[java] implement #18032 add builder pattern to java client and spring generator (#18650)

* add builder pattern to java client and spring generator

* regenerate samples

* update doc

---------

Co-authored-by: jpfinne <jeanpaul@finne.be>

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

@@ -471,5 +471,98 @@ public class AdditionalPropertiesClass {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private AdditionalPropertiesClass instance;
+
+    public Builder() {
+      this(new AdditionalPropertiesClass());
+    }
+
+    protected Builder(AdditionalPropertiesClass instance) {
+      this.instance = instance;
+    }
+
+    public AdditionalPropertiesClass.Builder mapProperty(Map<String, String> mapProperty) {
+      this.instance.mapProperty = mapProperty;
+      return this;
+    }
+    public AdditionalPropertiesClass.Builder mapOfMapProperty(Map<String, Map<String, String>> mapOfMapProperty) {
+      this.instance.mapOfMapProperty = mapOfMapProperty;
+      return this;
+    }
+    public AdditionalPropertiesClass.Builder anytype1(Object anytype1) {
+      this.instance.anytype1 = JsonNullable.<Object>of(anytype1);
+      return this;
+    }
+    public AdditionalPropertiesClass.Builder anytype1(JsonNullable<Object> anytype1) {
+      this.instance.anytype1 = anytype1;
+      return this;
+    }
+    public AdditionalPropertiesClass.Builder mapWithUndeclaredPropertiesAnytype1(Object mapWithUndeclaredPropertiesAnytype1) {
+      this.instance.mapWithUndeclaredPropertiesAnytype1 = mapWithUndeclaredPropertiesAnytype1;
+      return this;
+    }
+    public AdditionalPropertiesClass.Builder mapWithUndeclaredPropertiesAnytype2(Object mapWithUndeclaredPropertiesAnytype2) {
+      this.instance.mapWithUndeclaredPropertiesAnytype2 = mapWithUndeclaredPropertiesAnytype2;
+      return this;
+    }
+    public AdditionalPropertiesClass.Builder mapWithUndeclaredPropertiesAnytype3(Map<String, Object> mapWithUndeclaredPropertiesAnytype3) {
+      this.instance.mapWithUndeclaredPropertiesAnytype3 = mapWithUndeclaredPropertiesAnytype3;
+      return this;
+    }
+    public AdditionalPropertiesClass.Builder emptyMap(Object emptyMap) {
+      this.instance.emptyMap = emptyMap;
+      return this;
+    }
+    public AdditionalPropertiesClass.Builder mapWithUndeclaredPropertiesString(Map<String, String> mapWithUndeclaredPropertiesString) {
+      this.instance.mapWithUndeclaredPropertiesString = mapWithUndeclaredPropertiesString;
+      return this;
+    }
+
+
+    /**
+    * returns a built AdditionalPropertiesClass instance.
+    *
+    * The builder is not reusable.
+    */
+    public AdditionalPropertiesClass build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static AdditionalPropertiesClass.Builder builder() {
+    return new AdditionalPropertiesClass.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public AdditionalPropertiesClass.Builder toBuilder() {
+    return new AdditionalPropertiesClass.Builder()
+      .mapProperty(getMapProperty())
+      .mapOfMapProperty(getMapOfMapProperty())
+      .anytype1(getAnytype1())
+      .mapWithUndeclaredPropertiesAnytype1(getMapWithUndeclaredPropertiesAnytype1())
+      .mapWithUndeclaredPropertiesAnytype2(getMapWithUndeclaredPropertiesAnytype2())
+      .mapWithUndeclaredPropertiesAnytype3(getMapWithUndeclaredPropertiesAnytype3())
+      .emptyMap(getEmptyMap())
+      .mapWithUndeclaredPropertiesString(getMapWithUndeclaredPropertiesString());
+  }
+
 }
 

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

@@ -204,5 +204,64 @@ static {
   mappings.put("Animal", Animal.class);
   JSON.registerDiscriminator(Animal.class, "className", mappings);
 }
+
+    public static class Builder {
+
+    private Animal instance;
+
+    public Builder() {
+      this(new Animal());
+    }
+
+    protected Builder(Animal instance) {
+      this.instance = instance;
+    }
+
+    public Animal.Builder className(String className) {
+      this.instance.className = className;
+      return this;
+    }
+    public Animal.Builder color(String color) {
+      this.instance.color = color;
+      return this;
+    }
+
+
+    /**
+    * returns a built Animal instance.
+    *
+    * The builder is not reusable.
+    */
+    public Animal build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static Animal.Builder builder() {
+    return new Animal.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public Animal.Builder toBuilder() {
+    return new Animal.Builder()
+      .className(getClassName())
+      .color(getColor());
+  }
+
 }
 

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

@@ -182,5 +182,64 @@ public class Apple {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private Apple instance;
+
+    public Builder() {
+      this(new Apple());
+    }
+
+    protected Builder(Apple instance) {
+      this.instance = instance;
+    }
+
+    public Apple.Builder cultivar(String cultivar) {
+      this.instance.cultivar = cultivar;
+      return this;
+    }
+    public Apple.Builder origin(String origin) {
+      this.instance.origin = origin;
+      return this;
+    }
+
+
+    /**
+    * returns a built Apple instance.
+    *
+    * The builder is not reusable.
+    */
+    public Apple build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static Apple.Builder builder() {
+    return new Apple.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public Apple.Builder toBuilder() {
+    return new Apple.Builder()
+      .cultivar(getCultivar())
+      .origin(getOrigin());
+  }
+
 }
 

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

@@ -182,5 +182,64 @@ public class AppleReq {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private AppleReq instance;
+
+    public Builder() {
+      this(new AppleReq());
+    }
+
+    protected Builder(AppleReq instance) {
+      this.instance = instance;
+    }
+
+    public AppleReq.Builder cultivar(String cultivar) {
+      this.instance.cultivar = cultivar;
+      return this;
+    }
+    public AppleReq.Builder mealy(Boolean mealy) {
+      this.instance.mealy = mealy;
+      return this;
+    }
+
+
+    /**
+    * returns a built AppleReq instance.
+    *
+    * The builder is not reusable.
+    */
+    public AppleReq build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static AppleReq.Builder builder() {
+    return new AppleReq.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public AppleReq.Builder toBuilder() {
+    return new AppleReq.Builder()
+      .cultivar(getCultivar())
+      .mealy(getMealy());
+  }
+
 }
 

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

@@ -163,5 +163,59 @@ public class ArrayOfArrayOfNumberOnly {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private ArrayOfArrayOfNumberOnly instance;
+
+    public Builder() {
+      this(new ArrayOfArrayOfNumberOnly());
+    }
+
+    protected Builder(ArrayOfArrayOfNumberOnly instance) {
+      this.instance = instance;
+    }
+
+    public ArrayOfArrayOfNumberOnly.Builder arrayArrayNumber(List<List<BigDecimal>> arrayArrayNumber) {
+      this.instance.arrayArrayNumber = arrayArrayNumber;
+      return this;
+    }
+
+
+    /**
+    * returns a built ArrayOfArrayOfNumberOnly instance.
+    *
+    * The builder is not reusable.
+    */
+    public ArrayOfArrayOfNumberOnly build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static ArrayOfArrayOfNumberOnly.Builder builder() {
+    return new ArrayOfArrayOfNumberOnly.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public ArrayOfArrayOfNumberOnly.Builder toBuilder() {
+    return new ArrayOfArrayOfNumberOnly.Builder()
+      .arrayArrayNumber(getArrayArrayNumber());
+  }
+
 }
 

