Using Optional.ofNullable() at the fluent setters to prevent NPE (#20406)

* * Uses Optional.ofNullable() at the fluent setters to prevent NPE
* Fixes issue #17538

* updates samples

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

@@ -156,7 +156,7 @@ public class {{classname}}{{#parent}} extends {{{parent}}}{{/parent}}{{^parent}}
   {{! begin feature: fluent setter methods }}
   public {{classname}} {{name}}({{{datatypeWithEnum}}} {{name}}) {
     {{#openApiNullable}}
-    this.{{name}} = {{#isNullable}}JsonNullable.of({{/isNullable}}{{#useOptional}}{{^required}}{{^isNullable}}{{^isContainer}}Optional.of({{/isContainer}}{{/isNullable}}{{/required}}{{/useOptional}}{{name}}{{#isNullable}}){{/isNullable}}{{#useOptional}}{{^required}}{{^isNullable}}{{^isContainer}}){{/isContainer}}{{/isNullable}}{{/required}}{{/useOptional}};
+    this.{{name}} = {{#isNullable}}JsonNullable.of({{/isNullable}}{{#useOptional}}{{^required}}{{^isNullable}}{{^isContainer}}Optional.ofNullable({{/isContainer}}{{/isNullable}}{{/required}}{{/useOptional}}{{name}}{{#isNullable}}){{/isNullable}}{{#useOptional}}{{^required}}{{^isNullable}}{{^isContainer}}){{/isContainer}}{{/isNullable}}{{/required}}{{/useOptional}};
     {{/openApiNullable}}
     {{^openApiNullable}}
     this.{{name}} = {{name}};

modules/openapi-generator/src/test/java/org/openapitools/codegen/java/spring/SpringCodegenTest.java

@@ -228,7 +228,7 @@ public class SpringCodegenTest {
                 .containsWithNameAndAttributes("DateTimeFormat", ImmutableMap.of("iso", "DateTimeFormat.ISO.DATE_TIME"))
                 .toProperty().toType()
                 .assertMethod("born", "LocalDate")
-                .bodyContainsLines("this.born = Optional.of(born)")
+                .bodyContainsLines("this.born = Optional.ofNullable(born)")
                 .doesNotHaveComment();
     }
 
@@ -4397,9 +4397,10 @@ public class SpringCodegenTest {
 
     private void assertWrapperMethod(JavaFileAssert javaFileAssert, String wrapperType, String type, String expectedName, String getterReturnType){
         String methodName = StringUtils.capitalize(expectedName);
+        var of = wrapperType.equals("Optional") ? "ofNullable" : "of";
         javaFileAssert.assertMethod(expectedName)
                 .hasReturnType("Animal")
-                .bodyContainsLines("this."+expectedName+" = "+wrapperType+".of("+expectedName+");", "return this;")
+                .bodyContainsLines("this." + expectedName + " = "+wrapperType+ "." + of + "(" +expectedName+");", "return this;")
                 .assertParameter(expectedName)
                 .hasType(type)
                 .toMethod()

samples/openapi3/client/petstore/spring-cloud-3-with-optional/src/main/java/org/openapitools/model/Category.java

@@ -26,7 +26,7 @@ public class Category {
   private Optional<@Pattern(regexp = "^[a-zA-Z0-9]+[a-zA-Z0-9\\.\\-_]*[a-zA-Z0-9]+$") String> name = Optional.empty();
 
   public Category id(Long id) {
-    this.id = Optional.of(id);
+    this.id = Optional.ofNullable(id);
     return this;
   }
 
@@ -45,7 +45,7 @@ public class Category {
   }
 
   public Category name(String name) {
-    this.name = Optional.of(name);
+    this.name = Optional.ofNullable(name);
     return this;
   }
 

samples/openapi3/client/petstore/spring-cloud-3-with-optional/src/main/java/org/openapitools/model/ModelApiResponse.java

@@ -30,7 +30,7 @@ public class ModelApiResponse {
   private Optional<String> message = Optional.empty();
 
   public ModelApiResponse code(Integer code) {
-    this.code = Optional.of(code);
+    this.code = Optional.ofNullable(code);
     return this;
   }
 
@@ -49,7 +49,7 @@ public class ModelApiResponse {
   }
 
   public ModelApiResponse type(String type) {
-    this.type = Optional.of(type);
+    this.type = Optional.ofNullable(type);
     return this;
   }
 
@@ -68,7 +68,7 @@ public class ModelApiResponse {
   }
 
   public ModelApiResponse message(String message) {
-    this.message = Optional.of(message);
+    this.message = Optional.ofNullable(message);
     return this;
   }
 

samples/openapi3/client/petstore/spring-cloud-3-with-optional/src/main/java/org/openapitools/model/Order.java

@@ -75,7 +75,7 @@ public class Order {
   private Optional<Boolean> complete = Optional.of(false);
 
   public Order id(Long id) {
-    this.id = Optional.of(id);
+    this.id = Optional.ofNullable(id);
     return this;
   }
 
