[Java] better default value handling (#14130)

* add test for array default value

* update null return

* minor fixes

* move default value tests to echo api spec

* add new files

* remove unused files

* fix enum array default, add tests

* better array init

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

Co-authored-by: Leonard Brünings <lord_damokles@gmx.net>

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

Co-authored-by: Leonard Brünings <lord_damokles@gmx.net>

* revert the fix

* improve default value handling

* update native samples, add tests

* update samples

* fix tests

* use conditional test for timezone

* add tests to apache http client echo api

* add option to default container to null

* fix map default value

* minor refactoring

* update samples

* fix javadoc

* fix pom.xml

* add tests in java native echo client

* add java apache client echo tests

* fix test

* fix test

---------

Co-authored-by: Leonard Brünings <lord_damokles@gmx.net>

samples/client/petstore/java/native/docs/ArrayDefaultValue.md

@@ -0,0 +1,24 @@
+
+
+# ArrayDefaultValue
+
+
+## Properties
+
+| Name | Type | Description | Notes |
+|------------ | ------------- | ------------- | -------------|
+|**id** | **Long** | id |  [optional] |
+|**outcomes** | [**List<OutcomesEnum>**](#List<OutcomesEnum>) |  |  [optional] |
+
+
+
+## Enum: List<OutcomesEnum>
+
+| Name | Value |
+|---- | -----|
+| SUCCESS | "SUCCESS" |
+| FAILURE | "FAILURE" |
+| SKIPPED | "SKIPPED" |
+
+
+

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

@@ -50,10 +50,10 @@ import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 @javax.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen")
 public class AdditionalPropertiesClass {
   public static final String JSON_PROPERTY_MAP_PROPERTY = "map_property";
-  private Map<String, String> mapProperty = null;
+  private Map<String, String> mapProperty = new HashMap<>();
 
   public static final String JSON_PROPERTY_MAP_OF_MAP_PROPERTY = "map_of_map_property";
-  private Map<String, Map<String, String>> mapOfMapProperty = null;
+  private Map<String, Map<String, String>> mapOfMapProperty = new HashMap<>();
 
   public static final String JSON_PROPERTY_ANYTYPE1 = "anytype_1";
   private JsonNullable<Object> anytype1 = JsonNullable.<Object>of(null);
@@ -65,13 +65,13 @@ public class AdditionalPropertiesClass {
   private Object mapWithUndeclaredPropertiesAnytype2;
 
   public static final String JSON_PROPERTY_MAP_WITH_UNDECLARED_PROPERTIES_ANYTYPE3 = "map_with_undeclared_properties_anytype_3";
-  private Map<String, Object> mapWithUndeclaredPropertiesAnytype3 = null;
+  private Map<String, Object> mapWithUndeclaredPropertiesAnytype3 = new HashMap<>();
 
   public static final String JSON_PROPERTY_EMPTY_MAP = "empty_map";
   private Object emptyMap;
 
   public static final String JSON_PROPERTY_MAP_WITH_UNDECLARED_PROPERTIES_STRING = "map_with_undeclared_properties_string";
-  private Map<String, String> mapWithUndeclaredPropertiesString = null;
+  private Map<String, String> mapWithUndeclaredPropertiesString = new HashMap<>();
 