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

@@ -163,5 +163,59 @@ public class ArrayOfNumberOnly {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private ArrayOfNumberOnly instance;
+
+    public Builder() {
+      this(new ArrayOfNumberOnly());
+    }
+
+    protected Builder(ArrayOfNumberOnly instance) {
+      this.instance = instance;
+    }
+
+    public ArrayOfNumberOnly.Builder arrayNumber(List<BigDecimal> arrayNumber) {
+      this.instance.arrayNumber = arrayNumber;
+      return this;
+    }
+
+
+    /**
+    * returns a built ArrayOfNumberOnly instance.
+    *
+    * The builder is not reusable.
+    */
+    public ArrayOfNumberOnly build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static ArrayOfNumberOnly.Builder builder() {
+    return new ArrayOfNumberOnly.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public ArrayOfNumberOnly.Builder toBuilder() {
+    return new ArrayOfNumberOnly.Builder()
+      .arrayNumber(getArrayNumber());
+  }
+
 }
 

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

@@ -259,5 +259,69 @@ public class ArrayTest {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private ArrayTest instance;
+
+    public Builder() {
+      this(new ArrayTest());
+    }
+
+    protected Builder(ArrayTest instance) {
+      this.instance = instance;
+    }
+
+    public ArrayTest.Builder arrayOfString(List<String> arrayOfString) {
+      this.instance.arrayOfString = arrayOfString;
+      return this;
+    }
+    public ArrayTest.Builder arrayArrayOfInteger(List<List<Long>> arrayArrayOfInteger) {
+      this.instance.arrayArrayOfInteger = arrayArrayOfInteger;
+      return this;
+    }
+    public ArrayTest.Builder arrayArrayOfModel(List<List<ReadOnlyFirst>> arrayArrayOfModel) {
+      this.instance.arrayArrayOfModel = arrayArrayOfModel;
+      return this;
+    }
+
+
+    /**
+    * returns a built ArrayTest instance.
+    *
+    * The builder is not reusable.
+    */
+    public ArrayTest build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static ArrayTest.Builder builder() {
+    return new ArrayTest.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public ArrayTest.Builder toBuilder() {
+    return new ArrayTest.Builder()
+      .arrayOfString(getArrayOfString())
+      .arrayArrayOfInteger(getArrayArrayOfInteger())
+      .arrayArrayOfModel(getArrayArrayOfModel());
+  }
+
 }
 

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

@@ -147,5 +147,59 @@ public class Banana {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private Banana instance;
+
+    public Builder() {
+      this(new Banana());
+    }
+
+    protected Builder(Banana instance) {
+      this.instance = instance;
+    }
+
+    public Banana.Builder lengthCm(BigDecimal lengthCm) {
+      this.instance.lengthCm = lengthCm;
+      return this;
+    }
+
+
+    /**
+    * returns a built Banana instance.
+    *
+    * The builder is not reusable.
+    */
+    public Banana build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static Banana.Builder builder() {
+    return new Banana.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public Banana.Builder toBuilder() {
+    return new Banana.Builder()
+      .lengthCm(getLengthCm());
+  }
+
 }
 

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

@@ -183,5 +183,64 @@ public class BananaReq {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private BananaReq instance;
+
+    public Builder() {
+      this(new BananaReq());
+    }
+
+    protected Builder(BananaReq instance) {
+      this.instance = instance;
+    }
+
+    public BananaReq.Builder lengthCm(BigDecimal lengthCm) {
+      this.instance.lengthCm = lengthCm;
+      return this;
+    }
+    public BananaReq.Builder sweet(Boolean sweet) {
+      this.instance.sweet = sweet;
+      return this;
+    }
+
+
+    /**
+    * returns a built BananaReq instance.
+    *
+    * The builder is not reusable.
+    */
+    public BananaReq build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static BananaReq.Builder builder() {
+    return new BananaReq.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public BananaReq.Builder toBuilder() {
+    return new BananaReq.Builder()
+      .lengthCm(getLengthCm())
+      .sweet(getSweet());
+  }
+
 }
 

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

@@ -146,5 +146,59 @@ public class BasquePig {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private BasquePig instance;
+
+    public Builder() {
+      this(new BasquePig());
+    }
+
+    protected Builder(BasquePig instance) {
+      this.instance = instance;
+    }
+
+    public BasquePig.Builder className(String className) {
+      this.instance.className = className;
+      return this;
+    }
+
+
+    /**
+    * returns a built BasquePig instance.
+    *
+    * The builder is not reusable.
+    */
+    public BasquePig build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static BasquePig.Builder builder() {
+    return new BasquePig.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public BasquePig.Builder toBuilder() {
+    return new BasquePig.Builder()
+      .className(getClassName());
+  }
+
 }
 

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

@@ -326,5 +326,84 @@ public class Capitalization {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private Capitalization instance;
+
+    public Builder() {
+      this(new Capitalization());
+    }
+
+    protected Builder(Capitalization instance) {
+      this.instance = instance;
+    }
+
+    public Capitalization.Builder smallCamel(String smallCamel) {
+      this.instance.smallCamel = smallCamel;
+      return this;
+    }
+    public Capitalization.Builder capitalCamel(String capitalCamel) {
+      this.instance.capitalCamel = capitalCamel;
+      return this;
+    }
+    public Capitalization.Builder smallSnake(String smallSnake) {
+      this.instance.smallSnake = smallSnake;
+      return this;
+    }
+    public Capitalization.Builder capitalSnake(String capitalSnake) {
+      this.instance.capitalSnake = capitalSnake;
+      return this;
+    }
+    public Capitalization.Builder scAETHFlowPoints(String scAETHFlowPoints) {
+      this.instance.scAETHFlowPoints = scAETHFlowPoints;
+      return this;
+    }
+    public Capitalization.Builder ATT_NAME(String ATT_NAME) {
+      this.instance.ATT_NAME = ATT_NAME;
+      return this;
+    }
+
+
+    /**
+    * returns a built Capitalization instance.
+    *
+    * The builder is not reusable.
+    */
+    public Capitalization build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static Capitalization.Builder builder() {
+    return new Capitalization.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public Capitalization.Builder toBuilder() {
+    return new Capitalization.Builder()
+      .smallCamel(getSmallCamel())
+      .capitalCamel(getCapitalCamel())
+      .smallSnake(getSmallSnake())
+      .capitalSnake(getCapitalSnake())
+      .scAETHFlowPoints(getScAETHFlowPoints())
+      .ATT_NAME(getATTNAME());
+  }
+
 }
 