@@ -94,7 +94,7 @@ public class Order {
   }
 
   public Order petId(Long petId) {
-    this.petId = Optional.of(petId);
+    this.petId = Optional.ofNullable(petId);
     return this;
   }
 
@@ -113,7 +113,7 @@ public class Order {
   }
 
   public Order quantity(Integer quantity) {
-    this.quantity = Optional.of(quantity);
+    this.quantity = Optional.ofNullable(quantity);
     return this;
   }
 
@@ -132,7 +132,7 @@ public class Order {
   }
 
   public Order shipDate(OffsetDateTime shipDate) {
-    this.shipDate = Optional.of(shipDate);
+    this.shipDate = Optional.ofNullable(shipDate);
     return this;
   }
 
@@ -151,7 +151,7 @@ public class Order {
   }
 
   public Order status(StatusEnum status) {
-    this.status = Optional.of(status);
+    this.status = Optional.ofNullable(status);
     return this;
   }
 
@@ -170,7 +170,7 @@ public class Order {
   }
 
   public Order complete(Boolean complete) {
-    this.complete = Optional.of(complete);
+    this.complete = Optional.ofNullable(complete);
     return this;
   }
 

samples/openapi3/client/petstore/spring-cloud-3-with-optional/src/main/java/org/openapitools/model/Pet.java

@@ -92,7 +92,7 @@ public class Pet {
   }
 
   public Pet id(Long id) {
-    this.id = Optional.of(id);
+    this.id = Optional.ofNullable(id);
     return this;
   }
 
@@ -111,7 +111,7 @@ public class Pet {
   }
 
   public Pet category(Category category) {
-    this.category = Optional.of(category);
+    this.category = Optional.ofNullable(category);
     return this;
   }
 
@@ -203,7 +203,7 @@ public class Pet {
   }
 
   public Pet status(StatusEnum status) {
-    this.status = Optional.of(status);
+    this.status = Optional.ofNullable(status);
     return this;
   }
 

samples/openapi3/client/petstore/spring-cloud-3-with-optional/src/main/java/org/openapitools/model/Tag.java

@@ -26,7 +26,7 @@ public class Tag {
   private Optional<String> name = Optional.empty();
 
   public Tag id(Long id) {
-    this.id = Optional.of(id);
+    this.id = Optional.ofNullable(id);
     return this;
   }
 
@@ -45,7 +45,7 @@ public class Tag {
   }
 
   public Tag name(String name) {
-    this.name = Optional.of(name);
+    this.name = Optional.ofNullable(name);
     return this;
   }
 

samples/openapi3/client/petstore/spring-cloud-3-with-optional/src/main/java/org/openapitools/model/User.java

@@ -38,7 +38,7 @@ public class User {
   private Optional<Integer> userStatus = Optional.empty();
 
   public User id(Long id) {
-    this.id = Optional.of(id);
+    this.id = Optional.ofNullable(id);
     return this;
   }
 
@@ -57,7 +57,7 @@ public class User {
   }
 
   public User username(String username) {
-    this.username = Optional.of(username);
+    this.username = Optional.ofNullable(username);
     return this;
   }
 
@@ -76,7 +76,7 @@ public class User {
   }
 
   public User firstName(String firstName) {
-    this.firstName = Optional.of(firstName);
+    this.firstName = Optional.ofNullable(firstName);
     return this;
   }
 
@@ -95,7 +95,7 @@ public class User {
   }
 
   public User lastName(String lastName) {
-    this.lastName = Optional.of(lastName);
+    this.lastName = Optional.ofNullable(lastName);
     return this;
   }
 
@@ -114,7 +114,7 @@ public class User {
   }
 
   public User email(String email) {
-    this.email = Optional.of(email);
+    this.email = Optional.ofNullable(email);
     return this;
   }
 
@@ -133,7 +133,7 @@ public class User {
   }
 
   public User password(String password) {
-    this.password = Optional.of(password);
+    this.password = Optional.ofNullable(password);
     return this;
   }
 
@@ -152,7 +152,7 @@ public class User {
   }
 
   public User phone(String phone) {
-    this.phone = Optional.of(phone);
+    this.phone = Optional.ofNullable(phone);
     return this;
   }
 
@@ -171,7 +171,7 @@ public class User {
   }
 
   public User userStatus(Integer userStatus) {
-    this.userStatus = Optional.of(userStatus);
+    this.userStatus = Optional.ofNullable(userStatus);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/AdditionalPropertiesAnyType.java

@@ -30,7 +30,7 @@ public class AdditionalPropertiesAnyType {
   private Optional<String> name = Optional.empty();
 
   public AdditionalPropertiesAnyType name(String name) {
-    this.name = Optional.of(name);
+    this.name = Optional.ofNullable(name);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/AdditionalPropertiesArray.java

@@ -31,7 +31,7 @@ public class AdditionalPropertiesArray {
   private Optional<String> name = Optional.empty();
 
   public AdditionalPropertiesArray name(String name) {
-    this.name = Optional.of(name);
+    this.name = Optional.ofNullable(name);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/AdditionalPropertiesBoolean.java

