  @JsonProperty(JSON_PROPERTY_ATTRIBUTE_STRING)
   private String attributeString;
 
   public static final String JSON_PROPERTY_ATTRIBUTE_NUMBER = "attribute_number";
-  @JsonProperty(JSON_PROPERTY_ATTRIBUTE_NUMBER)
   private BigDecimal attributeNumber;
 
   public static final String JSON_PROPERTY_ATTRIBUTE_INTEGER = "attribute_integer";
-  @JsonProperty(JSON_PROPERTY_ATTRIBUTE_INTEGER)
   private Integer attributeInteger;
 
   public static final String JSON_PROPERTY_ATTRIBUTE_BOOLEAN = "attribute_boolean";
-  @JsonProperty(JSON_PROPERTY_ATTRIBUTE_BOOLEAN)
   private Boolean attributeBoolean;
 
   public static final String JSON_PROPERTY_WRAPPED_ARRAY = "wrapped_array";
-  @JsonProperty(JSON_PROPERTY_WRAPPED_ARRAY)
   private List<Integer> wrappedArray = null;
 
   public static final String JSON_PROPERTY_NAME_STRING = "name_string";
-  @JsonProperty(JSON_PROPERTY_NAME_STRING)
   private String nameString;
 
   public static final String JSON_PROPERTY_NAME_NUMBER = "name_number";
-  @JsonProperty(JSON_PROPERTY_NAME_NUMBER)
   private BigDecimal nameNumber;
 
   public static final String JSON_PROPERTY_NAME_INTEGER = "name_integer";
-  @JsonProperty(JSON_PROPERTY_NAME_INTEGER)
   private Integer nameInteger;
 
   public static final String JSON_PROPERTY_NAME_BOOLEAN = "name_boolean";
-  @JsonProperty(JSON_PROPERTY_NAME_BOOLEAN)
   private Boolean nameBoolean;
 
   public static final String JSON_PROPERTY_NAME_ARRAY = "name_array";
-  @JsonProperty(JSON_PROPERTY_NAME_ARRAY)
   private List<Integer> nameArray = null;
 
   public static final String JSON_PROPERTY_NAME_WRAPPED_ARRAY = "name_wrapped_array";
-  @JsonProperty(JSON_PROPERTY_NAME_WRAPPED_ARRAY)
   private List<Integer> nameWrappedArray = null;
 
   public static final String JSON_PROPERTY_PREFIX_STRING = "prefix_string";
-  @JsonProperty(JSON_PROPERTY_PREFIX_STRING)
   private String prefixString;
 
   public static final String JSON_PROPERTY_PREFIX_NUMBER = "prefix_number";
-  @JsonProperty(JSON_PROPERTY_PREFIX_NUMBER)
   private BigDecimal prefixNumber;
 
   public static final String JSON_PROPERTY_PREFIX_INTEGER = "prefix_integer";
-  @JsonProperty(JSON_PROPERTY_PREFIX_INTEGER)
   private Integer prefixInteger;
 
   public static final String JSON_PROPERTY_PREFIX_BOOLEAN = "prefix_boolean";
-  @JsonProperty(JSON_PROPERTY_PREFIX_BOOLEAN)
   private Boolean prefixBoolean;
 
   public static final String JSON_PROPERTY_PREFIX_ARRAY = "prefix_array";
-  @JsonProperty(JSON_PROPERTY_PREFIX_ARRAY)
   private List<Integer> prefixArray = null;
 
   public static final String JSON_PROPERTY_PREFIX_WRAPPED_ARRAY = "prefix_wrapped_array";
-  @JsonProperty(JSON_PROPERTY_PREFIX_WRAPPED_ARRAY)
   private List<Integer> prefixWrappedArray = null;
 
   public static final String JSON_PROPERTY_NAMESPACE_STRING = "namespace_string";
-  @JsonProperty(JSON_PROPERTY_NAMESPACE_STRING)
   private String namespaceString;
 
   public static final String JSON_PROPERTY_NAMESPACE_NUMBER = "namespace_number";
-  @JsonProperty(JSON_PROPERTY_NAMESPACE_NUMBER)
   private BigDecimal namespaceNumber;
 
   public static final String JSON_PROPERTY_NAMESPACE_INTEGER = "namespace_integer";
-  @JsonProperty(JSON_PROPERTY_NAMESPACE_INTEGER)
   private Integer namespaceInteger;
 
   public static final String JSON_PROPERTY_NAMESPACE_BOOLEAN = "namespace_boolean";
-  @JsonProperty(JSON_PROPERTY_NAMESPACE_BOOLEAN)
   private Boolean namespaceBoolean;
 
   public static final String JSON_PROPERTY_NAMESPACE_ARRAY = "namespace_array";
-  @JsonProperty(JSON_PROPERTY_NAMESPACE_ARRAY)
   private List<Integer> namespaceArray = null;
 
   public static final String JSON_PROPERTY_NAMESPACE_WRAPPED_ARRAY = "namespace_wrapped_array";
-  @JsonProperty(JSON_PROPERTY_NAMESPACE_WRAPPED_ARRAY)
   private List<Integer> namespaceWrappedArray = null;
 
   public static final String JSON_PROPERTY_PREFIX_NS_STRING = "prefix_ns_string";
-  @JsonProperty(JSON_PROPERTY_PREFIX_NS_STRING)
   private String prefixNsString;
 
   public static final String JSON_PROPERTY_PREFIX_NS_NUMBER = "prefix_ns_number";
-  @JsonProperty(JSON_PROPERTY_PREFIX_NS_NUMBER)
   private BigDecimal prefixNsNumber;
 
   public static final String JSON_PROPERTY_PREFIX_NS_INTEGER = "prefix_ns_integer";
-  @JsonProperty(JSON_PROPERTY_PREFIX_NS_INTEGER)
   private Integer prefixNsInteger;
 
   public static final String JSON_PROPERTY_PREFIX_NS_BOOLEAN = "prefix_ns_boolean";
-  @JsonProperty(JSON_PROPERTY_PREFIX_NS_BOOLEAN)
   private Boolean prefixNsBoolean;
 
   public static final String JSON_PROPERTY_PREFIX_NS_ARRAY = "prefix_ns_array";
-  @JsonProperty(JSON_PROPERTY_PREFIX_NS_ARRAY)
   private List<Integer> prefixNsArray = null;
 
   public static final String JSON_PROPERTY_PREFIX_NS_WRAPPED_ARRAY = "prefix_ns_wrapped_array";
-  @JsonProperty(JSON_PROPERTY_PREFIX_NS_WRAPPED_ARRAY)
   private List<Integer> prefixNsWrappedArray = null;
 
+
   public XmlItem attributeString(String attributeString) {
+    
     this.attributeString = attributeString;
     return this;
   }
@@ -156,15 +130,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(example = "string", value = "")
+  @JsonProperty(JSON_PROPERTY_ATTRIBUTE_STRING)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getAttributeString() {
     return attributeString;
   }
 
+
+
   public void setAttributeString(String attributeString) {
     this.attributeString = attributeString;
   }
 
+
   public XmlItem attributeNumber(BigDecimal attributeNumber) {
+    
     this.attributeNumber = attributeNumber;
     return this;
   }
@@ -175,15 +156,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(example = "1.234", value = "")
+  @JsonProperty(JSON_PROPERTY_ATTRIBUTE_NUMBER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public BigDecimal getAttributeNumber() {
     return attributeNumber;
   }
 
+
+
   public void setAttributeNumber(BigDecimal attributeNumber) {
     this.attributeNumber = attributeNumber;
   }
 
+
   public XmlItem attributeInteger(Integer attributeInteger) {
+    
     this.attributeInteger = attributeInteger;
     return this;
   }
@@ -194,15 +182,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(example = "-2", value = "")
+  @JsonProperty(JSON_PROPERTY_ATTRIBUTE_INTEGER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Integer getAttributeInteger() {
     return attributeInteger;
   }
 
+
+
   public void setAttributeInteger(Integer attributeInteger) {
     this.attributeInteger = attributeInteger;
   }
 
+
   public XmlItem attributeBoolean(Boolean attributeBoolean) {
+    
     this.attributeBoolean = attributeBoolean;
     return this;
   }
@@ -213,15 +208,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(example = "true", value = "")
+  @JsonProperty(JSON_PROPERTY_ATTRIBUTE_BOOLEAN)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Boolean isAttributeBoolean() {
     return attributeBoolean;
   }
 