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

@@ -188,5 +188,73 @@ static {
   mappings.put("Cat", Cat.class);
   JSON.registerDiscriminator(Cat.class, "className", mappings);
 }
+
+    public static class Builder extends Animal.Builder {
+
+    private Cat instance;
+
+    public Builder() {
+      this(new Cat());
+    }
+
+    protected Builder(Cat instance) {
+      super(instance);
+      this.instance = instance;
+    }
+
+    public Cat.Builder declawed(Boolean declawed) {
+      this.instance.declawed = declawed;
+      return this;
+    }
+
+    public Cat.Builder className(String className) { // inherited: true
+      super.className(className);
+      return this;
+   }
+
+    public Cat.Builder color(String color) { // inherited: true
+      super.color(color);
+      return this;
+   }
+
+
+    /**
+    * returns a built Cat instance.
+    *
+    * The builder is not reusable.
+    */
+    public Cat build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        super.build();
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static Cat.Builder builder() {
+    return new Cat.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public Cat.Builder toBuilder() {
+    return new Cat.Builder()
+      .className(getClassName())
+      .color(getColor())
+      .declawed(getDeclawed());
+  }
+
 }
 

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

@@ -182,5 +182,64 @@ public class Category {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private Category instance;
+
+    public Builder() {
+      this(new Category());
+    }
+
+    protected Builder(Category instance) {
+      this.instance = instance;
+    }
+
+    public Category.Builder id(Long id) {
+      this.instance.id = id;
+      return this;
+    }
+    public Category.Builder name(String name) {
+      this.instance.name = name;
+      return this;
+    }
+
+
+    /**
+    * returns a built Category instance.
+    *
+    * The builder is not reusable.
+    */
+    public Category build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static Category.Builder builder() {
+    return new Category.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public Category.Builder toBuilder() {
+    return new Category.Builder()
+      .id(getId())
+      .name(getName());
+  }
+
 }
 

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

@@ -215,5 +215,66 @@ static {
   mappings.put("ChildCat", ChildCat.class);
   JSON.registerDiscriminator(ChildCat.class, "pet_type", mappings);
 }
+
+    public static class Builder extends ParentPet.Builder {
+
+    private ChildCat instance;
+
+    public Builder() {
+      this(new ChildCat());
+    }
+
+    protected Builder(ChildCat instance) {
+      super(instance);
+      this.instance = instance;
+    }
+
+    public ChildCat.Builder name(String name) {
+      this.instance.name = name;
+      return this;
+    }
+    public ChildCat.Builder petType(String petType) {
+      this.instance.petType = petType;
+      return this;
+    }
+
+
+    /**
+    * returns a built ChildCat instance.
+    *
+    * The builder is not reusable.
+    */
+    public ChildCat build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        super.build();
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static ChildCat.Builder builder() {
+    return new ChildCat.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public ChildCat.Builder toBuilder() {
+    return new ChildCat.Builder()
+      .petType(getPetType())
+      .name(getName());
+  }
+
 }
 

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

@@ -146,5 +146,59 @@ public class ClassModel {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private ClassModel instance;
+
+    public Builder() {
+      this(new ClassModel());
+    }
+
+    protected Builder(ClassModel instance) {
+      this.instance = instance;
+    }
+
+    public ClassModel.Builder propertyClass(String propertyClass) {
+      this.instance.propertyClass = propertyClass;
+      return this;
+    }
+
+
+    /**
+    * returns a built ClassModel instance.
+    *
+    * The builder is not reusable.
+    */
+    public ClassModel build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static ClassModel.Builder builder() {
+    return new ClassModel.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public ClassModel.Builder toBuilder() {
+    return new ClassModel.Builder()
+      .propertyClass(getPropertyClass());
+  }
+
 }
 

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

@@ -146,5 +146,59 @@ public class Client {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private Client instance;
+
+    public Builder() {
+      this(new Client());
+    }
+
+    protected Builder(Client instance) {
+      this.instance = instance;
+    }
+
+    public Client.Builder client(String client) {
+      this.instance.client = client;
+      return this;
+    }
+
+
+    /**
+    * returns a built Client instance.
+    *
+    * The builder is not reusable.
+    */
+    public Client build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static Client.Builder builder() {
+    return new Client.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public Client.Builder toBuilder() {
+    return new Client.Builder()
+      .client(getClient());
+  }
+
 }
 

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

@@ -182,5 +182,64 @@ public class ComplexQuadrilateral {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private ComplexQuadrilateral instance;
+
+    public Builder() {
+      this(new ComplexQuadrilateral());
+    }
+
+    protected Builder(ComplexQuadrilateral instance) {
+      this.instance = instance;
+    }
+
+    public ComplexQuadrilateral.Builder shapeType(String shapeType) {
+      this.instance.shapeType = shapeType;
+      return this;
+    }
+    public ComplexQuadrilateral.Builder quadrilateralType(String quadrilateralType) {
+      this.instance.quadrilateralType = quadrilateralType;
+      return this;
+    }
+
+
+    /**
+    * returns a built ComplexQuadrilateral instance.
+    *
+    * The builder is not reusable.
+    */
+    public ComplexQuadrilateral build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static ComplexQuadrilateral.Builder builder() {
+    return new ComplexQuadrilateral.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public ComplexQuadrilateral.Builder toBuilder() {
+    return new ComplexQuadrilateral.Builder()
+      .shapeType(getShapeType())
+      .quadrilateralType(getQuadrilateralType());
+  }
+
 }
 

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

@@ -146,5 +146,59 @@ public class DanishPig {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private DanishPig instance;
+
+    public Builder() {
+      this(new DanishPig());
+    }
+
+    protected Builder(DanishPig instance) {
+      this.instance = instance;
+    }
+
+    public DanishPig.Builder className(String className) {
+      this.instance.className = className;
+      return this;
+    }
+
+
+    /**
+    * returns a built DanishPig instance.
+    *
+    * The builder is not reusable.
+    */
+    public DanishPig build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static DanishPig.Builder builder() {
+    return new DanishPig.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public DanishPig.Builder toBuilder() {
+    return new DanishPig.Builder()
+      .className(getClassName());
+  }
+
 }
 

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

@@ -148,5 +148,59 @@ public class DeprecatedObject {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private DeprecatedObject instance;
+
+    public Builder() {
+      this(new DeprecatedObject());
+    }
+
+    protected Builder(DeprecatedObject instance) {
+      this.instance = instance;
+    }
+
+    public DeprecatedObject.Builder name(String name) {
+      this.instance.name = name;
+      return this;
+    }
+
+
+    /**
+    * returns a built DeprecatedObject instance.
+    *
+    * The builder is not reusable.
+    */
+    public DeprecatedObject build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static DeprecatedObject.Builder builder() {
+    return new DeprecatedObject.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public DeprecatedObject.Builder toBuilder() {
+    return new DeprecatedObject.Builder()
+      .name(getName());
+  }
+
 }
 

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

@@ -187,5 +187,73 @@ static {
   mappings.put("Dog", Dog.class);
   JSON.registerDiscriminator(Dog.class, "className", mappings);
 }
+
+    public static class Builder extends Animal.Builder {
+
+    private Dog instance;
+
+    public Builder() {
+      this(new Dog());
+    }
+
+    protected Builder(Dog instance) {
+      super(instance);
+      this.instance = instance;
+    }
+
+    public Dog.Builder breed(String breed) {
+      this.instance.breed = breed;
+      return this;
+    }
+
+    public Dog.Builder className(String className) { // inherited: true
+      super.className(className);
+      return this;
+   }
+
+    public Dog.Builder color(String color) { // inherited: true
+      super.color(color);
+      return this;
+   }
+
+
+    /**
+    * returns a built Dog instance.
+    *
+    * The builder is not reusable.
+    */
+    public Dog build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        super.build();
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static Dog.Builder builder() {
+    return new Dog.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public Dog.Builder toBuilder() {
+    return new Dog.Builder()
+      .className(getClassName())
+      .color(getColor())
+      .breed(getBreed());
+  }
+
 }
 