@@ -30,7 +30,7 @@ public class AdditionalPropertiesBoolean {
   private Optional<String> name = Optional.empty();
 
   public AdditionalPropertiesBoolean name(String name) {
-    this.name = Optional.of(name);
+    this.name = Optional.ofNullable(name);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/AdditionalPropertiesClass.java

@@ -285,7 +285,7 @@ public class AdditionalPropertiesClass {
   }
 
   public AdditionalPropertiesClass anytype1(Object anytype1) {
-    this.anytype1 = Optional.of(anytype1);
+    this.anytype1 = Optional.ofNullable(anytype1);
     return this;
   }
 
@@ -325,7 +325,7 @@ public class AdditionalPropertiesClass {
   }
 
   public AdditionalPropertiesClass anytype3(Object anytype3) {
-    this.anytype3 = Optional.of(anytype3);
+    this.anytype3 = Optional.ofNullable(anytype3);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/AdditionalPropertiesInteger.java

@@ -30,7 +30,7 @@ public class AdditionalPropertiesInteger {
   private Optional<String> name = Optional.empty();
 
   public AdditionalPropertiesInteger name(String name) {
-    this.name = Optional.of(name);
+    this.name = Optional.ofNullable(name);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/AdditionalPropertiesNumber.java

@@ -31,7 +31,7 @@ public class AdditionalPropertiesNumber {
   private Optional<String> name = Optional.empty();
 
   public AdditionalPropertiesNumber name(String name) {
-    this.name = Optional.of(name);
+    this.name = Optional.ofNullable(name);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/AdditionalPropertiesObject.java

@@ -31,7 +31,7 @@ public class AdditionalPropertiesObject {
   private Optional<String> name = Optional.empty();
 
   public AdditionalPropertiesObject name(String name) {
-    this.name = Optional.of(name);
+    this.name = Optional.ofNullable(name);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/AdditionalPropertiesString.java

@@ -30,7 +30,7 @@ public class AdditionalPropertiesString {
   private Optional<String> name = Optional.empty();
 
   public AdditionalPropertiesString name(String name) {
-    this.name = Optional.of(name);
+    this.name = Optional.ofNullable(name);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/Animal.java

@@ -73,7 +73,7 @@ public class Animal {
   }
 
   public Animal color(String color) {
-    this.color = Optional.of(color);
+    this.color = Optional.ofNullable(color);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/BigCat.java

@@ -82,7 +82,7 @@ public class BigCat extends Cat {
   }
 
   public BigCat kind(KindEnum kind) {
-    this.kind = Optional.of(kind);
+    this.kind = Optional.ofNullable(kind);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/Capitalization.java

@@ -36,7 +36,7 @@ public class Capitalization {
   private Optional<String> ATT_NAME = Optional.empty();
 
   public Capitalization smallCamel(String smallCamel) {
-    this.smallCamel = Optional.of(smallCamel);
+    this.smallCamel = Optional.ofNullable(smallCamel);
     return this;
   }
 
@@ -56,7 +56,7 @@ public class Capitalization {
   }
 
   public Capitalization capitalCamel(String capitalCamel) {
-    this.capitalCamel = Optional.of(capitalCamel);
+    this.capitalCamel = Optional.ofNullable(capitalCamel);
     return this;
   }
 
@@ -76,7 +76,7 @@ public class Capitalization {
   }
 
   public Capitalization smallSnake(String smallSnake) {
-    this.smallSnake = Optional.of(smallSnake);
+    this.smallSnake = Optional.ofNullable(smallSnake);
     return this;
   }
 
@@ -96,7 +96,7 @@ public class Capitalization {
   }
 
   public Capitalization capitalSnake(String capitalSnake) {
-    this.capitalSnake = Optional.of(capitalSnake);
+    this.capitalSnake = Optional.ofNullable(capitalSnake);
     return this;
   }
 
@@ -116,7 +116,7 @@ public class Capitalization {
   }
 
   public Capitalization scAETHFlowPoints(String scAETHFlowPoints) {
-    this.scAETHFlowPoints = Optional.of(scAETHFlowPoints);
+    this.scAETHFlowPoints = Optional.ofNullable(scAETHFlowPoints);
     return this;
   }
 
@@ -136,7 +136,7 @@ public class Capitalization {
   }
 
   public Capitalization ATT_NAME(String ATT_NAME) {
-    this.ATT_NAME = Optional.of(ATT_NAME);
+    this.ATT_NAME = Optional.ofNullable(ATT_NAME);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/Cat.java

@@ -50,7 +50,7 @@ public class Cat extends Animal {
   }
 
   public Cat declawed(Boolean declawed) {
-    this.declawed = Optional.of(declawed);
+    this.declawed = Optional.ofNullable(declawed);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/Category.java