+
+
   public void setAttributeBoolean(Boolean attributeBoolean) {
     this.attributeBoolean = attributeBoolean;
   }
 
+
   public XmlItem wrappedArray(List<Integer> wrappedArray) {
+    
     this.wrappedArray = wrappedArray;
     return this;
   }
@@ -240,15 +242,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_WRAPPED_ARRAY)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<Integer> getWrappedArray() {
     return wrappedArray;
   }
 
+
+
   public void setWrappedArray(List<Integer> wrappedArray) {
     this.wrappedArray = wrappedArray;
   }
 
+
   public XmlItem nameString(String nameString) {
+    
     this.nameString = nameString;
     return this;
   }
@@ -259,15 +268,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(example = "string", value = "")
+  @JsonProperty(JSON_PROPERTY_NAME_STRING)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getNameString() {
     return nameString;
   }
 
+
+
   public void setNameString(String nameString) {
     this.nameString = nameString;
   }
 
+
   public XmlItem nameNumber(BigDecimal nameNumber) {
+    
     this.nameNumber = nameNumber;
     return this;
   }
@@ -278,15 +294,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(example = "1.234", value = "")
+  @JsonProperty(JSON_PROPERTY_NAME_NUMBER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public BigDecimal getNameNumber() {
     return nameNumber;
   }
 
+
+
   public void setNameNumber(BigDecimal nameNumber) {
     this.nameNumber = nameNumber;
   }
 
+
   public XmlItem nameInteger(Integer nameInteger) {
+    
     this.nameInteger = nameInteger;
     return this;
   }
@@ -297,15 +320,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(example = "-2", value = "")
+  @JsonProperty(JSON_PROPERTY_NAME_INTEGER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Integer getNameInteger() {
     return nameInteger;
   }
 
+
+
   public void setNameInteger(Integer nameInteger) {
     this.nameInteger = nameInteger;
   }
 
+
   public XmlItem nameBoolean(Boolean nameBoolean) {
+    
     this.nameBoolean = nameBoolean;
     return this;
   }
@@ -316,15 +346,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(example = "true", value = "")
+  @JsonProperty(JSON_PROPERTY_NAME_BOOLEAN)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Boolean isNameBoolean() {
     return nameBoolean;
   }
 
+
+
   public void setNameBoolean(Boolean nameBoolean) {
     this.nameBoolean = nameBoolean;
   }
 
+
   public XmlItem nameArray(List<Integer> nameArray) {
+    
     this.nameArray = nameArray;
     return this;
   }
@@ -343,15 +380,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_NAME_ARRAY)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<Integer> getNameArray() {
     return nameArray;
   }
 
+
+
   public void setNameArray(List<Integer> nameArray) {
     this.nameArray = nameArray;
   }
 
+
   public XmlItem nameWrappedArray(List<Integer> nameWrappedArray) {
+    
     this.nameWrappedArray = nameWrappedArray;
     return this;
   }
@@ -370,15 +414,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_NAME_WRAPPED_ARRAY)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<Integer> getNameWrappedArray() {
     return nameWrappedArray;
   }
 
+
+
   public void setNameWrappedArray(List<Integer> nameWrappedArray) {
     this.nameWrappedArray = nameWrappedArray;
   }
 
+
   public XmlItem prefixString(String prefixString) {
+    
     this.prefixString = prefixString;
     return this;
   }
@@ -389,15 +440,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(example = "string", value = "")
+  @JsonProperty(JSON_PROPERTY_PREFIX_STRING)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getPrefixString() {
     return prefixString;
   }
 
+
+
   public void setPrefixString(String prefixString) {
     this.prefixString = prefixString;
   }
 
+
   public XmlItem prefixNumber(BigDecimal prefixNumber) {
+    
     this.prefixNumber = prefixNumber;
     return this;
   }
@@ -408,15 +466,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(example = "1.234", value = "")
+  @JsonProperty(JSON_PROPERTY_PREFIX_NUMBER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public BigDecimal getPrefixNumber() {
     return prefixNumber;
   }
 
+
+
   public void setPrefixNumber(BigDecimal prefixNumber) {
     this.prefixNumber = prefixNumber;
   }
 
+
   public XmlItem prefixInteger(Integer prefixInteger) {
+    
     this.prefixInteger = prefixInteger;
     return this;
   }
@@ -427,15 +492,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(example = "-2", value = "")
+  @JsonProperty(JSON_PROPERTY_PREFIX_INTEGER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Integer getPrefixInteger() {
     return prefixInteger;
   }
 
+
+
   public void setPrefixInteger(Integer prefixInteger) {
     this.prefixInteger = prefixInteger;
   }
 
+
   public XmlItem prefixBoolean(Boolean prefixBoolean) {
+    
     this.prefixBoolean = prefixBoolean;
     return this;
   }
@@ -446,15 +518,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(example = "true", value = "")
+  @JsonProperty(JSON_PROPERTY_PREFIX_BOOLEAN)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Boolean isPrefixBoolean() {
     return prefixBoolean;
   }
 
+
+
   public void setPrefixBoolean(Boolean prefixBoolean) {
     this.prefixBoolean = prefixBoolean;
   }
 
+
   public XmlItem prefixArray(List<Integer> prefixArray) {
+    
     this.prefixArray = prefixArray;
     return this;
   }
@@ -473,15 +552,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_PREFIX_ARRAY)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<Integer> getPrefixArray() {
     return prefixArray;
   }
 
+
+
   public void setPrefixArray(List<Integer> prefixArray) {
     this.prefixArray = prefixArray;
   }
 
+
   public XmlItem prefixWrappedArray(List<Integer> prefixWrappedArray) {
+    
     this.prefixWrappedArray = prefixWrappedArray;
     return this;
   }
@@ -500,15 +586,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_PREFIX_WRAPPED_ARRAY)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<Integer> getPrefixWrappedArray() {
     return prefixWrappedArray;
   }
 
+
+
   public void setPrefixWrappedArray(List<Integer> prefixWrappedArray) {
     this.prefixWrappedArray = prefixWrappedArray;
   }
 
+
   public XmlItem namespaceString(String namespaceString) {
+    
     this.namespaceString = namespaceString;
     return this;
   }
@@ -519,15 +612,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(example = "string", value = "")
+  @JsonProperty(JSON_PROPERTY_NAMESPACE_STRING)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getNamespaceString() {
     return namespaceString;
   }
 
+
+
   public void setNamespaceString(String namespaceString) {
     this.namespaceString = namespaceString;
   }
 
+
   public XmlItem namespaceNumber(BigDecimal namespaceNumber) {
+    
     this.namespaceNumber = namespaceNumber;
     return this;
   }
@@ -538,15 +638,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(example = "1.234", value = "")
+  @JsonProperty(JSON_PROPERTY_NAMESPACE_NUMBER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public BigDecimal getNamespaceNumber() {
     return namespaceNumber;
   }
 
+
+
   public void setNamespaceNumber(BigDecimal namespaceNumber) {
     this.namespaceNumber = namespaceNumber;
   }
 
+
   public XmlItem namespaceInteger(Integer namespaceInteger) {
+    
     this.namespaceInteger = namespaceInteger;
     return this;
   }
@@ -557,15 +664,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(example = "-2", value = "")
+  @JsonProperty(JSON_PROPERTY_NAMESPACE_INTEGER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Integer getNamespaceInteger() {
     return namespaceInteger;
   }
 
+
+
   public void setNamespaceInteger(Integer namespaceInteger) {
     this.namespaceInteger = namespaceInteger;
   }
 
+
   public XmlItem namespaceBoolean(Boolean namespaceBoolean) {
+    
     this.namespaceBoolean = namespaceBoolean;
     return this;
   }
@@ -576,15 +690,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(example = "true", value = "")
+  @JsonProperty(JSON_PROPERTY_NAMESPACE_BOOLEAN)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Boolean isNamespaceBoolean() {
     return namespaceBoolean;
   }
 
+
+
   public void setNamespaceBoolean(Boolean namespaceBoolean) {
     this.namespaceBoolean = namespaceBoolean;
   }
 