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

@@ -349,5 +349,78 @@ public class Drawing extends HashMap<String, Fruit> {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private Drawing instance;
+
+    public Builder() {
+      this(new Drawing());
+    }
+
+    protected Builder(Drawing instance) {
+      this.instance = instance;
+    }
+
+    public Drawing.Builder mainShape(Shape mainShape) {
+      this.instance.mainShape = mainShape;
+      return this;
+    }
+    public Drawing.Builder shapeOrNull(ShapeOrNull shapeOrNull) {
+      this.instance.shapeOrNull = shapeOrNull;
+      return this;
+    }
+    public Drawing.Builder nullableShape(NullableShape nullableShape) {
+      this.instance.nullableShape = JsonNullable.<NullableShape>of(nullableShape);
+      return this;
+    }
+    public Drawing.Builder nullableShape(JsonNullable<NullableShape> nullableShape) {
+      this.instance.nullableShape = nullableShape;
+      return this;
+    }
+    public Drawing.Builder shapes(List<Shape> shapes) {
+      this.instance.shapes = shapes;
+      return this;
+    }
+
+
+    /**
+    * returns a built Drawing instance.
+    *
+    * The builder is not reusable.
+    */
+    public Drawing build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static Drawing.Builder builder() {
+    return new Drawing.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public Drawing.Builder toBuilder() {
+    return new Drawing.Builder()
+      .mainShape(getMainShape())
+      .shapeOrNull(getShapeOrNull())
+      .nullableShape(getNullableShape())
+      .shapes(getShapes());
+  }
+
 }
 

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

@@ -266,5 +266,64 @@ public class EnumArrays {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private EnumArrays instance;
+
+    public Builder() {
+      this(new EnumArrays());
+    }
+
+    protected Builder(EnumArrays instance) {
+      this.instance = instance;
+    }
+
+    public EnumArrays.Builder justSymbol(JustSymbolEnum justSymbol) {
+      this.instance.justSymbol = justSymbol;
+      return this;
+    }
+    public EnumArrays.Builder arrayEnum(List<ArrayEnumEnum> arrayEnum) {
+      this.instance.arrayEnum = arrayEnum;
+      return this;
+    }
+
+
+    /**
+    * returns a built EnumArrays instance.
+    *
+    * The builder is not reusable.
+    */
+    public EnumArrays build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static EnumArrays.Builder builder() {
+    return new EnumArrays.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public EnumArrays.Builder toBuilder() {
+    return new EnumArrays.Builder()
+      .justSymbol(getJustSymbol())
+      .arrayEnum(getArrayEnum());
+  }
+
 }
 

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

@@ -640,5 +640,103 @@ public class EnumTest {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private EnumTest instance;
+
+    public Builder() {
+      this(new EnumTest());
+    }
+
+    protected Builder(EnumTest instance) {
+      this.instance = instance;
+    }
+
+    public EnumTest.Builder enumString(EnumStringEnum enumString) {
+      this.instance.enumString = enumString;
+      return this;
+    }
+    public EnumTest.Builder enumStringRequired(EnumStringRequiredEnum enumStringRequired) {
+      this.instance.enumStringRequired = enumStringRequired;
+      return this;
+    }
+    public EnumTest.Builder enumInteger(EnumIntegerEnum enumInteger) {
+      this.instance.enumInteger = enumInteger;
+      return this;
+    }
+    public EnumTest.Builder enumIntegerOnly(EnumIntegerOnlyEnum enumIntegerOnly) {
+      this.instance.enumIntegerOnly = enumIntegerOnly;
+      return this;
+    }
+    public EnumTest.Builder enumNumber(EnumNumberEnum enumNumber) {
+      this.instance.enumNumber = enumNumber;
+      return this;
+    }
+    public EnumTest.Builder outerEnum(OuterEnum outerEnum) {
+      this.instance.outerEnum = JsonNullable.<OuterEnum>of(outerEnum);
+      return this;
+    }
+    public EnumTest.Builder outerEnum(JsonNullable<OuterEnum> outerEnum) {
+      this.instance.outerEnum = outerEnum;
+      return this;
+    }
+    public EnumTest.Builder outerEnumInteger(OuterEnumInteger outerEnumInteger) {
+      this.instance.outerEnumInteger = outerEnumInteger;
+      return this;
+    }
+    public EnumTest.Builder outerEnumDefaultValue(OuterEnumDefaultValue outerEnumDefaultValue) {
+      this.instance.outerEnumDefaultValue = outerEnumDefaultValue;
+      return this;
+    }
+    public EnumTest.Builder outerEnumIntegerDefaultValue(OuterEnumIntegerDefaultValue outerEnumIntegerDefaultValue) {
+      this.instance.outerEnumIntegerDefaultValue = outerEnumIntegerDefaultValue;
+      return this;
+    }
+
+
+    /**
+    * returns a built EnumTest instance.
+    *
+    * The builder is not reusable.
+    */
+    public EnumTest build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static EnumTest.Builder builder() {
+    return new EnumTest.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public EnumTest.Builder toBuilder() {
+    return new EnumTest.Builder()
+      .enumString(getEnumString())
+      .enumStringRequired(getEnumStringRequired())
+      .enumInteger(getEnumInteger())
+      .enumIntegerOnly(getEnumIntegerOnly())
+      .enumNumber(getEnumNumber())
+      .outerEnum(getOuterEnum())
+      .outerEnumInteger(getOuterEnumInteger())
+      .outerEnumDefaultValue(getOuterEnumDefaultValue())
+      .outerEnumIntegerDefaultValue(getOuterEnumIntegerDefaultValue());
+  }
+
 }
 

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

@@ -182,5 +182,64 @@ public class EquilateralTriangle {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private EquilateralTriangle instance;
+
+    public Builder() {
+      this(new EquilateralTriangle());
+    }
+
+    protected Builder(EquilateralTriangle instance) {
+      this.instance = instance;
+    }
+
+    public EquilateralTriangle.Builder shapeType(String shapeType) {
+      this.instance.shapeType = shapeType;
+      return this;
+    }
+    public EquilateralTriangle.Builder triangleType(String triangleType) {
+      this.instance.triangleType = triangleType;
+      return this;
+    }
+
+
+    /**
+    * returns a built EquilateralTriangle instance.
+    *
+    * The builder is not reusable.
+    */
+    public EquilateralTriangle build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static EquilateralTriangle.Builder builder() {
+    return new EquilateralTriangle.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public EquilateralTriangle.Builder toBuilder() {
+    return new EquilateralTriangle.Builder()
+      .shapeType(getShapeType())
+      .triangleType(getTriangleType());
+  }
+
 }
 

samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/FakeBigDecimalMap200Response.java