@@ -39,7 +39,7 @@ public class Category {
   }
 
   public Category id(Long id) {
-    this.id = Optional.of(id);
+    this.id = Optional.ofNullable(id);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/ChildWithNullable.java

@@ -34,7 +34,7 @@ public class ChildWithNullable extends ParentWithNullable {
   private Optional<String> otherProperty = Optional.empty();
 
   public ChildWithNullable otherProperty(String otherProperty) {
-    this.otherProperty = Optional.of(otherProperty);
+    this.otherProperty = Optional.ofNullable(otherProperty);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/ClassModel.java

@@ -27,7 +27,7 @@ public class ClassModel {
   private Optional<String> propertyClass = Optional.empty();
 
   public ClassModel propertyClass(String propertyClass) {
-    this.propertyClass = Optional.of(propertyClass);
+    this.propertyClass = Optional.ofNullable(propertyClass);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/Client.java

@@ -26,7 +26,7 @@ public class Client {
   private Optional<String> client = Optional.empty();
 
   public Client client(String client) {
-    this.client = Optional.of(client);
+    this.client = Optional.ofNullable(client);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/Dog.java

@@ -42,7 +42,7 @@ public class Dog extends Animal {
   }
 
   public Dog breed(String breed) {
-    this.breed = Optional.of(breed);
+    this.breed = Optional.ofNullable(breed);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/EnumArrays.java

@@ -103,7 +103,7 @@ public class EnumArrays {
   private List<ArrayEnumEnum> arrayEnum = new ArrayList<>();
 
   public EnumArrays justSymbol(JustSymbolEnum justSymbol) {
-    this.justSymbol = Optional.of(justSymbol);
+    this.justSymbol = Optional.ofNullable(justSymbol);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/EnumTest.java

@@ -193,7 +193,7 @@ public class EnumTest {
   }
 
   public EnumTest enumString(EnumStringEnum enumString) {
-    this.enumString = Optional.of(enumString);
+    this.enumString = Optional.ofNullable(enumString);
     return this;
   }
 
@@ -233,7 +233,7 @@ public class EnumTest {
   }
 
   public EnumTest enumInteger(EnumIntegerEnum enumInteger) {
-    this.enumInteger = Optional.of(enumInteger);
+    this.enumInteger = Optional.ofNullable(enumInteger);
     return this;
   }
 
@@ -253,7 +253,7 @@ public class EnumTest {
   }
 
   public EnumTest enumNumber(EnumNumberEnum enumNumber) {
-    this.enumNumber = Optional.of(enumNumber);
+    this.enumNumber = Optional.ofNullable(enumNumber);
     return this;
   }
 
@@ -273,7 +273,7 @@ public class EnumTest {
   }
 
   public EnumTest outerEnum(OuterEnum outerEnum) {
-    this.outerEnum = Optional.of(outerEnum);
+    this.outerEnum = Optional.ofNullable(outerEnum);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/File.java

@@ -27,7 +27,7 @@ public class File {
   private Optional<String> sourceURI = Optional.empty();
 
   public File sourceURI(String sourceURI) {
-    this.sourceURI = Optional.of(sourceURI);
+    this.sourceURI = Optional.ofNullable(sourceURI);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/FileSchemaTestClass.java

@@ -33,7 +33,7 @@ public class FileSchemaTestClass {
   private List<@Valid File> files = new ArrayList<>();
 
   public FileSchemaTestClass file(File file) {
-    this.file = Optional.of(file);
+    this.file = Optional.ofNullable(file);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/FormatTest.java

@@ -76,7 +76,7 @@ public class FormatTest {
   }
 
   public FormatTest integer(Integer integer) {
-    this.integer = Optional.of(integer);
+    this.integer = Optional.ofNullable(integer);
     return this;
   }
 
@@ -98,7 +98,7 @@ public class FormatTest {
   }
 
   public FormatTest int32(Integer int32) {
-    this.int32 = Optional.of(int32);
+    this.int32 = Optional.ofNullable(int32);
     return this;
   }
 
@@ -120,7 +120,7 @@ public class FormatTest {
   }
 
   public FormatTest int64(Long int64) {
-    this.int64 = Optional.of(int64);
+    this.int64 = Optional.ofNullable(int64);
     return this;
   }
 
@@ -162,7 +162,7 @@ public class FormatTest {
   }
 
   public FormatTest _float(Float _float) {
-    this._float = Optional.of(_float);
+    this._float = Optional.ofNullable(_float);
     return this;
   }
 
@@ -184,7 +184,7 @@ public class FormatTest {
   }
 
   public FormatTest _double(Double _double) {
-    this._double = Optional.of(_double);
+    this._double = Optional.ofNullable(_double);
     return this;
   }
 
@@ -206,7 +206,7 @@ public class FormatTest {
   }
 
   public FormatTest string(String string) {
-    this.string = Optional.of(string);
+    this.string = Optional.ofNullable(string);
     return this;
   }
 