+
   public XmlItem namespaceArray(List<Integer> namespaceArray) {
+    
     this.namespaceArray = namespaceArray;
     return this;
   }
@@ -603,15 +724,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_NAMESPACE_ARRAY)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<Integer> getNamespaceArray() {
     return namespaceArray;
   }
 
+
+
   public void setNamespaceArray(List<Integer> namespaceArray) {
     this.namespaceArray = namespaceArray;
   }
 
+
   public XmlItem namespaceWrappedArray(List<Integer> namespaceWrappedArray) {
+    
     this.namespaceWrappedArray = namespaceWrappedArray;
     return this;
   }
@@ -630,15 +758,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_NAMESPACE_WRAPPED_ARRAY)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<Integer> getNamespaceWrappedArray() {
     return namespaceWrappedArray;
   }
 
+
+
   public void setNamespaceWrappedArray(List<Integer> namespaceWrappedArray) {
     this.namespaceWrappedArray = namespaceWrappedArray;
   }
 
+
   public XmlItem prefixNsString(String prefixNsString) {
+    
     this.prefixNsString = prefixNsString;
     return this;
   }
@@ -649,15 +784,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(example = "string", value = "")
+  @JsonProperty(JSON_PROPERTY_PREFIX_NS_STRING)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getPrefixNsString() {
     return prefixNsString;
   }
 
+
+
   public void setPrefixNsString(String prefixNsString) {
     this.prefixNsString = prefixNsString;
   }
 
+
   public XmlItem prefixNsNumber(BigDecimal prefixNsNumber) {
+    
     this.prefixNsNumber = prefixNsNumber;
     return this;
   }
@@ -668,15 +810,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(example = "1.234", value = "")
+  @JsonProperty(JSON_PROPERTY_PREFIX_NS_NUMBER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public BigDecimal getPrefixNsNumber() {
     return prefixNsNumber;
   }
 
+
+
   public void setPrefixNsNumber(BigDecimal prefixNsNumber) {
     this.prefixNsNumber = prefixNsNumber;
   }
 
+
   public XmlItem prefixNsInteger(Integer prefixNsInteger) {
+    
     this.prefixNsInteger = prefixNsInteger;
     return this;
   }
@@ -687,15 +836,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(example = "-2", value = "")
+  @JsonProperty(JSON_PROPERTY_PREFIX_NS_INTEGER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Integer getPrefixNsInteger() {
     return prefixNsInteger;
   }
 
+
+
   public void setPrefixNsInteger(Integer prefixNsInteger) {
     this.prefixNsInteger = prefixNsInteger;
   }
 
+
   public XmlItem prefixNsBoolean(Boolean prefixNsBoolean) {
+    
     this.prefixNsBoolean = prefixNsBoolean;
     return this;
   }
@@ -706,15 +862,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(example = "true", value = "")
+  @JsonProperty(JSON_PROPERTY_PREFIX_NS_BOOLEAN)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Boolean isPrefixNsBoolean() {
     return prefixNsBoolean;
   }
 
+
+
   public void setPrefixNsBoolean(Boolean prefixNsBoolean) {
     this.prefixNsBoolean = prefixNsBoolean;
   }
 
+
   public XmlItem prefixNsArray(List<Integer> prefixNsArray) {
+    
     this.prefixNsArray = prefixNsArray;
     return this;
   }
@@ -733,15 +896,22 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_PREFIX_NS_ARRAY)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<Integer> getPrefixNsArray() {
     return prefixNsArray;
   }
 
+
+
   public void setPrefixNsArray(List<Integer> prefixNsArray) {
     this.prefixNsArray = prefixNsArray;
   }
 
+
   public XmlItem prefixNsWrappedArray(List<Integer> prefixNsWrappedArray) {
+    
     this.prefixNsWrappedArray = prefixNsWrappedArray;
     return this;
   }
@@ -760,10 +930,15 @@ public class XmlItem {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_PREFIX_NS_WRAPPED_ARRAY)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<Integer> getPrefixNsWrappedArray() {
     return prefixNsWrappedArray;
   }
 
+
+
   public void setPrefixNsWrappedArray(List<Integer> prefixNsWrappedArray) {
     this.prefixNsWrappedArray = prefixNsWrappedArray;
   }

samples/client/petstore/java/feign10x/pom.xml

@@ -236,6 +236,11 @@
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-databind</artifactId>
             <version>${jackson-databind-version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.openapitools</groupId>
+            <artifactId>jackson-databind-nullable</artifactId>
+            <version>${jackson-databind-nullable-version}</version>
         </dependency>
             <dependency>
                 <groupId>com.github.joschi.jackson</groupId>
@@ -277,6 +282,7 @@
         <feign-version>10.2.3</feign-version>
         <feign-form-version>2.1.0</feign-form-version>
         <jackson-version>2.9.9</jackson-version>
+        <jackson-databind-nullable-version>0.2.0</jackson-databind-nullable-version>
         <jackson-databind-version>2.9.9</jackson-databind-version>
         <jackson-threetenbp-version>2.6.4</jackson-threetenbp-version>
         <junit-version>4.12</junit-version>

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/ApiClient.java

@@ -10,6 +10,7 @@ import org.threeten.bp.*;
 import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.SerializationFeature;
+import org.openapitools.jackson.nullable.JsonNullableModule;
 import com.fasterxml.jackson.datatype.threetenbp.ThreeTenModule;
 
 import feign.Feign;
@@ -143,6 +144,8 @@ public class ApiClient {
     module.addDeserializer(OffsetDateTime.class, CustomInstantDeserializer.OFFSET_DATE_TIME);
     module.addDeserializer(ZonedDateTime.class, CustomInstantDeserializer.ZONED_DATE_TIME);
     objectMapper.registerModule(module);
+    JsonNullableModule jnm = new JsonNullableModule();
+    objectMapper.registerModule(jnm);
     return objectMapper;
   }
 

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/AdditionalPropertiesAnyType.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -29,10 +30,11 @@ import java.util.Map;
 
 public class AdditionalPropertiesAnyType extends HashMap<String, Object> {
   public static final String JSON_PROPERTY_NAME = "name";
-  @JsonProperty(JSON_PROPERTY_NAME)
   private String name;
 
+
   public AdditionalPropertiesAnyType name(String name) {
+    
     this.name = name;
     return this;
   }
@@ -43,10 +45,15 @@ public class AdditionalPropertiesAnyType extends HashMap<String, Object> {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_NAME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getName() {
     return name;
   }
 
+
+
   public void setName(String name) {
     this.name = name;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/AdditionalPropertiesArray.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -30,10 +31,11 @@ import java.util.Map;
 
 public class AdditionalPropertiesArray extends HashMap<String, List> {
   public static final String JSON_PROPERTY_NAME = "name";
-  @JsonProperty(JSON_PROPERTY_NAME)
   private String name;
 
+
   public AdditionalPropertiesArray name(String name) {
+    
     this.name = name;
     return this;
   }
@@ -44,10 +46,15 @@ public class AdditionalPropertiesArray extends HashMap<String, List> {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_NAME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getName() {
     return name;
   }
 
+
+
   public void setName(String name) {
     this.name = name;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/AdditionalPropertiesBoolean.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -29,10 +30,11 @@ import java.util.Map;
 
 public class AdditionalPropertiesBoolean extends HashMap<String, Boolean> {
   public static final String JSON_PROPERTY_NAME = "name";
-  @JsonProperty(JSON_PROPERTY_NAME)
   private String name;
 
+
   public AdditionalPropertiesBoolean name(String name) {
+    
     this.name = name;
     return this;
   }
@@ -43,10 +45,15 @@ public class AdditionalPropertiesBoolean extends HashMap<String, Boolean> {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_NAME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getName() {
     return name;
   }
 