@@ -197,5 +197,64 @@ public class FakeBigDecimalMap200Response {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private FakeBigDecimalMap200Response instance;
+
+    public Builder() {
+      this(new FakeBigDecimalMap200Response());
+    }
+
+    protected Builder(FakeBigDecimalMap200Response instance) {
+      this.instance = instance;
+    }
+
+    public FakeBigDecimalMap200Response.Builder someId(BigDecimal someId) {
+      this.instance.someId = someId;
+      return this;
+    }
+    public FakeBigDecimalMap200Response.Builder someMap(Map<String, BigDecimal> someMap) {
+      this.instance.someMap = someMap;
+      return this;
+    }
+
+
+    /**
+    * returns a built FakeBigDecimalMap200Response instance.
+    *
+    * The builder is not reusable.
+    */
+    public FakeBigDecimalMap200Response build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static FakeBigDecimalMap200Response.Builder builder() {
+    return new FakeBigDecimalMap200Response.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public FakeBigDecimalMap200Response.Builder toBuilder() {
+    return new FakeBigDecimalMap200Response.Builder()
+      .someId(getSomeId())
+      .someMap(getSomeMap());
+  }
+
 }
 

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

@@ -198,5 +198,64 @@ public class FileSchemaTestClass {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private FileSchemaTestClass instance;
+
+    public Builder() {
+      this(new FileSchemaTestClass());
+    }
+
+    protected Builder(FileSchemaTestClass instance) {
+      this.instance = instance;
+    }
+
+    public FileSchemaTestClass.Builder _file(ModelFile _file) {
+      this.instance._file = _file;
+      return this;
+    }
+    public FileSchemaTestClass.Builder files(List<ModelFile> files) {
+      this.instance.files = files;
+      return this;
+    }
+
+
+    /**
+    * returns a built FileSchemaTestClass instance.
+    *
+    * The builder is not reusable.
+    */
+    public FileSchemaTestClass build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static FileSchemaTestClass.Builder builder() {
+    return new FileSchemaTestClass.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public FileSchemaTestClass.Builder toBuilder() {
+    return new FileSchemaTestClass.Builder()
+      ._file(getFile())
+      .files(getFiles());
+  }
+
 }
 

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

@@ -146,5 +146,59 @@ public class Foo {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private Foo instance;
+
+    public Builder() {
+      this(new Foo());
+    }
+
+    protected Builder(Foo instance) {
+      this.instance = instance;
+    }
+
+    public Foo.Builder bar(String bar) {
+      this.instance.bar = bar;
+      return this;
+    }
+
+
+    /**
+    * returns a built Foo instance.
+    *
+    * The builder is not reusable.
+    */
+    public Foo build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static Foo.Builder builder() {
+    return new Foo.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public Foo.Builder toBuilder() {
+    return new Foo.Builder()
+      .bar(getBar());
+  }
+
 }
 

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

@@ -147,5 +147,59 @@ public class FooGetDefaultResponse {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private FooGetDefaultResponse instance;
+
+    public Builder() {
+      this(new FooGetDefaultResponse());
+    }
+
+    protected Builder(FooGetDefaultResponse instance) {
+      this.instance = instance;
+    }
+
+    public FooGetDefaultResponse.Builder string(Foo string) {
+      this.instance.string = string;
+      return this;
+    }
+
+
+    /**
+    * returns a built FooGetDefaultResponse instance.
+    *
+    * The builder is not reusable.
+    */
+    public FooGetDefaultResponse build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static FooGetDefaultResponse.Builder builder() {
+    return new FooGetDefaultResponse.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public FooGetDefaultResponse.Builder toBuilder() {
+    return new FooGetDefaultResponse.Builder()
+      .string(getString());
+  }
+
 }
 

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

@@ -701,5 +701,134 @@ public class FormatTest {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private FormatTest instance;
+
+    public Builder() {
+      this(new FormatTest());
+    }
+
+    protected Builder(FormatTest instance) {
+      this.instance = instance;
+    }
+
+    public FormatTest.Builder integer(Integer integer) {
+      this.instance.integer = integer;
+      return this;
+    }
+    public FormatTest.Builder int32(Integer int32) {
+      this.instance.int32 = int32;
+      return this;
+    }
+    public FormatTest.Builder int64(Long int64) {
+      this.instance.int64 = int64;
+      return this;
+    }
+    public FormatTest.Builder number(BigDecimal number) {
+      this.instance.number = number;
+      return this;
+    }
+    public FormatTest.Builder _float(Float _float) {
+      this.instance._float = _float;
+      return this;
+    }
+    public FormatTest.Builder _double(Double _double) {
+      this.instance._double = _double;
+      return this;
+    }
+    public FormatTest.Builder decimal(BigDecimal decimal) {
+      this.instance.decimal = decimal;
+      return this;
+    }
+    public FormatTest.Builder string(String string) {
+      this.instance.string = string;
+      return this;
+    }
+    public FormatTest.Builder _byte(byte[] _byte) {
+      this.instance._byte = _byte;
+      return this;
+    }
+    public FormatTest.Builder binary(File binary) {
+      this.instance.binary = binary;
+      return this;
+    }
+    public FormatTest.Builder date(LocalDate date) {
+      this.instance.date = date;
+      return this;
+    }
+    public FormatTest.Builder dateTime(OffsetDateTime dateTime) {
+      this.instance.dateTime = dateTime;
+      return this;
+    }
+    public FormatTest.Builder uuid(UUID uuid) {
+      this.instance.uuid = uuid;
+      return this;
+    }
+    public FormatTest.Builder password(String password) {
+      this.instance.password = password;
+      return this;
+    }
+    public FormatTest.Builder patternWithDigits(String patternWithDigits) {
+      this.instance.patternWithDigits = patternWithDigits;
+      return this;
+    }
+    public FormatTest.Builder patternWithDigitsAndDelimiter(String patternWithDigitsAndDelimiter) {
+      this.instance.patternWithDigitsAndDelimiter = patternWithDigitsAndDelimiter;
+      return this;
+    }
+
+
+    /**
+    * returns a built FormatTest instance.
+    *
+    * The builder is not reusable.
+    */
+    public FormatTest build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static FormatTest.Builder builder() {
+    return new FormatTest.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public FormatTest.Builder toBuilder() {
+    return new FormatTest.Builder()
+      .integer(getInteger())
+      .int32(getInt32())
+      .int64(getInt64())
+      .number(getNumber())
+      ._float(getFloat())
+      ._double(getDouble())
+      .decimal(getDecimal())
+      .string(getString())
+      ._byte(getByte())
+      .binary(getBinary())
+      .date(getDate())
+      .dateTime(getDateTime())
+      .uuid(getUuid())
+      .password(getPassword())
+      .patternWithDigits(getPatternWithDigits())
+      .patternWithDigitsAndDelimiter(getPatternWithDigitsAndDelimiter());
+  }
+
 }
 