@@ -246,7 +246,7 @@ public class FormatTest {
   }
 
   public FormatTest binary(org.springframework.core.io.Resource binary) {
-    this.binary = Optional.of(binary);
+    this.binary = Optional.ofNullable(binary);
     return this;
   }
 
@@ -286,7 +286,7 @@ public class FormatTest {
   }
 
   public FormatTest dateTime(OffsetDateTime dateTime) {
-    this.dateTime = Optional.of(dateTime);
+    this.dateTime = Optional.ofNullable(dateTime);
     return this;
   }
 
@@ -306,7 +306,7 @@ public class FormatTest {
   }
 
   public FormatTest uuid(UUID uuid) {
-    this.uuid = Optional.of(uuid);
+    this.uuid = Optional.ofNullable(uuid);
     return this;
   }
 
@@ -346,7 +346,7 @@ public class FormatTest {
   }
 
   public FormatTest bigDecimal(BigDecimal bigDecimal) {
-    this.bigDecimal = Optional.of(bigDecimal);
+    this.bigDecimal = Optional.ofNullable(bigDecimal);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/HasOnlyReadOnly.java

@@ -30,7 +30,7 @@ public class HasOnlyReadOnly {
   private Optional<String> foo = Optional.empty();
 
   public HasOnlyReadOnly bar(String bar) {
-    this.bar = Optional.of(bar);
+    this.bar = Optional.ofNullable(bar);
     return this;
   }
 
@@ -50,7 +50,7 @@ public class HasOnlyReadOnly {
   }
 
   public HasOnlyReadOnly foo(String foo) {
-    this.foo = Optional.of(foo);
+    this.foo = Optional.ofNullable(foo);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/MixedPropertiesAndAdditionalPropertiesClass.java

@@ -38,7 +38,7 @@ public class MixedPropertiesAndAdditionalPropertiesClass {
   private Map<String, Animal> map = new HashMap<>();
 
   public MixedPropertiesAndAdditionalPropertiesClass uuid(UUID uuid) {
-    this.uuid = Optional.of(uuid);
+    this.uuid = Optional.ofNullable(uuid);
     return this;
   }
 
@@ -58,7 +58,7 @@ public class MixedPropertiesAndAdditionalPropertiesClass {
   }
 
   public MixedPropertiesAndAdditionalPropertiesClass dateTime(OffsetDateTime dateTime) {
-    this.dateTime = Optional.of(dateTime);
+    this.dateTime = Optional.ofNullable(dateTime);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/Model200Response.java

@@ -31,7 +31,7 @@ public class Model200Response {
   private Optional<String> propertyClass = Optional.empty();
 
   public Model200Response name(Integer name) {
-    this.name = Optional.of(name);
+    this.name = Optional.ofNullable(name);
     return this;
   }
 
@@ -51,7 +51,7 @@ public class Model200Response {
   }
 
   public Model200Response propertyClass(String propertyClass) {
-    this.propertyClass = Optional.of(propertyClass);
+    this.propertyClass = Optional.ofNullable(propertyClass);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/ModelApiResponse.java

@@ -32,7 +32,7 @@ public class ModelApiResponse {
   private Optional<String> message = Optional.empty();
 
   public ModelApiResponse code(Integer code) {
-    this.code = Optional.of(code);
+    this.code = Optional.ofNullable(code);
     return this;
   }
 
@@ -52,7 +52,7 @@ public class ModelApiResponse {
   }
 
   public ModelApiResponse type(String type) {
-    this.type = Optional.of(type);
+    this.type = Optional.ofNullable(type);
     return this;
   }
 
@@ -72,7 +72,7 @@ public class ModelApiResponse {
   }
 
   public ModelApiResponse message(String message) {
-    this.message = Optional.of(message);
+    this.message = Optional.ofNullable(message);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/ModelList.java

@@ -28,7 +28,7 @@ public class ModelList {
   private Optional<String> _123list = Optional.empty();
 
   public ModelList _123list(String _123list) {
-    this._123list = Optional.of(_123list);
+    this._123list = Optional.ofNullable(_123list);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/ModelReturn.java

@@ -29,7 +29,7 @@ public class ModelReturn {
   private Optional<Integer> _return = Optional.empty();
 
   public ModelReturn _return(Integer _return) {
-    this._return = Optional.of(_return);
+    this._return = Optional.ofNullable(_return);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/Name.java

@@ -64,7 +64,7 @@ public class Name {
   }
 
   public Name snakeCase(Integer snakeCase) {
-    this.snakeCase = Optional.of(snakeCase);
+    this.snakeCase = Optional.ofNullable(snakeCase);
     return this;
   }
 
@@ -84,7 +84,7 @@ public class Name {
   }
 
   public Name property(String property) {
-    this.property = Optional.of(property);
+    this.property = Optional.ofNullable(property);
     return this;
   }
 
@@ -104,7 +104,7 @@ public class Name {
   }
 
   public Name _123number(Integer _123number) {
-    this._123number = Optional.of(_123number);
+    this._123number = Optional.ofNullable(_123number);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/NumberOnly.java