+
+
   public void setName(String name) {
     this.name = name;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/AdditionalPropertiesClass.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -31,50 +32,41 @@ import java.util.Map;
 
 public class AdditionalPropertiesClass {
   public static final String JSON_PROPERTY_MAP_STRING = "map_string";
-  @JsonProperty(JSON_PROPERTY_MAP_STRING)
   private Map<String, String> mapString = null;
 
   public static final String JSON_PROPERTY_MAP_NUMBER = "map_number";
-  @JsonProperty(JSON_PROPERTY_MAP_NUMBER)
   private Map<String, BigDecimal> mapNumber = null;
 
   public static final String JSON_PROPERTY_MAP_INTEGER = "map_integer";
-  @JsonProperty(JSON_PROPERTY_MAP_INTEGER)
   private Map<String, Integer> mapInteger = null;
 
   public static final String JSON_PROPERTY_MAP_BOOLEAN = "map_boolean";
-  @JsonProperty(JSON_PROPERTY_MAP_BOOLEAN)
   private Map<String, Boolean> mapBoolean = null;
 
   public static final String JSON_PROPERTY_MAP_ARRAY_INTEGER = "map_array_integer";
-  @JsonProperty(JSON_PROPERTY_MAP_ARRAY_INTEGER)
   private Map<String, List<Integer>> mapArrayInteger = null;
 
   public static final String JSON_PROPERTY_MAP_ARRAY_ANYTYPE = "map_array_anytype";
-  @JsonProperty(JSON_PROPERTY_MAP_ARRAY_ANYTYPE)
   private Map<String, List<Object>> mapArrayAnytype = null;
 
   public static final String JSON_PROPERTY_MAP_MAP_STRING = "map_map_string";
-  @JsonProperty(JSON_PROPERTY_MAP_MAP_STRING)
   private Map<String, Map<String, String>> mapMapString = null;
 
   public static final String JSON_PROPERTY_MAP_MAP_ANYTYPE = "map_map_anytype";
-  @JsonProperty(JSON_PROPERTY_MAP_MAP_ANYTYPE)
   private Map<String, Map<String, Object>> mapMapAnytype = null;
 
   public static final String JSON_PROPERTY_ANYTYPE1 = "anytype_1";
-  @JsonProperty(JSON_PROPERTY_ANYTYPE1)
-  private Object anytype1 = null;
+  private Object anytype1;
 
   public static final String JSON_PROPERTY_ANYTYPE2 = "anytype_2";
-  @JsonProperty(JSON_PROPERTY_ANYTYPE2)
-  private Object anytype2 = null;
+  private Object anytype2;
 
   public static final String JSON_PROPERTY_ANYTYPE3 = "anytype_3";
-  @JsonProperty(JSON_PROPERTY_ANYTYPE3)
-  private Object anytype3 = null;
+  private Object anytype3;
+
 
   public AdditionalPropertiesClass mapString(Map<String, String> mapString) {
+    
     this.mapString = mapString;
     return this;
   }
@@ -93,15 +85,22 @@ public class AdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MAP_STRING)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, String> getMapString() {
     return mapString;
   }
 
+
+
   public void setMapString(Map<String, String> mapString) {
     this.mapString = mapString;
   }
 
+
   public AdditionalPropertiesClass mapNumber(Map<String, BigDecimal> mapNumber) {
+    
     this.mapNumber = mapNumber;
     return this;
   }
@@ -120,15 +119,22 @@ public class AdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MAP_NUMBER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, BigDecimal> getMapNumber() {
     return mapNumber;
   }
 
+
+
   public void setMapNumber(Map<String, BigDecimal> mapNumber) {
     this.mapNumber = mapNumber;
   }
 
+
   public AdditionalPropertiesClass mapInteger(Map<String, Integer> mapInteger) {
+    
     this.mapInteger = mapInteger;
     return this;
   }
@@ -147,15 +153,22 @@ public class AdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MAP_INTEGER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, Integer> getMapInteger() {
     return mapInteger;
   }
 
+
+
   public void setMapInteger(Map<String, Integer> mapInteger) {
     this.mapInteger = mapInteger;
   }
 
+
   public AdditionalPropertiesClass mapBoolean(Map<String, Boolean> mapBoolean) {
+    
     this.mapBoolean = mapBoolean;
     return this;
   }
@@ -174,15 +187,22 @@ public class AdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MAP_BOOLEAN)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, Boolean> getMapBoolean() {
     return mapBoolean;
   }
 
+
+
   public void setMapBoolean(Map<String, Boolean> mapBoolean) {
     this.mapBoolean = mapBoolean;
   }
 
+
   public AdditionalPropertiesClass mapArrayInteger(Map<String, List<Integer>> mapArrayInteger) {
+    
     this.mapArrayInteger = mapArrayInteger;
     return this;
   }
@@ -201,15 +221,22 @@ public class AdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MAP_ARRAY_INTEGER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, List<Integer>> getMapArrayInteger() {
     return mapArrayInteger;
   }
 
+
+
   public void setMapArrayInteger(Map<String, List<Integer>> mapArrayInteger) {
     this.mapArrayInteger = mapArrayInteger;
   }
 
+
   public AdditionalPropertiesClass mapArrayAnytype(Map<String, List<Object>> mapArrayAnytype) {
+    
     this.mapArrayAnytype = mapArrayAnytype;
     return this;
   }
@@ -228,15 +255,22 @@ public class AdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MAP_ARRAY_ANYTYPE)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, List<Object>> getMapArrayAnytype() {
     return mapArrayAnytype;
   }
 
+
+
   public void setMapArrayAnytype(Map<String, List<Object>> mapArrayAnytype) {
     this.mapArrayAnytype = mapArrayAnytype;
   }
 
+
   public AdditionalPropertiesClass mapMapString(Map<String, Map<String, String>> mapMapString) {
+    
     this.mapMapString = mapMapString;
     return this;
   }
@@ -255,15 +289,22 @@ public class AdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MAP_MAP_STRING)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, Map<String, String>> getMapMapString() {
     return mapMapString;
   }
 
+
+
   public void setMapMapString(Map<String, Map<String, String>> mapMapString) {
     this.mapMapString = mapMapString;
   }
 
+
   public AdditionalPropertiesClass mapMapAnytype(Map<String, Map<String, Object>> mapMapAnytype) {
+    
     this.mapMapAnytype = mapMapAnytype;
     return this;
   }
@@ -282,15 +323,22 @@ public class AdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MAP_MAP_ANYTYPE)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, Map<String, Object>> getMapMapAnytype() {
     return mapMapAnytype;
   }
 
+
+
   public void setMapMapAnytype(Map<String, Map<String, Object>> mapMapAnytype) {
     this.mapMapAnytype = mapMapAnytype;
   }
 
+
   public AdditionalPropertiesClass anytype1(Object anytype1) {
+    
     this.anytype1 = anytype1;
     return this;
   }
@@ -301,15 +349,22 @@ public class AdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ANYTYPE1)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Object getAnytype1() {
     return anytype1;
   }
 
+
+
   public void setAnytype1(Object anytype1) {
     this.anytype1 = anytype1;
   }
 
+
   public AdditionalPropertiesClass anytype2(Object anytype2) {
+    
     this.anytype2 = anytype2;
     return this;
   }
@@ -320,15 +375,22 @@ public class AdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ANYTYPE2)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Object getAnytype2() {
     return anytype2;
   }
 
+
+
   public void setAnytype2(Object anytype2) {
     this.anytype2 = anytype2;
   }
 
+
   public AdditionalPropertiesClass anytype3(Object anytype3) {
+    
     this.anytype3 = anytype3;
     return this;
   }
@@ -339,10 +401,15 @@ public class AdditionalPropertiesClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ANYTYPE3)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Object getAnytype3() {
     return anytype3;
   }
 
+
+
   public void setAnytype3(Object anytype3) {
     this.anytype3 = anytype3;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/AdditionalPropertiesInteger.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -29,10 +30,11 @@ import java.util.Map;
 
 public class AdditionalPropertiesInteger extends HashMap<String, Integer> {
   public static final String JSON_PROPERTY_NAME = "name";
-  @JsonProperty(JSON_PROPERTY_NAME)
   private String name;
 
+
   public AdditionalPropertiesInteger name(String name) {
+    
     this.name = name;
     return this;
   }
@@ -43,10 +45,15 @@ public class AdditionalPropertiesInteger extends HashMap<String, Integer> {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_NAME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getName() {
     return name;
   }
 
+
+
   public void setName(String name) {
     this.name = name;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/AdditionalPropertiesNumber.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -30,10 +31,11 @@ import java.util.Map;
 
 public class AdditionalPropertiesNumber extends HashMap<String, BigDecimal> {
   public static final String JSON_PROPERTY_NAME = "name";
-  @JsonProperty(JSON_PROPERTY_NAME)
   private String name;
 