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

@@ -168,5 +168,59 @@ static {
   mappings.put("GrandparentAnimal", GrandparentAnimal.class);
   JSON.registerDiscriminator(GrandparentAnimal.class, "pet_type", mappings);
 }
+
+    public static class Builder {
+
+    private GrandparentAnimal instance;
+
+    public Builder() {
+      this(new GrandparentAnimal());
+    }
+
+    protected Builder(GrandparentAnimal instance) {
+      this.instance = instance;
+    }
+
+    public GrandparentAnimal.Builder petType(String petType) {
+      this.instance.petType = petType;
+      return this;
+    }
+
+
+    /**
+    * returns a built GrandparentAnimal instance.
+    *
+    * The builder is not reusable.
+    */
+    public GrandparentAnimal build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static GrandparentAnimal.Builder builder() {
+    return new GrandparentAnimal.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public GrandparentAnimal.Builder toBuilder() {
+    return new GrandparentAnimal.Builder()
+      .petType(getPetType());
+  }
+
 }
 

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

@@ -172,5 +172,64 @@ public class HasOnlyReadOnly {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private HasOnlyReadOnly instance;
+
+    public Builder() {
+      this(new HasOnlyReadOnly());
+    }
+
+    protected Builder(HasOnlyReadOnly instance) {
+      this.instance = instance;
+    }
+
+    public HasOnlyReadOnly.Builder bar(String bar) {
+      this.instance.bar = bar;
+      return this;
+    }
+    public HasOnlyReadOnly.Builder foo(String foo) {
+      this.instance.foo = foo;
+      return this;
+    }
+
+
+    /**
+    * returns a built HasOnlyReadOnly instance.
+    *
+    * The builder is not reusable.
+    */
+    public HasOnlyReadOnly build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static HasOnlyReadOnly.Builder builder() {
+    return new HasOnlyReadOnly.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public HasOnlyReadOnly.Builder toBuilder() {
+    return new HasOnlyReadOnly.Builder()
+      .bar(getBar())
+      .foo(getFoo());
+  }
+
 }
 

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

@@ -169,5 +169,63 @@ public class HealthCheckResult {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private HealthCheckResult instance;
+
+    public Builder() {
+      this(new HealthCheckResult());
+    }
+
+    protected Builder(HealthCheckResult instance) {
+      this.instance = instance;
+    }
+
+    public HealthCheckResult.Builder nullableMessage(String nullableMessage) {
+      this.instance.nullableMessage = JsonNullable.<String>of(nullableMessage);
+      return this;
+    }
+    public HealthCheckResult.Builder nullableMessage(JsonNullable<String> nullableMessage) {
+      this.instance.nullableMessage = nullableMessage;
+      return this;
+    }
+
+
+    /**
+    * returns a built HealthCheckResult instance.
+    *
+    * The builder is not reusable.
+    */
+    public HealthCheckResult build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static HealthCheckResult.Builder builder() {
+    return new HealthCheckResult.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public HealthCheckResult.Builder toBuilder() {
+    return new HealthCheckResult.Builder()
+      .nullableMessage(getNullableMessage());
+  }
+
 }
 

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

@@ -182,5 +182,64 @@ public class IsoscelesTriangle {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private IsoscelesTriangle instance;
+
+    public Builder() {
+      this(new IsoscelesTriangle());
+    }
+
+    protected Builder(IsoscelesTriangle instance) {
+      this.instance = instance;
+    }
+
+    public IsoscelesTriangle.Builder shapeType(String shapeType) {
+      this.instance.shapeType = shapeType;
+      return this;
+    }
+    public IsoscelesTriangle.Builder triangleType(String triangleType) {
+      this.instance.triangleType = triangleType;
+      return this;
+    }
+
+
+    /**
+    * returns a built IsoscelesTriangle instance.
+    *
+    * The builder is not reusable.
+    */
+    public IsoscelesTriangle build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static IsoscelesTriangle.Builder builder() {
+    return new IsoscelesTriangle.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public IsoscelesTriangle.Builder toBuilder() {
+    return new IsoscelesTriangle.Builder()
+      .shapeType(getShapeType())
+      .triangleType(getTriangleType());
+  }
+
 }
 

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

@@ -339,5 +339,74 @@ public class MapTest {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private MapTest instance;
+
+    public Builder() {
+      this(new MapTest());
+    }
+
+    protected Builder(MapTest instance) {
+      this.instance = instance;
+    }
+
+    public MapTest.Builder mapMapOfString(Map<String, Map<String, String>> mapMapOfString) {
+      this.instance.mapMapOfString = mapMapOfString;
+      return this;
+    }
+    public MapTest.Builder mapOfEnumString(Map<String, InnerEnum> mapOfEnumString) {
+      this.instance.mapOfEnumString = mapOfEnumString;
+      return this;
+    }
+    public MapTest.Builder directMap(Map<String, Boolean> directMap) {
+      this.instance.directMap = directMap;
+      return this;
+    }
+    public MapTest.Builder indirectMap(Map<String, Boolean> indirectMap) {
+      this.instance.indirectMap = indirectMap;
+      return this;
+    }
+
+
+    /**
+    * returns a built MapTest instance.
+    *
+    * The builder is not reusable.
+    */
+    public MapTest build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static MapTest.Builder builder() {
+    return new MapTest.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public MapTest.Builder toBuilder() {
+    return new MapTest.Builder()
+      .mapMapOfString(getMapMapOfString())
+      .mapOfEnumString(getMapOfEnumString())
+      .directMap(getDirectMap())
+      .indirectMap(getIndirectMap());
+  }
+
 }
 

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

@@ -236,5 +236,69 @@ public class MixedPropertiesAndAdditionalPropertiesClass {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private MixedPropertiesAndAdditionalPropertiesClass instance;
+
+    public Builder() {
+      this(new MixedPropertiesAndAdditionalPropertiesClass());
+    }
+
+    protected Builder(MixedPropertiesAndAdditionalPropertiesClass instance) {
+      this.instance = instance;
+    }
+
+    public MixedPropertiesAndAdditionalPropertiesClass.Builder uuid(UUID uuid) {
+      this.instance.uuid = uuid;
+      return this;
+    }
+    public MixedPropertiesAndAdditionalPropertiesClass.Builder dateTime(OffsetDateTime dateTime) {
+      this.instance.dateTime = dateTime;
+      return this;
+    }
+    public MixedPropertiesAndAdditionalPropertiesClass.Builder map(Map<String, Animal> map) {
+      this.instance.map = map;
+      return this;
+    }
+
+
+    /**
+    * returns a built MixedPropertiesAndAdditionalPropertiesClass instance.
+    *
+    * The builder is not reusable.
+    */
+    public MixedPropertiesAndAdditionalPropertiesClass build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static MixedPropertiesAndAdditionalPropertiesClass.Builder builder() {
+    return new MixedPropertiesAndAdditionalPropertiesClass.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public MixedPropertiesAndAdditionalPropertiesClass.Builder toBuilder() {
+    return new MixedPropertiesAndAdditionalPropertiesClass.Builder()
+      .uuid(getUuid())
+      .dateTime(getDateTime())
+      .map(getMap());
+  }
+
 }
 

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

@@ -182,5 +182,64 @@ public class Model200Response {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private Model200Response instance;
+
+    public Builder() {
+      this(new Model200Response());
+    }
+
+    protected Builder(Model200Response instance) {
+      this.instance = instance;
+    }
+
+    public Model200Response.Builder name(Integer name) {
+      this.instance.name = name;
+      return this;
+    }
+    public Model200Response.Builder propertyClass(String propertyClass) {
+      this.instance.propertyClass = propertyClass;
+      return this;
+    }
+
+
+    /**
+    * returns a built Model200Response instance.
+    *
+    * The builder is not reusable.
+    */
+    public Model200Response build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static Model200Response.Builder builder() {
+    return new Model200Response.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public Model200Response.Builder toBuilder() {
+    return new Model200Response.Builder()
+      .name(getName())
+      .propertyClass(getPropertyClass());
+  }
+
 }
 