@@ -27,7 +27,7 @@ public class NumberOnly {
   private Optional<BigDecimal> justNumber = Optional.empty();
 
   public NumberOnly justNumber(BigDecimal justNumber) {
-    this.justNumber = Optional.of(justNumber);
+    this.justNumber = Optional.ofNullable(justNumber);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/Order.java

@@ -77,7 +77,7 @@ public class Order {
   private Optional<Boolean> complete = Optional.of(false);
 
   public Order id(Long id) {
-    this.id = Optional.of(id);
+    this.id = Optional.ofNullable(id);
     return this;
   }
 
@@ -97,7 +97,7 @@ public class Order {
   }
 
   public Order petId(Long petId) {
-    this.petId = Optional.of(petId);
+    this.petId = Optional.ofNullable(petId);
     return this;
   }
 
@@ -117,7 +117,7 @@ public class Order {
   }
 
   public Order quantity(Integer quantity) {
-    this.quantity = Optional.of(quantity);
+    this.quantity = Optional.ofNullable(quantity);
     return this;
   }
 
@@ -137,7 +137,7 @@ public class Order {
   }
 
   public Order shipDate(OffsetDateTime shipDate) {
-    this.shipDate = Optional.of(shipDate);
+    this.shipDate = Optional.ofNullable(shipDate);
     return this;
   }
 
@@ -157,7 +157,7 @@ public class Order {
   }
 
   public Order status(StatusEnum status) {
-    this.status = Optional.of(status);
+    this.status = Optional.ofNullable(status);
     return this;
   }
 
@@ -177,7 +177,7 @@ public class Order {
   }
 
   public Order complete(Boolean complete) {
-    this.complete = Optional.of(complete);
+    this.complete = Optional.ofNullable(complete);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/OuterComposite.java

@@ -31,7 +31,7 @@ public class OuterComposite {
   private Optional<Boolean> myBoolean = Optional.empty();
 
   public OuterComposite myNumber(BigDecimal myNumber) {
-    this.myNumber = Optional.of(myNumber);
+    this.myNumber = Optional.ofNullable(myNumber);
     return this;
   }
 
@@ -51,7 +51,7 @@ public class OuterComposite {
   }
 
   public OuterComposite myString(String myString) {
-    this.myString = Optional.of(myString);
+    this.myString = Optional.ofNullable(myString);
     return this;
   }
 
@@ -71,7 +71,7 @@ public class OuterComposite {
   }
 
   public OuterComposite myBoolean(Boolean myBoolean) {
-    this.myBoolean = Optional.of(myBoolean);
+    this.myBoolean = Optional.ofNullable(myBoolean);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/ParentWithNullable.java

@@ -77,7 +77,7 @@ public class ParentWithNullable {
   private JsonNullable<String> nullableProperty = JsonNullable.<String>undefined();
 
   public ParentWithNullable type(TypeEnum type) {
-    this.type = Optional.of(type);
+    this.type = Optional.ofNullable(type);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/Pet.java

@@ -97,7 +97,7 @@ public class Pet {
   }
 
   public Pet id(Long id) {
-    this.id = Optional.of(id);
+    this.id = Optional.ofNullable(id);
     return this;
   }
 
@@ -117,7 +117,7 @@ public class Pet {
   }
 
   public Pet category(Category category) {
-    this.category = Optional.of(category);
+    this.category = Optional.ofNullable(category);
     return this;
   }
 
@@ -214,7 +214,7 @@ public class Pet {
   }
 
   public Pet status(StatusEnum status) {
-    this.status = Optional.of(status);
+    this.status = Optional.ofNullable(status);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/ReadOnlyFirst.java

@@ -28,7 +28,7 @@ public class ReadOnlyFirst {
   private Optional<String> baz = Optional.empty();
 
   public ReadOnlyFirst bar(String bar) {
-    this.bar = Optional.of(bar);
+    this.bar = Optional.ofNullable(bar);
     return this;
   }
 
@@ -48,7 +48,7 @@ public class ReadOnlyFirst {
   }
 
   public ReadOnlyFirst baz(String baz) {
-    this.baz = Optional.of(baz);
+    this.baz = Optional.ofNullable(baz);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/ResponseObjectWithDifferentFieldNames.java

@@ -32,7 +32,7 @@ public class ResponseObjectWithDifferentFieldNames {
   private Optional<String> propertyNameWithSpaces = Optional.empty();
 
   public ResponseObjectWithDifferentFieldNames normalPropertyName(String normalPropertyName) {
-    this.normalPropertyName = Optional.of(normalPropertyName);
+    this.normalPropertyName = Optional.ofNullable(normalPropertyName);
     return this;
   }
 
@@ -52,7 +52,7 @@ public class ResponseObjectWithDifferentFieldNames {
   }
 
   public ResponseObjectWithDifferentFieldNames UPPER_CASE_PROPERTY_SNAKE(String UPPER_CASE_PROPERTY_SNAKE) {
-    this.UPPER_CASE_PROPERTY_SNAKE = Optional.of(UPPER_CASE_PROPERTY_SNAKE);
+    this.UPPER_CASE_PROPERTY_SNAKE = Optional.ofNullable(UPPER_CASE_PROPERTY_SNAKE);
     return this;
   }
 