+
   public AdditionalPropertiesNumber name(String name) {
+    
     this.name = name;
     return this;
   }
@@ -44,10 +46,15 @@ public class AdditionalPropertiesNumber extends HashMap<String, BigDecimal> {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_NAME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getName() {
     return name;
   }
 
+
+
   public void setName(String name) {
     this.name = name;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/AdditionalPropertiesObject.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -29,10 +30,11 @@ import java.util.Map;
 
 public class AdditionalPropertiesObject extends HashMap<String, Map> {
   public static final String JSON_PROPERTY_NAME = "name";
-  @JsonProperty(JSON_PROPERTY_NAME)
   private String name;
 
+
   public AdditionalPropertiesObject name(String name) {
+    
     this.name = name;
     return this;
   }
@@ -43,10 +45,15 @@ public class AdditionalPropertiesObject extends HashMap<String, Map> {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_NAME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getName() {
     return name;
   }
 
+
+
   public void setName(String name) {
     this.name = name;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/AdditionalPropertiesString.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -29,10 +30,11 @@ import java.util.Map;
 
 public class AdditionalPropertiesString extends HashMap<String, String> {
   public static final String JSON_PROPERTY_NAME = "name";
-  @JsonProperty(JSON_PROPERTY_NAME)
   private String name;
 
+
   public AdditionalPropertiesString name(String name) {
+    
     this.name = name;
     return this;
   }
@@ -43,10 +45,15 @@ public class AdditionalPropertiesString extends HashMap<String, String> {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_NAME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getName() {
     return name;
   }
 
+
+
   public void setName(String name) {
     this.name = name;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/Animal.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonSubTypes;
@@ -35,14 +36,14 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class Animal {
   public static final String JSON_PROPERTY_CLASS_NAME = "className";
-  @JsonProperty(JSON_PROPERTY_CLASS_NAME)
   private String className;
 
   public static final String JSON_PROPERTY_COLOR = "color";
-  @JsonProperty(JSON_PROPERTY_COLOR)
   private String color = "red";
 
+
   public Animal className(String className) {
+    
     this.className = className;
     return this;
   }
@@ -52,15 +53,22 @@ public class Animal {
    * @return className
   **/
   @ApiModelProperty(required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_CLASS_NAME)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public String getClassName() {
     return className;
   }
 
+
+
   public void setClassName(String className) {
     this.className = className;
   }
 
+
   public Animal color(String color) {
+    
     this.color = color;
     return this;
   }
@@ -71,10 +79,15 @@ public class Animal {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_COLOR)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getColor() {
     return color;
   }
 
+
+
   public void setColor(String color) {
     this.color = color;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/ArrayOfArrayOfNumberOnly.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -30,10 +31,11 @@ import java.util.List;
 
 public class ArrayOfArrayOfNumberOnly {
   public static final String JSON_PROPERTY_ARRAY_ARRAY_NUMBER = "ArrayArrayNumber";
-  @JsonProperty(JSON_PROPERTY_ARRAY_ARRAY_NUMBER)
   private List<List<BigDecimal>> arrayArrayNumber = null;
 
+
   public ArrayOfArrayOfNumberOnly arrayArrayNumber(List<List<BigDecimal>> arrayArrayNumber) {
+    
     this.arrayArrayNumber = arrayArrayNumber;
     return this;
   }
@@ -52,10 +54,15 @@ public class ArrayOfArrayOfNumberOnly {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ARRAY_ARRAY_NUMBER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<List<BigDecimal>> getArrayArrayNumber() {
     return arrayArrayNumber;
   }
 
+
+
   public void setArrayArrayNumber(List<List<BigDecimal>> arrayArrayNumber) {
     this.arrayArrayNumber = arrayArrayNumber;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/ArrayOfNumberOnly.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -30,10 +31,11 @@ import java.util.List;
 
 public class ArrayOfNumberOnly {
   public static final String JSON_PROPERTY_ARRAY_NUMBER = "ArrayNumber";
-  @JsonProperty(JSON_PROPERTY_ARRAY_NUMBER)
   private List<BigDecimal> arrayNumber = null;
 
+
   public ArrayOfNumberOnly arrayNumber(List<BigDecimal> arrayNumber) {
+    
     this.arrayNumber = arrayNumber;
     return this;
   }
@@ -52,10 +54,15 @@ public class ArrayOfNumberOnly {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ARRAY_NUMBER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<BigDecimal> getArrayNumber() {
     return arrayNumber;
   }
 
+
+
   public void setArrayNumber(List<BigDecimal> arrayNumber) {
     this.arrayNumber = arrayNumber;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/ArrayTest.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -30,18 +31,17 @@ import org.openapitools.client.model.ReadOnlyFirst;
 
 public class ArrayTest {
   public static final String JSON_PROPERTY_ARRAY_OF_STRING = "array_of_string";
-  @JsonProperty(JSON_PROPERTY_ARRAY_OF_STRING)
   private List<String> arrayOfString = null;
 
   public static final String JSON_PROPERTY_ARRAY_ARRAY_OF_INTEGER = "array_array_of_integer";
-  @JsonProperty(JSON_PROPERTY_ARRAY_ARRAY_OF_INTEGER)
   private List<List<Long>> arrayArrayOfInteger = null;
 
   public static final String JSON_PROPERTY_ARRAY_ARRAY_OF_MODEL = "array_array_of_model";
-  @JsonProperty(JSON_PROPERTY_ARRAY_ARRAY_OF_MODEL)
   private List<List<ReadOnlyFirst>> arrayArrayOfModel = null;
 
+
   public ArrayTest arrayOfString(List<String> arrayOfString) {
+    
     this.arrayOfString = arrayOfString;
     return this;
   }
@@ -60,15 +60,22 @@ public class ArrayTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ARRAY_OF_STRING)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<String> getArrayOfString() {
     return arrayOfString;
   }
 
+
+
   public void setArrayOfString(List<String> arrayOfString) {
     this.arrayOfString = arrayOfString;
   }
 
+
   public ArrayTest arrayArrayOfInteger(List<List<Long>> arrayArrayOfInteger) {
+    
     this.arrayArrayOfInteger = arrayArrayOfInteger;
     return this;
   }
@@ -87,15 +94,22 @@ public class ArrayTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ARRAY_ARRAY_OF_INTEGER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<List<Long>> getArrayArrayOfInteger() {
     return arrayArrayOfInteger;
   }
 
+
+
   public void setArrayArrayOfInteger(List<List<Long>> arrayArrayOfInteger) {
     this.arrayArrayOfInteger = arrayArrayOfInteger;
   }
 
+
   public ArrayTest arrayArrayOfModel(List<List<ReadOnlyFirst>> arrayArrayOfModel) {
+    
     this.arrayArrayOfModel = arrayArrayOfModel;
     return this;
   }
@@ -114,10 +128,15 @@ public class ArrayTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ARRAY_ARRAY_OF_MODEL)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<List<ReadOnlyFirst>> getArrayArrayOfModel() {
     return arrayArrayOfModel;
   }
 
+
+
   public void setArrayArrayOfModel(List<List<ReadOnlyFirst>> arrayArrayOfModel) {
     this.arrayArrayOfModel = arrayArrayOfModel;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/Capitalization.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -27,30 +28,26 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class Capitalization {
   public static final String JSON_PROPERTY_SMALL_CAMEL = "smallCamel";
-  @JsonProperty(JSON_PROPERTY_SMALL_CAMEL)
   private String smallCamel;
 
   public static final String JSON_PROPERTY_CAPITAL_CAMEL = "CapitalCamel";
-  @JsonProperty(JSON_PROPERTY_CAPITAL_CAMEL)
   private String capitalCamel;
 
   public static final String JSON_PROPERTY_SMALL_SNAKE = "small_Snake";
-  @JsonProperty(JSON_PROPERTY_SMALL_SNAKE)
   private String smallSnake;
 
   public static final String JSON_PROPERTY_CAPITAL_SNAKE = "Capital_Snake";
-  @JsonProperty(JSON_PROPERTY_CAPITAL_SNAKE)
   private String capitalSnake;
 
   public static final String JSON_PROPERTY_SC_A_E_T_H_FLOW_POINTS = "SCA_ETH_Flow_Points";
-  @JsonProperty(JSON_PROPERTY_SC_A_E_T_H_FLOW_POINTS)
   private String scAETHFlowPoints;
 
   public static final String JSON_PROPERTY_A_T_T_N_A_M_E = "ATT_NAME";
-  @JsonProperty(JSON_PROPERTY_A_T_T_N_A_M_E)
   private String ATT_NAME;
 