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

@@ -218,5 +218,69 @@ public class ModelApiResponse {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private ModelApiResponse instance;
+
+    public Builder() {
+      this(new ModelApiResponse());
+    }
+
+    protected Builder(ModelApiResponse instance) {
+      this.instance = instance;
+    }
+
+    public ModelApiResponse.Builder code(Integer code) {
+      this.instance.code = code;
+      return this;
+    }
+    public ModelApiResponse.Builder type(String type) {
+      this.instance.type = type;
+      return this;
+    }
+    public ModelApiResponse.Builder message(String message) {
+      this.instance.message = message;
+      return this;
+    }
+
+
+    /**
+    * returns a built ModelApiResponse instance.
+    *
+    * The builder is not reusable.
+    */
+    public ModelApiResponse build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static ModelApiResponse.Builder builder() {
+    return new ModelApiResponse.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public ModelApiResponse.Builder toBuilder() {
+    return new ModelApiResponse.Builder()
+      .code(getCode())
+      .type(getType())
+      .message(getMessage());
+  }
+
 }
 

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

@@ -146,5 +146,59 @@ public class ModelFile {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private ModelFile instance;
+
+    public Builder() {
+      this(new ModelFile());
+    }
+
+    protected Builder(ModelFile instance) {
+      this.instance = instance;
+    }
+
+    public ModelFile.Builder sourceURI(String sourceURI) {
+      this.instance.sourceURI = sourceURI;
+      return this;
+    }
+
+
+    /**
+    * returns a built ModelFile instance.
+    *
+    * The builder is not reusable.
+    */
+    public ModelFile build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static ModelFile.Builder builder() {
+    return new ModelFile.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public ModelFile.Builder toBuilder() {
+    return new ModelFile.Builder()
+      .sourceURI(getSourceURI());
+  }
+
 }
 

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

@@ -146,5 +146,59 @@ public class ModelList {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private ModelList instance;
+
+    public Builder() {
+      this(new ModelList());
+    }
+
+    protected Builder(ModelList instance) {
+      this.instance = instance;
+    }
+
+    public ModelList.Builder _123list(String _123list) {
+      this.instance._123list = _123list;
+      return this;
+    }
+
+
+    /**
+    * returns a built ModelList instance.
+    *
+    * The builder is not reusable.
+    */
+    public ModelList build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static ModelList.Builder builder() {
+    return new ModelList.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public ModelList.Builder toBuilder() {
+    return new ModelList.Builder()
+      ._123list(get123list());
+  }
+
 }
 

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

@@ -146,5 +146,59 @@ public class ModelReturn {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private ModelReturn instance;
+
+    public Builder() {
+      this(new ModelReturn());
+    }
+
+    protected Builder(ModelReturn instance) {
+      this.instance = instance;
+    }
+
+    public ModelReturn.Builder _return(Integer _return) {
+      this.instance._return = _return;
+      return this;
+    }
+
+
+    /**
+    * returns a built ModelReturn instance.
+    *
+    * The builder is not reusable.
+    */
+    public ModelReturn build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static ModelReturn.Builder builder() {
+    return new ModelReturn.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public ModelReturn.Builder toBuilder() {
+    return new ModelReturn.Builder()
+      ._return(getReturn());
+  }
+
 }
 

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

@@ -244,5 +244,74 @@ public class Name {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private Name instance;
+
+    public Builder() {
+      this(new Name());
+    }
+
+    protected Builder(Name instance) {
+      this.instance = instance;
+    }
+
+    public Name.Builder name(Integer name) {
+      this.instance.name = name;
+      return this;
+    }
+    public Name.Builder snakeCase(Integer snakeCase) {
+      this.instance.snakeCase = snakeCase;
+      return this;
+    }
+    public Name.Builder property(String property) {
+      this.instance.property = property;
+      return this;
+    }
+    public Name.Builder _123number(Integer _123number) {
+      this.instance._123number = _123number;
+      return this;
+    }
+
+
+    /**
+    * returns a built Name instance.
+    *
+    * The builder is not reusable.
+    */
+    public Name build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static Name.Builder builder() {
+    return new Name.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public Name.Builder toBuilder() {
+    return new Name.Builder()
+      .name(getName())
+      .snakeCase(getSnakeCase())
+      .property(getProperty())
+      ._123number(get123number());
+  }
+
 }
 

