[java] fix optional array property's default value (#14961)

* fix optional array property default value

* fix default values

* more fixes

* update default value for jersey2, 3, okhttp-gson

* update default value

* fix java okhttp-gson

* fix jersey2, 3

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

@@ -50,6 +50,9 @@ public class AdditionalPropertiesClass {
   }
 
   public AdditionalPropertiesClass putMapPropertyItem(String key, String mapPropertyItem) {
+    if (this.mapProperty == null) {
+      this.mapProperty = new HashMap<>();
+    }
     this.mapProperty.put(key, mapPropertyItem);
     return this;
   }
@@ -81,6 +84,9 @@ public class AdditionalPropertiesClass {
   }
 
   public AdditionalPropertiesClass putMapOfMapPropertyItem(String key, Map<String, String> mapOfMapPropertyItem) {
+    if (this.mapOfMapProperty == null) {
+      this.mapOfMapProperty = new HashMap<>();
+    }
     this.mapOfMapProperty.put(key, mapOfMapPropertyItem);
     return this;
   }

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

@@ -47,6 +47,9 @@ public class ArrayOfArrayOfNumberOnly {
   }
 
   public ArrayOfArrayOfNumberOnly addArrayArrayNumberItem(List<BigDecimal> arrayArrayNumberItem) {
+    if (this.arrayArrayNumber == null) {
+      this.arrayArrayNumber = new ArrayList<>();
+    }
     this.arrayArrayNumber.add(arrayArrayNumberItem);
     return this;
   }

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

@@ -47,6 +47,9 @@ public class ArrayOfNumberOnly {
   }
 
   public ArrayOfNumberOnly addArrayNumberItem(BigDecimal arrayNumberItem) {
+    if (this.arrayNumber == null) {
+      this.arrayNumber = new ArrayList<>();
+    }
     this.arrayNumber.add(arrayNumberItem);
     return this;
   }

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

@@ -55,6 +55,9 @@ public class ArrayTest {
   }
 
   public ArrayTest addArrayOfStringItem(String arrayOfStringItem) {
+    if (this.arrayOfString == null) {
+      this.arrayOfString = new ArrayList<>();
+    }
     this.arrayOfString.add(arrayOfStringItem);
     return this;
   }
@@ -86,6 +89,9 @@ public class ArrayTest {
   }
 
   public ArrayTest addArrayArrayOfIntegerItem(List<Long> arrayArrayOfIntegerItem) {
+    if (this.arrayArrayOfInteger == null) {
+      this.arrayArrayOfInteger = new ArrayList<>();
+    }
     this.arrayArrayOfInteger.add(arrayArrayOfIntegerItem);
     return this;
   }
@@ -117,6 +123,9 @@ public class ArrayTest {
   }
 
   public ArrayTest addArrayArrayOfModelItem(List<ReadOnlyFirst> arrayArrayOfModelItem) {
+    if (this.arrayArrayOfModel == null) {
+      this.arrayArrayOfModel = new ArrayList<>();
+    }
     this.arrayArrayOfModel.add(arrayArrayOfModelItem);
     return this;
   }

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

@@ -146,6 +146,9 @@ public class EnumArrays {
   }
 
   public EnumArrays addArrayEnumItem(ArrayEnumEnum arrayEnumItem) {
+    if (this.arrayEnum == null) {
+      this.arrayEnum = new ArrayList<>();
+    }
     this.arrayEnum.add(arrayEnumItem);
     return this;
   }

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

@@ -77,6 +77,9 @@ public class FileSchemaTestClass {
   }
 
   public FileSchemaTestClass addFilesItem(ModelFile filesItem) {
+    if (this.files == null) {
+      this.files = new ArrayList<>();
+    }
     this.files.add(filesItem);
     return this;
   }

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

@@ -93,6 +93,9 @@ public class MapTest {
   }
 
   public MapTest putMapMapOfStringItem(String key, Map<String, String> mapMapOfStringItem) {
+    if (this.mapMapOfString == null) {
+      this.mapMapOfString = new HashMap<>();
+    }
     this.mapMapOfString.put(key, mapMapOfStringItem);
     return this;
   }
@@ -124,6 +127,9 @@ public class MapTest {
   }
 
   public MapTest putMapOfEnumStringItem(String key, InnerEnum mapOfEnumStringItem) {
+    if (this.mapOfEnumString == null) {
+      this.mapOfEnumString = new HashMap<>();
+    }
     this.mapOfEnumString.put(key, mapOfEnumStringItem);
     return this;
   }
@@ -155,6 +161,9 @@ public class MapTest {
   }
 
   public MapTest putDirectMapItem(String key, Boolean directMapItem) {
+    if (this.directMap == null) {
+      this.directMap = new HashMap<>();
+    }
     this.directMap.put(key, directMapItem);
     return this;
   }
@@ -186,6 +195,9 @@ public class MapTest {
   }
 
   public MapTest putIndirectMapItem(String key, Boolean indirectMapItem) {
+    if (this.indirectMap == null) {
+      this.indirectMap = new HashMap<>();
+    }
     this.indirectMap.put(key, indirectMapItem);
     return this;
   }

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

@@ -109,6 +109,9 @@ public class MixedPropertiesAndAdditionalPropertiesClass {
   }
 
   public MixedPropertiesAndAdditionalPropertiesClass putMapItem(String key, Animal mapItem) {
+    if (this.map == null) {
+      this.map = new HashMap<>();
+    }
     this.map.put(key, mapItem);
     return this;
   }

samples/client/petstore/java/webclient/src/main/java/org/openapitools/client/model/NullableClass.java

@@ -396,6 +396,9 @@ public class NullableClass extends HashMap<String, Object> {
   }
 
   public NullableClass addArrayItemsNullableItem(Object arrayItemsNullableItem) {
+    if (this.arrayItemsNullable == null) {
+      this.arrayItemsNullable = new ArrayList<>();
+    }
     this.arrayItemsNullable.add(arrayItemsNullableItem);
     return this;
   }
@@ -519,6 +522,9 @@ public class NullableClass extends HashMap<String, Object> {
   }
 
   public NullableClass putObjectItemsNullableItem(String key, Object objectItemsNullableItem) {
+    if (this.objectItemsNullable == null) {
+      this.objectItemsNullable = new HashMap<>();
+    }
     this.objectItemsNullable.put(key, objectItemsNullableItem);
     return this;
   }

samples/client/petstore/java/webclient/src/main/java/org/openapitools/client/model/ObjectWithDeprecatedFields.java

@@ -142,6 +142,9 @@ public class ObjectWithDeprecatedFields {
   }
 
   public ObjectWithDeprecatedFields addBarsItem(String barsItem) {
+    if (this.bars == null) {
+      this.bars = new ArrayList<>();
+    }
     this.bars.add(barsItem);
     return this;
   }

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

@@ -186,6 +186,9 @@ public class Pet {
   }
 
   public Pet addPhotoUrlsItem(String photoUrlsItem) {
+    if (this.photoUrls == null) {
+      this.photoUrls = new LinkedHashSet<>();
+    }
     this.photoUrls.add(photoUrlsItem);
     return this;
   }
@@ -218,6 +221,9 @@ public class Pet {
   }
 
   public Pet addTagsItem(Tag tagsItem) {
+    if (this.tags == null) {
+      this.tags = new ArrayList<>();
+    }
     this.tags.add(tagsItem);
     return this;
   }