+
   public Capitalization smallCamel(String smallCamel) {
+    
     this.smallCamel = smallCamel;
     return this;
   }
@@ -61,15 +58,22 @@ public class Capitalization {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_SMALL_CAMEL)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getSmallCamel() {
     return smallCamel;
   }
 
+
+
   public void setSmallCamel(String smallCamel) {
     this.smallCamel = smallCamel;
   }
 
+
   public Capitalization capitalCamel(String capitalCamel) {
+    
     this.capitalCamel = capitalCamel;
     return this;
   }
@@ -80,15 +84,22 @@ public class Capitalization {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_CAPITAL_CAMEL)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getCapitalCamel() {
     return capitalCamel;
   }
 
+
+
   public void setCapitalCamel(String capitalCamel) {
     this.capitalCamel = capitalCamel;
   }
 
+
   public Capitalization smallSnake(String smallSnake) {
+    
     this.smallSnake = smallSnake;
     return this;
   }
@@ -99,15 +110,22 @@ public class Capitalization {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_SMALL_SNAKE)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getSmallSnake() {
     return smallSnake;
   }
 
+
+
   public void setSmallSnake(String smallSnake) {
     this.smallSnake = smallSnake;
   }
 
+
   public Capitalization capitalSnake(String capitalSnake) {
+    
     this.capitalSnake = capitalSnake;
     return this;
   }
@@ -118,15 +136,22 @@ public class Capitalization {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_CAPITAL_SNAKE)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getCapitalSnake() {
     return capitalSnake;
   }
 
+
+
   public void setCapitalSnake(String capitalSnake) {
     this.capitalSnake = capitalSnake;
   }
 
+
   public Capitalization scAETHFlowPoints(String scAETHFlowPoints) {
+    
     this.scAETHFlowPoints = scAETHFlowPoints;
     return this;
   }
@@ -137,15 +162,22 @@ public class Capitalization {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_SC_A_E_T_H_FLOW_POINTS)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getScAETHFlowPoints() {
     return scAETHFlowPoints;
   }
 
+
+
   public void setScAETHFlowPoints(String scAETHFlowPoints) {
     this.scAETHFlowPoints = scAETHFlowPoints;
   }
 
+
   public Capitalization ATT_NAME(String ATT_NAME) {
+    
     this.ATT_NAME = ATT_NAME;
     return this;
   }
@@ -156,10 +188,15 @@ public class Capitalization {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "Name of the pet ")
+  @JsonProperty(JSON_PROPERTY_A_T_T_N_A_M_E)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getATTNAME() {
     return ATT_NAME;
   }
 
+
+
   public void setATTNAME(String ATT_NAME) {
     this.ATT_NAME = ATT_NAME;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/Cat.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -29,10 +30,11 @@ import org.openapitools.client.model.CatAllOf;
 
 public class Cat extends Animal {
   public static final String JSON_PROPERTY_DECLAWED = "declawed";
-  @JsonProperty(JSON_PROPERTY_DECLAWED)
   private Boolean declawed;
 
+
   public Cat declawed(Boolean declawed) {
+    
     this.declawed = declawed;
     return this;
   }
@@ -43,10 +45,15 @@ public class Cat extends Animal {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_DECLAWED)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Boolean isDeclawed() {
     return declawed;
   }
 
+
+
   public void setDeclawed(Boolean declawed) {
     this.declawed = declawed;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/CatAllOf.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -27,10 +28,11 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class CatAllOf {
   public static final String JSON_PROPERTY_DECLAWED = "declawed";
-  @JsonProperty(JSON_PROPERTY_DECLAWED)
   private Boolean declawed;
 
+
   public CatAllOf declawed(Boolean declawed) {
+    
     this.declawed = declawed;
     return this;
   }
@@ -41,10 +43,15 @@ public class CatAllOf {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_DECLAWED)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Boolean isDeclawed() {
     return declawed;
   }
 
+
+
   public void setDeclawed(Boolean declawed) {
     this.declawed = declawed;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/Category.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -27,14 +28,14 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class Category {
   public static final String JSON_PROPERTY_ID = "id";
-  @JsonProperty(JSON_PROPERTY_ID)
   private Long id;
 
   public static final String JSON_PROPERTY_NAME = "name";
-  @JsonProperty(JSON_PROPERTY_NAME)
   private String name = "default-name";
 
+
   public Category id(Long id) {
+    
     this.id = id;
     return this;
   }
@@ -45,15 +46,22 @@ public class Category {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ID)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Long getId() {
     return id;
   }
 
+
+
   public void setId(Long id) {
     this.id = id;
   }
 
+
   public Category name(String name) {
+    
     this.name = name;
     return this;
   }
@@ -63,10 +71,15 @@ public class Category {
    * @return name
   **/
   @ApiModelProperty(required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_NAME)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public String getName() {
     return name;
   }
 
+
+
   public void setName(String name) {
     this.name = name;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/ClassModel.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -28,10 +29,11 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class ClassModel {
   public static final String JSON_PROPERTY_PROPERTY_CLASS = "_class";
-  @JsonProperty(JSON_PROPERTY_PROPERTY_CLASS)
   private String propertyClass;
 
+
   public ClassModel propertyClass(String propertyClass) {
+    
     this.propertyClass = propertyClass;
     return this;
   }
@@ -42,10 +44,15 @@ public class ClassModel {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_PROPERTY_CLASS)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getPropertyClass() {
     return propertyClass;
   }
 
+
+
   public void setPropertyClass(String propertyClass) {
     this.propertyClass = propertyClass;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/Client.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -27,10 +28,11 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class Client {
   public static final String JSON_PROPERTY_CLIENT = "client";
-  @JsonProperty(JSON_PROPERTY_CLIENT)
   private String client;
 
+
   public Client client(String client) {
+    
     this.client = client;
     return this;
   }
@@ -41,10 +43,15 @@ public class Client {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_CLIENT)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getClient() {
     return client;
   }
 
+
+
   public void setClient(String client) {
     this.client = client;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/Dog.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -29,10 +30,11 @@ import org.openapitools.client.model.DogAllOf;
 
 public class Dog extends Animal {
   public static final String JSON_PROPERTY_BREED = "breed";
-  @JsonProperty(JSON_PROPERTY_BREED)
   private String breed;
 
+
   public Dog breed(String breed) {
+    
     this.breed = breed;
     return this;
   }
@@ -43,10 +45,15 @@ public class Dog extends Animal {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_BREED)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getBreed() {
     return breed;
   }
 
+
+
   public void setBreed(String breed) {
     this.breed = breed;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/DogAllOf.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -27,10 +28,11 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class DogAllOf {
   public static final String JSON_PROPERTY_BREED = "breed";
-  @JsonProperty(JSON_PROPERTY_BREED)
   private String breed;
 
+
   public DogAllOf breed(String breed) {
+    
     this.breed = breed;
     return this;
   }
@@ -41,10 +43,15 @@ public class DogAllOf {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_BREED)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getBreed() {
     return breed;
   }
 
+
+
   public void setBreed(String breed) {
     this.breed = breed;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/EnumArrays.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -64,7 +65,6 @@ public class EnumArrays {
   }
 
   public static final String JSON_PROPERTY_JUST_SYMBOL = "just_symbol";
-  @JsonProperty(JSON_PROPERTY_JUST_SYMBOL)
   private JustSymbolEnum justSymbol;
 
   /**
@@ -103,10 +103,11 @@ public class EnumArrays {
   }
 
   public static final String JSON_PROPERTY_ARRAY_ENUM = "array_enum";
-  @JsonProperty(JSON_PROPERTY_ARRAY_ENUM)
   private List<ArrayEnumEnum> arrayEnum = null;
 
+
   public EnumArrays justSymbol(JustSymbolEnum justSymbol) {
+    
     this.justSymbol = justSymbol;
     return this;
   }
@@ -117,15 +118,22 @@ public class EnumArrays {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_JUST_SYMBOL)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public JustSymbolEnum getJustSymbol() {
     return justSymbol;
   }
 