   public AdditionalPropertiesClass() { 
   }

samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ArrayDefaultValue.java

@@ -0,0 +1,186 @@
+/*
+ * OpenAPI Petstore
+ * This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.model;
+
+import java.util.Objects;
+import java.util.Arrays;
+import java.util.Map;
+import java.util.HashMap;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonValue;
+import java.util.ArrayList;
+import java.util.List;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+
+
+/**
+ * ArrayDefaultValue
+ */
+@JsonPropertyOrder({
+  ArrayDefaultValue.JSON_PROPERTY_ID,
+  ArrayDefaultValue.JSON_PROPERTY_OUTCOMES
+})
+@javax.annotation.processing.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen")
+public class ArrayDefaultValue {
+  public static final String JSON_PROPERTY_ID = "id";
+  private Long id;
+
+  /**
+   * Gets or Sets outcomes
+   */
+  public enum OutcomesEnum {
+    SUCCESS("SUCCESS"),
+    
+    FAILURE("FAILURE"),
+    
+    SKIPPED("SKIPPED");
+
+    private String value;
+
+    OutcomesEnum(String value) {
+      this.value = value;
+    }
+
+    @JsonValue
+    public String getValue() {
+      return value;
+    }
+
+    @Override
+    public String toString() {
+      return String.valueOf(value);
+    }
+
+    @JsonCreator
+    public static OutcomesEnum fromValue(String value) {
+      for (OutcomesEnum b : OutcomesEnum.values()) {
+        if (b.value.equals(value)) {
+          return b;
+        }
+      }
+      throw new IllegalArgumentException("Unexpected value '" + value + "'");
+    }
+  }
+
+  public static final String JSON_PROPERTY_OUTCOMES = "outcomes";
+  private List<OutcomesEnum> outcomes = null;
+
+  public ArrayDefaultValue() { 
+  }
+
+  public ArrayDefaultValue id(Long id) {
+    this.id = id;
+    return this;
+  }
+
+   /**
+   * id
+   * @return id
+  **/
+  @javax.annotation.Nullable
+  @JsonProperty(JSON_PROPERTY_ID)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
+  public Long getId() {
+    return id;
+  }
+
+
+  @JsonProperty(JSON_PROPERTY_ID)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+  public void setId(Long id) {
+    this.id = id;
+  }
+
+
+  public ArrayDefaultValue outcomes(List<OutcomesEnum> outcomes) {
+    this.outcomes = outcomes;
+    return this;
+  }
+
+  public ArrayDefaultValue addOutcomesItem(OutcomesEnum outcomesItem) {
+    if (this.outcomes == null) {
+      this.outcomes = new ArrayList<>();
+    }
+    this.outcomes.add(outcomesItem);
+    return this;
+  }
+
+   /**
+   * Get outcomes
+   * @return outcomes
+  **/
+  @javax.annotation.Nullable
+  @JsonProperty(JSON_PROPERTY_OUTCOMES)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+
+  public List<OutcomesEnum> getOutcomes() {
+    return outcomes;
+  }
+
+
+  @JsonProperty(JSON_PROPERTY_OUTCOMES)
+  @JsonInclude(value = JsonInclude.Include.USE_DEFAULTS)
+  public void setOutcomes(List<OutcomesEnum> outcomes) {
+    this.outcomes = outcomes;
+  }
+
+
+  /**
+   * Return true if this ArrayDefaultValue object is equal to o.
+   */
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+    ArrayDefaultValue arrayDefaultValue = (ArrayDefaultValue) o;
+    return Objects.equals(this.id, arrayDefaultValue.id) &&
+        Objects.equals(this.outcomes, arrayDefaultValue.outcomes);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(id, outcomes);
+  }
+
+  @Override
+  public String toString() {
+    StringBuilder sb = new StringBuilder();
+    sb.append("class ArrayDefaultValue {\n");
+    sb.append("    id: ").append(toIndentedString(id)).append("\n");
+    sb.append("    outcomes: ").append(toIndentedString(outcomes)).append("\n");
+    sb.append("}");
+    return sb.toString();
+  }
+
+  /**
+   * Convert the given object to string with each line indented by 4 spaces
+   * (except the first line).
+   */
+  private String toIndentedString(Object o) {
+    if (o == null) {
+      return "null";
+    }
+    return o.toString().replace("\n", "\n    ");
+  }
+
+}
+

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

@@ -40,7 +40,7 @@ import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 @javax.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen")
 public class ArrayOfArrayOfNumberOnly {
   public static final String JSON_PROPERTY_ARRAY_ARRAY_NUMBER = "ArrayArrayNumber";
-  private List<List<BigDecimal>> arrayArrayNumber = null;
+  private List<List<BigDecimal>> arrayArrayNumber = new ArrayList<>();
 
   public ArrayOfArrayOfNumberOnly() { 
   }

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

@@ -40,7 +40,7 @@ import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 @javax.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen")
 public class ArrayOfNumberOnly {
   public static final String JSON_PROPERTY_ARRAY_NUMBER = "ArrayNumber";
-  private List<BigDecimal> arrayNumber = null;
+  private List<BigDecimal> arrayNumber = new ArrayList<>();
 