@@ -72,7 +72,7 @@ public class ResponseObjectWithDifferentFieldNames {
   }
 
   public ResponseObjectWithDifferentFieldNames lowerCasePropertyDashes(String lowerCasePropertyDashes) {
-    this.lowerCasePropertyDashes = Optional.of(lowerCasePropertyDashes);
+    this.lowerCasePropertyDashes = Optional.ofNullable(lowerCasePropertyDashes);
     return this;
   }
 
@@ -92,7 +92,7 @@ public class ResponseObjectWithDifferentFieldNames {
   }
 
   public ResponseObjectWithDifferentFieldNames propertyNameWithSpaces(String propertyNameWithSpaces) {
-    this.propertyNameWithSpaces = Optional.of(propertyNameWithSpaces);
+    this.propertyNameWithSpaces = Optional.ofNullable(propertyNameWithSpaces);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/SpecialModelName.java

@@ -28,7 +28,7 @@ public class SpecialModelName {
   private Optional<Long> $specialPropertyName = Optional.empty();
 
   public SpecialModelName $specialPropertyName(Long $specialPropertyName) {
-    this.$specialPropertyName = Optional.of($specialPropertyName);
+    this.$specialPropertyName = Optional.ofNullable($specialPropertyName);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/Tag.java

@@ -28,7 +28,7 @@ public class Tag {
   private Optional<String> name = Optional.empty();
 
   public Tag id(Long id) {
-    this.id = Optional.of(id);
+    this.id = Optional.ofNullable(id);
     return this;
   }
 
@@ -48,7 +48,7 @@ public class Tag {
   }
 
   public Tag name(String name) {
-    this.name = Optional.of(name);
+    this.name = Optional.ofNullable(name);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/User.java

@@ -40,7 +40,7 @@ public class User {
   private Optional<Integer> userStatus = Optional.empty();
 
   public User id(Long id) {
-    this.id = Optional.of(id);
+    this.id = Optional.ofNullable(id);
     return this;
   }
 
@@ -60,7 +60,7 @@ public class User {
   }
 
   public User username(String username) {
-    this.username = Optional.of(username);
+    this.username = Optional.ofNullable(username);
     return this;
   }
 
@@ -80,7 +80,7 @@ public class User {
   }
 
   public User firstName(String firstName) {
-    this.firstName = Optional.of(firstName);
+    this.firstName = Optional.ofNullable(firstName);
     return this;
   }
 
@@ -100,7 +100,7 @@ public class User {
   }
 
   public User lastName(String lastName) {
-    this.lastName = Optional.of(lastName);
+    this.lastName = Optional.ofNullable(lastName);
     return this;
   }
 
@@ -120,7 +120,7 @@ public class User {
   }
 
   public User email(String email) {
-    this.email = Optional.of(email);
+    this.email = Optional.ofNullable(email);
     return this;
   }
 
@@ -140,7 +140,7 @@ public class User {
   }
 
   public User password(String password) {
-    this.password = Optional.of(password);
+    this.password = Optional.ofNullable(password);
     return this;
   }
 
@@ -160,7 +160,7 @@ public class User {
   }
 
   public User phone(String phone) {
-    this.phone = Optional.of(phone);
+    this.phone = Optional.ofNullable(phone);
     return this;
   }
 
@@ -180,7 +180,7 @@ public class User {
   }
 
   public User userStatus(Integer userStatus) {
-    this.userStatus = Optional.of(userStatus);
+    this.userStatus = Optional.ofNullable(userStatus);
     return this;
   }
 

samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/model/XmlItem.java

@@ -95,7 +95,7 @@ public class XmlItem {
   private List<Integer> prefixNsWrappedArray = new ArrayList<>();
 
   public XmlItem attributeString(String attributeString) {
-    this.attributeString = Optional.of(attributeString);
+    this.attributeString = Optional.ofNullable(attributeString);
     return this;
   }
 
@@ -115,7 +115,7 @@ public class XmlItem {
   }
 
   public XmlItem attributeNumber(BigDecimal attributeNumber) {
-    this.attributeNumber = Optional.of(attributeNumber);
+    this.attributeNumber = Optional.ofNullable(attributeNumber);
     return this;
   }
 
@@ -135,7 +135,7 @@ public class XmlItem {
   }
 
   public XmlItem attributeInteger(Integer attributeInteger) {
-    this.attributeInteger = Optional.of(attributeInteger);
+    this.attributeInteger = Optional.ofNullable(attributeInteger);
     return this;
   }
 
@@ -155,7 +155,7 @@ public class XmlItem {
   }
 
   public XmlItem attributeBoolean(Boolean attributeBoolean) {
-    this.attributeBoolean = Optional.of(attributeBoolean);
+    this.attributeBoolean = Optional.ofNullable(attributeBoolean);
     return this;
   }
 