+
+
   public void setJustSymbol(JustSymbolEnum justSymbol) {
     this.justSymbol = justSymbol;
   }
 
+
   public EnumArrays arrayEnum(List<ArrayEnumEnum> arrayEnum) {
+    
     this.arrayEnum = arrayEnum;
     return this;
   }
@@ -144,10 +152,15 @@ public class EnumArrays {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ARRAY_ENUM)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<ArrayEnumEnum> getArrayEnum() {
     return arrayEnum;
   }
 
+
+
   public void setArrayEnum(List<ArrayEnumEnum> arrayEnum) {
     this.arrayEnum = arrayEnum;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/EnumTest.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -65,7 +66,6 @@ public class EnumTest {
   }
 
   public static final String JSON_PROPERTY_ENUM_STRING = "enum_string";
-  @JsonProperty(JSON_PROPERTY_ENUM_STRING)
   private EnumStringEnum enumString;
 
   /**
@@ -106,7 +106,6 @@ public class EnumTest {
   }
 
   public static final String JSON_PROPERTY_ENUM_STRING_REQUIRED = "enum_string_required";
-  @JsonProperty(JSON_PROPERTY_ENUM_STRING_REQUIRED)
   private EnumStringRequiredEnum enumStringRequired;
 
   /**
@@ -145,7 +144,6 @@ public class EnumTest {
   }
 
   public static final String JSON_PROPERTY_ENUM_INTEGER = "enum_integer";
-  @JsonProperty(JSON_PROPERTY_ENUM_INTEGER)
   private EnumIntegerEnum enumInteger;
 
   /**
@@ -184,14 +182,14 @@ public class EnumTest {
   }
 
   public static final String JSON_PROPERTY_ENUM_NUMBER = "enum_number";
-  @JsonProperty(JSON_PROPERTY_ENUM_NUMBER)
   private EnumNumberEnum enumNumber;
 
   public static final String JSON_PROPERTY_OUTER_ENUM = "outerEnum";
-  @JsonProperty(JSON_PROPERTY_OUTER_ENUM)
   private OuterEnum outerEnum;
 
+
   public EnumTest enumString(EnumStringEnum enumString) {
+    
     this.enumString = enumString;
     return this;
   }
@@ -202,15 +200,22 @@ public class EnumTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ENUM_STRING)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public EnumStringEnum getEnumString() {
     return enumString;
   }
 
+
+
   public void setEnumString(EnumStringEnum enumString) {
     this.enumString = enumString;
   }
 
+
   public EnumTest enumStringRequired(EnumStringRequiredEnum enumStringRequired) {
+    
     this.enumStringRequired = enumStringRequired;
     return this;
   }
@@ -220,15 +225,22 @@ public class EnumTest {
    * @return enumStringRequired
   **/
   @ApiModelProperty(required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_ENUM_STRING_REQUIRED)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public EnumStringRequiredEnum getEnumStringRequired() {
     return enumStringRequired;
   }
 
+
+
   public void setEnumStringRequired(EnumStringRequiredEnum enumStringRequired) {
     this.enumStringRequired = enumStringRequired;
   }
 
+
   public EnumTest enumInteger(EnumIntegerEnum enumInteger) {
+    
     this.enumInteger = enumInteger;
     return this;
   }
@@ -239,15 +251,22 @@ public class EnumTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ENUM_INTEGER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public EnumIntegerEnum getEnumInteger() {
     return enumInteger;
   }
 
+
+
   public void setEnumInteger(EnumIntegerEnum enumInteger) {
     this.enumInteger = enumInteger;
   }
 
+
   public EnumTest enumNumber(EnumNumberEnum enumNumber) {
+    
     this.enumNumber = enumNumber;
     return this;
   }
@@ -258,15 +277,22 @@ public class EnumTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_ENUM_NUMBER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public EnumNumberEnum getEnumNumber() {
     return enumNumber;
   }
 
+
+
   public void setEnumNumber(EnumNumberEnum enumNumber) {
     this.enumNumber = enumNumber;
   }
 
+
   public EnumTest outerEnum(OuterEnum outerEnum) {
+    
     this.outerEnum = outerEnum;
     return this;
   }
@@ -277,10 +303,15 @@ public class EnumTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_OUTER_ENUM)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public OuterEnum getOuterEnum() {
     return outerEnum;
   }
 
+
+
   public void setOuterEnum(OuterEnum outerEnum) {
     this.outerEnum = outerEnum;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/FileSchemaTestClass.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -29,14 +30,14 @@ import java.util.List;
 
 public class FileSchemaTestClass {
   public static final String JSON_PROPERTY_FILE = "file";
-  @JsonProperty(JSON_PROPERTY_FILE)
-  private java.io.File file = null;
+  private java.io.File file;
 
   public static final String JSON_PROPERTY_FILES = "files";
-  @JsonProperty(JSON_PROPERTY_FILES)
   private List<java.io.File> files = null;
 
+
   public FileSchemaTestClass file(java.io.File file) {
+    
     this.file = file;
     return this;
   }
@@ -47,15 +48,22 @@ public class FileSchemaTestClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_FILE)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public java.io.File getFile() {
     return file;
   }
 
+
+
   public void setFile(java.io.File file) {
     this.file = file;
   }
 
+
   public FileSchemaTestClass files(List<java.io.File> files) {
+    
     this.files = files;
     return this;
   }
@@ -74,10 +82,15 @@ public class FileSchemaTestClass {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_FILES)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public List<java.io.File> getFiles() {
     return files;
   }
 
+
+
   public void setFiles(List<java.io.File> files) {
     this.files = files;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/FormatTest.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -32,58 +33,47 @@ import org.threeten.bp.OffsetDateTime;
 
 public class FormatTest {
   public static final String JSON_PROPERTY_INTEGER = "integer";
-  @JsonProperty(JSON_PROPERTY_INTEGER)
   private Integer integer;
 
   public static final String JSON_PROPERTY_INT32 = "int32";
-  @JsonProperty(JSON_PROPERTY_INT32)
   private Integer int32;
 
   public static final String JSON_PROPERTY_INT64 = "int64";
-  @JsonProperty(JSON_PROPERTY_INT64)
   private Long int64;
 
   public static final String JSON_PROPERTY_NUMBER = "number";
-  @JsonProperty(JSON_PROPERTY_NUMBER)
   private BigDecimal number;
 
   public static final String JSON_PROPERTY_FLOAT = "float";
-  @JsonProperty(JSON_PROPERTY_FLOAT)
   private Float _float;
 
   public static final String JSON_PROPERTY_DOUBLE = "double";
-  @JsonProperty(JSON_PROPERTY_DOUBLE)
   private Double _double;
 
   public static final String JSON_PROPERTY_STRING = "string";
-  @JsonProperty(JSON_PROPERTY_STRING)
   private String string;
 
   public static final String JSON_PROPERTY_BYTE = "byte";
-  @JsonProperty(JSON_PROPERTY_BYTE)
   private byte[] _byte;
 
   public static final String JSON_PROPERTY_BINARY = "binary";
-  @JsonProperty(JSON_PROPERTY_BINARY)
   private File binary;
 
   public static final String JSON_PROPERTY_DATE = "date";
-  @JsonProperty(JSON_PROPERTY_DATE)
   private LocalDate date;
 
   public static final String JSON_PROPERTY_DATE_TIME = "dateTime";
-  @JsonProperty(JSON_PROPERTY_DATE_TIME)
   private OffsetDateTime dateTime;
 
   public static final String JSON_PROPERTY_UUID = "uuid";
-  @JsonProperty(JSON_PROPERTY_UUID)
   private UUID uuid;
 
   public static final String JSON_PROPERTY_PASSWORD = "password";
-  @JsonProperty(JSON_PROPERTY_PASSWORD)
   private String password;
 
+
   public FormatTest integer(Integer integer) {
+    
     this.integer = integer;
     return this;
   }
@@ -96,15 +86,22 @@ public class FormatTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_INTEGER)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Integer getInteger() {
     return integer;
   }
 
+
+
   public void setInteger(Integer integer) {
     this.integer = integer;
   }
 
+
   public FormatTest int32(Integer int32) {
+    
     this.int32 = int32;
     return this;
   }
@@ -117,15 +114,22 @@ public class FormatTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_INT32)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Integer getInt32() {
     return int32;
   }
 