   public ArrayOfNumberOnly() { 
   }

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

@@ -42,13 +42,13 @@ import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 @javax.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen")
 public class ArrayTest {
   public static final String JSON_PROPERTY_ARRAY_OF_STRING = "array_of_string";
-  private List<String> arrayOfString = null;
+  private List<String> arrayOfString = new ArrayList<>();
 
   public static final String JSON_PROPERTY_ARRAY_ARRAY_OF_INTEGER = "array_array_of_integer";
-  private List<List<Long>> arrayArrayOfInteger = null;
+  private List<List<Long>> arrayArrayOfInteger = new ArrayList<>();
 
   public static final String JSON_PROPERTY_ARRAY_ARRAY_OF_MODEL = "array_array_of_model";
-  private List<List<ReadOnlyFirst>> arrayArrayOfModel = null;
+  private List<List<ReadOnlyFirst>> arrayArrayOfModel = new ArrayList<>();
 
   public ArrayTest() { 
   }

samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Drawing.java

@@ -65,7 +65,7 @@ public class Drawing extends HashMap<String, Fruit> {
   private JsonNullable<NullableShape> nullableShape = JsonNullable.<NullableShape>undefined();
 
   public static final String JSON_PROPERTY_SHAPES = "shapes";
-  private List<Shape> shapes = null;
+  private List<Shape> shapes = new ArrayList<>();
 
   public Drawing() { 
   }

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

@@ -113,7 +113,7 @@ public class EnumArrays {
   }
 
   public static final String JSON_PROPERTY_ARRAY_ENUM = "array_enum";
-  private List<ArrayEnumEnum> arrayEnum = null;
+  private List<ArrayEnumEnum> arrayEnum = new ArrayList<>();
 
   public EnumArrays() { 
   }

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

@@ -44,7 +44,7 @@ public class FileSchemaTestClass {
   private ModelFile _file;
 
   public static final String JSON_PROPERTY_FILES = "files";
-  private List<ModelFile> files = null;
+  private List<ModelFile> files = new ArrayList<>();
 
   public FileSchemaTestClass() { 
   }

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

@@ -42,7 +42,7 @@ import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 @javax.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen")
 public class MapTest {
   public static final String JSON_PROPERTY_MAP_MAP_OF_STRING = "map_map_of_string";
-  private Map<String, Map<String, String>> mapMapOfString = null;
+  private Map<String, Map<String, String>> mapMapOfString = new HashMap<>();
 
   /**
    * Gets or Sets inner
@@ -80,13 +80,13 @@ public class MapTest {
   }
 
   public static final String JSON_PROPERTY_MAP_OF_ENUM_STRING = "map_of_enum_string";
-  private Map<String, InnerEnum> mapOfEnumString = null;
+  private Map<String, InnerEnum> mapOfEnumString = new HashMap<>();
 
   public static final String JSON_PROPERTY_DIRECT_MAP = "direct_map";
-  private Map<String, Boolean> directMap = null;
+  private Map<String, Boolean> directMap = new HashMap<>();
 
   public static final String JSON_PROPERTY_INDIRECT_MAP = "indirect_map";
-  private Map<String, Boolean> indirectMap = null;
+  private Map<String, Boolean> indirectMap = new HashMap<>();
 
   public MapTest() { 
   }

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

@@ -50,7 +50,7 @@ public class MixedPropertiesAndAdditionalPropertiesClass {
   private OffsetDateTime dateTime;
 
   public static final String JSON_PROPERTY_MAP = "map";
-  private Map<String, Animal> map = null;
+  private Map<String, Animal> map = new HashMap<>();
 
   public MixedPropertiesAndAdditionalPropertiesClass() { 
   }

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

@@ -87,7 +87,7 @@ public class NullableClass extends HashMap<String, Object> {
   private JsonNullable<List<Object>> arrayAndItemsNullableProp = JsonNullable.<List<Object>>undefined();
 
   public static final String JSON_PROPERTY_ARRAY_ITEMS_NULLABLE = "array_items_nullable";
-  private List<Object> arrayItemsNullable = null;
+  private List<Object> arrayItemsNullable = new ArrayList<>();
 
   public static final String JSON_PROPERTY_OBJECT_NULLABLE_PROP = "object_nullable_prop";
   private JsonNullable<Map<String, Object>> objectNullableProp = JsonNullable.<Map<String, Object>>undefined();
@@ -96,7 +96,7 @@ public class NullableClass extends HashMap<String, Object> {
   private JsonNullable<Map<String, Object>> objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>undefined();
 