@@ -203,7 +203,7 @@ public class XmlItem {
   }
 
   public XmlItem nameString(String nameString) {
-    this.nameString = Optional.of(nameString);
+    this.nameString = Optional.ofNullable(nameString);
     return this;
   }
 
@@ -223,7 +223,7 @@ public class XmlItem {
   }
 
   public XmlItem nameNumber(BigDecimal nameNumber) {
-    this.nameNumber = Optional.of(nameNumber);
+    this.nameNumber = Optional.ofNullable(nameNumber);
     return this;
   }
 
@@ -243,7 +243,7 @@ public class XmlItem {
   }
 
   public XmlItem nameInteger(Integer nameInteger) {
-    this.nameInteger = Optional.of(nameInteger);
+    this.nameInteger = Optional.ofNullable(nameInteger);
     return this;
   }
 
@@ -263,7 +263,7 @@ public class XmlItem {
   }
 
   public XmlItem nameBoolean(Boolean nameBoolean) {
-    this.nameBoolean = Optional.of(nameBoolean);
+    this.nameBoolean = Optional.ofNullable(nameBoolean);
     return this;
   }
 
@@ -339,7 +339,7 @@ public class XmlItem {
   }
 
   public XmlItem prefixString(String prefixString) {
-    this.prefixString = Optional.of(prefixString);
+    this.prefixString = Optional.ofNullable(prefixString);
     return this;
   }
 
@@ -359,7 +359,7 @@ public class XmlItem {
   }
 
   public XmlItem prefixNumber(BigDecimal prefixNumber) {
-    this.prefixNumber = Optional.of(prefixNumber);
+    this.prefixNumber = Optional.ofNullable(prefixNumber);
     return this;
   }
 
@@ -379,7 +379,7 @@ public class XmlItem {
   }
 
   public XmlItem prefixInteger(Integer prefixInteger) {
-    this.prefixInteger = Optional.of(prefixInteger);
+    this.prefixInteger = Optional.ofNullable(prefixInteger);
     return this;
   }
 
@@ -399,7 +399,7 @@ public class XmlItem {
   }
 
   public XmlItem prefixBoolean(Boolean prefixBoolean) {
-    this.prefixBoolean = Optional.of(prefixBoolean);
+    this.prefixBoolean = Optional.ofNullable(prefixBoolean);
     return this;
   }
 
@@ -475,7 +475,7 @@ public class XmlItem {
   }
 
   public XmlItem namespaceString(String namespaceString) {
-    this.namespaceString = Optional.of(namespaceString);
+    this.namespaceString = Optional.ofNullable(namespaceString);
     return this;
   }
 
@@ -495,7 +495,7 @@ public class XmlItem {
   }
 
   public XmlItem namespaceNumber(BigDecimal namespaceNumber) {
-    this.namespaceNumber = Optional.of(namespaceNumber);
+    this.namespaceNumber = Optional.ofNullable(namespaceNumber);
     return this;
   }
 
@@ -515,7 +515,7 @@ public class XmlItem {
   }
 
   public XmlItem namespaceInteger(Integer namespaceInteger) {
-    this.namespaceInteger = Optional.of(namespaceInteger);
+    this.namespaceInteger = Optional.ofNullable(namespaceInteger);
     return this;
   }
 
@@ -535,7 +535,7 @@ public class XmlItem {
   }
 
   public XmlItem namespaceBoolean(Boolean namespaceBoolean) {
-    this.namespaceBoolean = Optional.of(namespaceBoolean);
+    this.namespaceBoolean = Optional.ofNullable(namespaceBoolean);
     return this;
   }
 
@@ -611,7 +611,7 @@ public class XmlItem {
   }
 
   public XmlItem prefixNsString(String prefixNsString) {
-    this.prefixNsString = Optional.of(prefixNsString);
+    this.prefixNsString = Optional.ofNullable(prefixNsString);
     return this;
   }
 
@@ -631,7 +631,7 @@ public class XmlItem {
   }
 
   public XmlItem prefixNsNumber(BigDecimal prefixNsNumber) {
-    this.prefixNsNumber = Optional.of(prefixNsNumber);
+    this.prefixNsNumber = Optional.ofNullable(prefixNsNumber);
     return this;
   }
 
@@ -651,7 +651,7 @@ public class XmlItem {
   }
 
   public XmlItem prefixNsInteger(Integer prefixNsInteger) {
-    this.prefixNsInteger = Optional.of(prefixNsInteger);
+    this.prefixNsInteger = Optional.ofNullable(prefixNsInteger);
     return this;
   }
 
@@ -671,7 +671,7 @@ public class XmlItem {
   }
 
   public XmlItem prefixNsBoolean(Boolean prefixNsBoolean) {
-    this.prefixNsBoolean = Optional.of(prefixNsBoolean);
+    this.prefixNsBoolean = Optional.ofNullable(prefixNsBoolean);
     return this;
   }