+
+
   public void setInt32(Integer int32) {
     this.int32 = int32;
   }
 
+
   public FormatTest int64(Long int64) {
+    
     this.int64 = int64;
     return this;
   }
@@ -136,15 +140,22 @@ public class FormatTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_INT64)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Long getInt64() {
     return int64;
   }
 
+
+
   public void setInt64(Long int64) {
     this.int64 = int64;
   }
 
+
   public FormatTest number(BigDecimal number) {
+    
     this.number = number;
     return this;
   }
@@ -156,15 +167,22 @@ public class FormatTest {
    * @return number
   **/
   @ApiModelProperty(required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_NUMBER)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public BigDecimal getNumber() {
     return number;
   }
 
+
+
   public void setNumber(BigDecimal number) {
     this.number = number;
   }
 
+
   public FormatTest _float(Float _float) {
+    
     this._float = _float;
     return this;
   }
@@ -177,15 +195,22 @@ public class FormatTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_FLOAT)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Float getFloat() {
     return _float;
   }
 
+
+
   public void setFloat(Float _float) {
     this._float = _float;
   }
 
+
   public FormatTest _double(Double _double) {
+    
     this._double = _double;
     return this;
   }
@@ -198,15 +223,22 @@ public class FormatTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_DOUBLE)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Double getDouble() {
     return _double;
   }
 
+
+
   public void setDouble(Double _double) {
     this._double = _double;
   }
 
+
   public FormatTest string(String string) {
+    
     this.string = string;
     return this;
   }
@@ -217,15 +249,22 @@ public class FormatTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_STRING)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getString() {
     return string;
   }
 
+
+
   public void setString(String string) {
     this.string = string;
   }
 
+
   public FormatTest _byte(byte[] _byte) {
+    
     this._byte = _byte;
     return this;
   }
@@ -235,15 +274,22 @@ public class FormatTest {
    * @return _byte
   **/
   @ApiModelProperty(required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_BYTE)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public byte[] getByte() {
     return _byte;
   }
 
+
+
   public void setByte(byte[] _byte) {
     this._byte = _byte;
   }
 
+
   public FormatTest binary(File binary) {
+    
     this.binary = binary;
     return this;
   }
@@ -254,15 +300,22 @@ public class FormatTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_BINARY)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public File getBinary() {
     return binary;
   }
 
+
+
   public void setBinary(File binary) {
     this.binary = binary;
   }
 
+
   public FormatTest date(LocalDate date) {
+    
     this.date = date;
     return this;
   }
@@ -272,15 +325,22 @@ public class FormatTest {
    * @return date
   **/
   @ApiModelProperty(required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_DATE)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public LocalDate getDate() {
     return date;
   }
 
+
+
   public void setDate(LocalDate date) {
     this.date = date;
   }
 
+
   public FormatTest dateTime(OffsetDateTime dateTime) {
+    
     this.dateTime = dateTime;
     return this;
   }
@@ -291,15 +351,22 @@ public class FormatTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_DATE_TIME)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public OffsetDateTime getDateTime() {
     return dateTime;
   }
 
+
+
   public void setDateTime(OffsetDateTime dateTime) {
     this.dateTime = dateTime;
   }
 
+
   public FormatTest uuid(UUID uuid) {
+    
     this.uuid = uuid;
     return this;
   }
@@ -310,15 +377,22 @@ public class FormatTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(example = "72f98069-206d-4f12-9f12-3d1e525a8e84", value = "")
+  @JsonProperty(JSON_PROPERTY_UUID)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public UUID getUuid() {
     return uuid;
   }
 
+
+
   public void setUuid(UUID uuid) {
     this.uuid = uuid;
   }
 
+
   public FormatTest password(String password) {
+    
     this.password = password;
     return this;
   }
@@ -328,10 +402,15 @@ public class FormatTest {
    * @return password
   **/
   @ApiModelProperty(required = true, value = "")
+  @JsonProperty(JSON_PROPERTY_PASSWORD)
+  @JsonInclude(value = JsonInclude.Include.ALWAYS)
+
   public String getPassword() {
     return password;
   }
 
+
+
   public void setPassword(String password) {
     this.password = password;
   }

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/HasOnlyReadOnly.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -27,34 +28,44 @@ import io.swagger.annotations.ApiModelProperty;
 
 public class HasOnlyReadOnly {
   public static final String JSON_PROPERTY_BAR = "bar";
-  @JsonProperty(JSON_PROPERTY_BAR)
   private String bar;
 
   public static final String JSON_PROPERTY_FOO = "foo";
-  @JsonProperty(JSON_PROPERTY_FOO)
   private String foo;
 
+
    /**
    * Get bar
    * @return bar
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_BAR)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getBar() {
     return bar;
   }
 
+
+
+
    /**
    * Get foo
    * @return foo
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_FOO)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public String getFoo() {
     return foo;
   }
 
 
+
+
   @Override
   public boolean equals(java.lang.Object o) {
     if (this == o) {

samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/model/MapTest.java

@@ -15,6 +15,7 @@ package org.openapitools.client.model;
 
 import java.util.Objects;
 import java.util.Arrays;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
@@ -30,7 +31,6 @@ import java.util.Map;
 
 public class MapTest {
   public static final String JSON_PROPERTY_MAP_MAP_OF_STRING = "map_map_of_string";
-  @JsonProperty(JSON_PROPERTY_MAP_MAP_OF_STRING)
   private Map<String, Map<String, String>> mapMapOfString = null;
 
   /**
@@ -69,18 +69,17 @@ public class MapTest {
   }
 
   public static final String JSON_PROPERTY_MAP_OF_ENUM_STRING = "map_of_enum_string";
-  @JsonProperty(JSON_PROPERTY_MAP_OF_ENUM_STRING)
   private Map<String, InnerEnum> mapOfEnumString = null;
 
   public static final String JSON_PROPERTY_DIRECT_MAP = "direct_map";
-  @JsonProperty(JSON_PROPERTY_DIRECT_MAP)
   private Map<String, Boolean> directMap = null;
 
   public static final String JSON_PROPERTY_INDIRECT_MAP = "indirect_map";
-  @JsonProperty(JSON_PROPERTY_INDIRECT_MAP)
   private Map<String, Boolean> indirectMap = null;
 
+
   public MapTest mapMapOfString(Map<String, Map<String, String>> mapMapOfString) {
+    
     this.mapMapOfString = mapMapOfString;
     return this;
   }
@@ -99,15 +98,22 @@ public class MapTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MAP_MAP_OF_STRING)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, Map<String, String>> getMapMapOfString() {
     return mapMapOfString;
   }
 
+
+
   public void setMapMapOfString(Map<String, Map<String, String>> mapMapOfString) {
     this.mapMapOfString = mapMapOfString;
   }
 
+
   public MapTest mapOfEnumString(Map<String, InnerEnum> mapOfEnumString) {
+    
     this.mapOfEnumString = mapOfEnumString;
     return this;
   }
@@ -126,15 +132,22 @@ public class MapTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_MAP_OF_ENUM_STRING)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, InnerEnum> getMapOfEnumString() {
     return mapOfEnumString;
   }
 
+
+
   public void setMapOfEnumString(Map<String, InnerEnum> mapOfEnumString) {
     this.mapOfEnumString = mapOfEnumString;
   }
 
+
   public MapTest directMap(Map<String, Boolean> directMap) {
+    
     this.directMap = directMap;
     return this;
   }
@@ -153,15 +166,22 @@ public class MapTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_DIRECT_MAP)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, Boolean> getDirectMap() {
     return directMap;
   }
 
+
+
   public void setDirectMap(Map<String, Boolean> directMap) {
     this.directMap = directMap;
   }
 
+
   public MapTest indirectMap(Map<String, Boolean> indirectMap) {
+    
     this.indirectMap = indirectMap;
     return this;
   }
@@ -180,10 +200,15 @@ public class MapTest {
   **/
   @javax.annotation.Nullable
   @ApiModelProperty(value = "")
+  @JsonProperty(JSON_PROPERTY_INDIRECT_MAP)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
   public Map<String, Boolean> getIndirectMap() {
     return indirectMap;
   }
 
+
+
   public void setIndirectMap(Map<String, Boolean> indirectMap) {
     this.indirectMap = indirectMap;
   }