   public static final String JSON_PROPERTY_OBJECT_ITEMS_NULLABLE = "object_items_nullable";
-  private Map<String, Object> objectItemsNullable = null;
+  private Map<String, Object> objectItemsNullable = new HashMap<>();
 
   public NullableClass() { 
   }
@@ -306,7 +306,7 @@ public class NullableClass extends HashMap<String, Object> {
 
   public NullableClass addArrayNullablePropItem(Object arrayNullablePropItem) {
     if (this.arrayNullableProp == null || !this.arrayNullableProp.isPresent()) {
-      this.arrayNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
+      this.arrayNullableProp = JsonNullable.<List<Object>>of(null);
     }
     try {
       this.arrayNullableProp.get().add(arrayNullablePropItem);
@@ -351,7 +351,7 @@ public class NullableClass extends HashMap<String, Object> {
 
   public NullableClass addArrayAndItemsNullablePropItem(Object arrayAndItemsNullablePropItem) {
     if (this.arrayAndItemsNullableProp == null || !this.arrayAndItemsNullableProp.isPresent()) {
-      this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(new ArrayList<>());
+      this.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(null);
     }
     try {
       this.arrayAndItemsNullableProp.get().add(arrayAndItemsNullablePropItem);
@@ -429,7 +429,7 @@ public class NullableClass extends HashMap<String, Object> {
 
   public NullableClass putObjectNullablePropItem(String key, Object objectNullablePropItem) {
     if (this.objectNullableProp == null || !this.objectNullableProp.isPresent()) {
-      this.objectNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
+      this.objectNullableProp = JsonNullable.<Map<String, Object>>of(null);
     }
     try {
       this.objectNullableProp.get().put(key, objectNullablePropItem);
@@ -474,7 +474,7 @@ public class NullableClass extends HashMap<String, Object> {
 
   public NullableClass putObjectAndItemsNullablePropItem(String key, Object objectAndItemsNullablePropItem) {
     if (this.objectAndItemsNullableProp == null || !this.objectAndItemsNullableProp.isPresent()) {
-      this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(new HashMap<>());
+      this.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(null);
     }
     try {
       this.objectAndItemsNullableProp.get().put(key, objectAndItemsNullablePropItem);

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

@@ -53,7 +53,7 @@ public class ObjectWithDeprecatedFields {
   private DeprecatedObject deprecatedRef;
 
   public static final String JSON_PROPERTY_BARS = "bars";
-  private List<String> bars = null;
+  private List<String> bars = new ArrayList<>();
 
   public ObjectWithDeprecatedFields() { 
   }

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

@@ -58,7 +58,7 @@ public class Pet {
   private List<String> photoUrls = new ArrayList<>();
 
   public static final String JSON_PROPERTY_TAGS = "tags";
-  private List<Tag> tags = null;
+  private List<Tag> tags = new ArrayList<>();
 
   /**
    * pet status in the store

samples/client/petstore/java/native/src/test/java/org/openapitools/client/model/ArrayDefaultValueTest.java

@@ -0,0 +1,58 @@
+/*
+ * OpenAPI Petstore
+ * This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\
+ *
+ * The version of the OpenAPI document: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.model;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+import com.fasterxml.jackson.annotation.JsonValue;
+import java.util.ArrayList;
+import java.util.List;
+import org.junit.Assert;
+import org.junit.Ignore;
+import org.junit.Test;
+
+
+/**
+ * Model tests for ArrayDefaultValue
+ */
+public class ArrayDefaultValueTest {
+    private final ArrayDefaultValue model = new ArrayDefaultValue();
+
+    /**
+     * Model tests for ArrayDefaultValue
+     */
+    @Test
+    public void testArrayDefaultValue() {
+        // TODO: test ArrayDefaultValue
+    }
+
+    /**
+     * Test the property 'id'
+     */
+    @Test
+    public void idTest() {
+        // TODO: test id
+    }
+
+    /**
+     * Test the property 'outcomes'
+     */
+    @Test
+    public void outcomesTest() {
+        // TODO: test outcomes
+    }
+
+}