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

@@ -783,5 +783,154 @@ public class NullableClass extends HashMap<String, Object> {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private NullableClass instance;
+
+    public Builder() {
+      this(new NullableClass());
+    }
+
+    protected Builder(NullableClass instance) {
+      this.instance = instance;
+    }
+
+    public NullableClass.Builder integerProp(Integer integerProp) {
+      this.instance.integerProp = JsonNullable.<Integer>of(integerProp);
+      return this;
+    }
+    public NullableClass.Builder integerProp(JsonNullable<Integer> integerProp) {
+      this.instance.integerProp = integerProp;
+      return this;
+    }
+    public NullableClass.Builder numberProp(BigDecimal numberProp) {
+      this.instance.numberProp = JsonNullable.<BigDecimal>of(numberProp);
+      return this;
+    }
+    public NullableClass.Builder numberProp(JsonNullable<BigDecimal> numberProp) {
+      this.instance.numberProp = numberProp;
+      return this;
+    }
+    public NullableClass.Builder booleanProp(Boolean booleanProp) {
+      this.instance.booleanProp = JsonNullable.<Boolean>of(booleanProp);
+      return this;
+    }
+    public NullableClass.Builder booleanProp(JsonNullable<Boolean> booleanProp) {
+      this.instance.booleanProp = booleanProp;
+      return this;
+    }
+    public NullableClass.Builder stringProp(String stringProp) {
+      this.instance.stringProp = JsonNullable.<String>of(stringProp);
+      return this;
+    }
+    public NullableClass.Builder stringProp(JsonNullable<String> stringProp) {
+      this.instance.stringProp = stringProp;
+      return this;
+    }
+    public NullableClass.Builder dateProp(LocalDate dateProp) {
+      this.instance.dateProp = JsonNullable.<LocalDate>of(dateProp);
+      return this;
+    }
+    public NullableClass.Builder dateProp(JsonNullable<LocalDate> dateProp) {
+      this.instance.dateProp = dateProp;
+      return this;
+    }
+    public NullableClass.Builder datetimeProp(OffsetDateTime datetimeProp) {
+      this.instance.datetimeProp = JsonNullable.<OffsetDateTime>of(datetimeProp);
+      return this;
+    }
+    public NullableClass.Builder datetimeProp(JsonNullable<OffsetDateTime> datetimeProp) {
+      this.instance.datetimeProp = datetimeProp;
+      return this;
+    }
+    public NullableClass.Builder arrayNullableProp(List<Object> arrayNullableProp) {
+      this.instance.arrayNullableProp = JsonNullable.<List<Object>>of(arrayNullableProp);
+      return this;
+    }
+    public NullableClass.Builder arrayNullableProp(JsonNullable<List<Object>> arrayNullableProp) {
+      this.instance.arrayNullableProp = arrayNullableProp;
+      return this;
+    }
+    public NullableClass.Builder arrayAndItemsNullableProp(List<Object> arrayAndItemsNullableProp) {
+      this.instance.arrayAndItemsNullableProp = JsonNullable.<List<Object>>of(arrayAndItemsNullableProp);
+      return this;
+    }
+    public NullableClass.Builder arrayAndItemsNullableProp(JsonNullable<List<Object>> arrayAndItemsNullableProp) {
+      this.instance.arrayAndItemsNullableProp = arrayAndItemsNullableProp;
+      return this;
+    }
+    public NullableClass.Builder arrayItemsNullable(List<Object> arrayItemsNullable) {
+      this.instance.arrayItemsNullable = arrayItemsNullable;
+      return this;
+    }
+    public NullableClass.Builder objectNullableProp(Map<String, Object> objectNullableProp) {
+      this.instance.objectNullableProp = JsonNullable.<Map<String, Object>>of(objectNullableProp);
+      return this;
+    }
+    public NullableClass.Builder objectNullableProp(JsonNullable<Map<String, Object>> objectNullableProp) {
+      this.instance.objectNullableProp = objectNullableProp;
+      return this;
+    }
+    public NullableClass.Builder objectAndItemsNullableProp(Map<String, Object> objectAndItemsNullableProp) {
+      this.instance.objectAndItemsNullableProp = JsonNullable.<Map<String, Object>>of(objectAndItemsNullableProp);
+      return this;
+    }
+    public NullableClass.Builder objectAndItemsNullableProp(JsonNullable<Map<String, Object>> objectAndItemsNullableProp) {
+      this.instance.objectAndItemsNullableProp = objectAndItemsNullableProp;
+      return this;
+    }
+    public NullableClass.Builder objectItemsNullable(Map<String, Object> objectItemsNullable) {
+      this.instance.objectItemsNullable = objectItemsNullable;
+      return this;
+    }
+
+
+    /**
+    * returns a built NullableClass instance.
+    *
+    * The builder is not reusable.
+    */
+    public NullableClass build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static NullableClass.Builder builder() {
+    return new NullableClass.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public NullableClass.Builder toBuilder() {
+    return new NullableClass.Builder()
+      .integerProp(getIntegerProp())
+      .numberProp(getNumberProp())
+      .booleanProp(getBooleanProp())
+      .stringProp(getStringProp())
+      .dateProp(getDateProp())
+      .datetimeProp(getDatetimeProp())
+      .arrayNullableProp(getArrayNullableProp())
+      .arrayAndItemsNullableProp(getArrayAndItemsNullableProp())
+      .arrayItemsNullable(getArrayItemsNullable())
+      .objectNullableProp(getObjectNullableProp())
+      .objectAndItemsNullableProp(getObjectAndItemsNullableProp())
+      .objectItemsNullable(getObjectItemsNullable());
+  }
+
 }
 

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

@@ -147,5 +147,59 @@ public class NumberOnly {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private NumberOnly instance;
+
+    public Builder() {
+      this(new NumberOnly());
+    }
+
+    protected Builder(NumberOnly instance) {
+      this.instance = instance;
+    }
+
+    public NumberOnly.Builder justNumber(BigDecimal justNumber) {
+      this.instance.justNumber = justNumber;
+      return this;
+    }
+
+
+    /**
+    * returns a built NumberOnly instance.
+    *
+    * The builder is not reusable.
+    */
+    public NumberOnly build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static NumberOnly.Builder builder() {
+    return new NumberOnly.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public NumberOnly.Builder toBuilder() {
+    return new NumberOnly.Builder()
+      .justNumber(getJustNumber());
+  }
+
 }
 

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

@@ -276,5 +276,74 @@ public class ObjectWithDeprecatedFields {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private ObjectWithDeprecatedFields instance;
+
+    public Builder() {
+      this(new ObjectWithDeprecatedFields());
+    }
+
+    protected Builder(ObjectWithDeprecatedFields instance) {
+      this.instance = instance;
+    }
+
+    public ObjectWithDeprecatedFields.Builder uuid(String uuid) {
+      this.instance.uuid = uuid;
+      return this;
+    }
+    public ObjectWithDeprecatedFields.Builder id(BigDecimal id) {
+      this.instance.id = id;
+      return this;
+    }
+    public ObjectWithDeprecatedFields.Builder deprecatedRef(DeprecatedObject deprecatedRef) {
+      this.instance.deprecatedRef = deprecatedRef;
+      return this;
+    }
+    public ObjectWithDeprecatedFields.Builder bars(List<String> bars) {
+      this.instance.bars = bars;
+      return this;
+    }
+
+
+    /**
+    * returns a built ObjectWithDeprecatedFields instance.
+    *
+    * The builder is not reusable.
+    */
+    public ObjectWithDeprecatedFields build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static ObjectWithDeprecatedFields.Builder builder() {
+    return new ObjectWithDeprecatedFields.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public ObjectWithDeprecatedFields.Builder toBuilder() {
+    return new ObjectWithDeprecatedFields.Builder()
+      .uuid(getUuid())
+      .id(getId())
+      .deprecatedRef(getDeprecatedRef())
+      .bars(getBars());
+  }
+
 }
 

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

@@ -364,5 +364,84 @@ public class Order {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private Order instance;
+
+    public Builder() {
+      this(new Order());
+    }
+
+    protected Builder(Order instance) {
+      this.instance = instance;
+    }
+
+    public Order.Builder id(Long id) {
+      this.instance.id = id;
+      return this;
+    }
+    public Order.Builder petId(Long petId) {
+      this.instance.petId = petId;
+      return this;
+    }
+    public Order.Builder quantity(Integer quantity) {
+      this.instance.quantity = quantity;
+      return this;
+    }
+    public Order.Builder shipDate(OffsetDateTime shipDate) {
+      this.instance.shipDate = shipDate;
+      return this;
+    }
+    public Order.Builder status(StatusEnum status) {
+      this.instance.status = status;
+      return this;
+    }
+    public Order.Builder complete(Boolean complete) {
+      this.instance.complete = complete;
+      return this;
+    }
+
+
+    /**
+    * returns a built Order instance.
+    *
+    * The builder is not reusable.
+    */
+    public Order build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static Order.Builder builder() {
+    return new Order.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public Order.Builder toBuilder() {
+    return new Order.Builder()
+      .id(getId())
+      .petId(getPetId())
+      .quantity(getQuantity())
+      .shipDate(getShipDate())
+      .status(getStatus())
+      .complete(getComplete());
+  }
+
 }
 

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

@@ -219,5 +219,69 @@ public class OuterComposite {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private OuterComposite instance;
+
+    public Builder() {
+      this(new OuterComposite());
+    }
+
+    protected Builder(OuterComposite instance) {
+      this.instance = instance;
+    }
+
+    public OuterComposite.Builder myNumber(BigDecimal myNumber) {
+      this.instance.myNumber = myNumber;
+      return this;
+    }
+    public OuterComposite.Builder myString(String myString) {
+      this.instance.myString = myString;
+      return this;
+    }
+    public OuterComposite.Builder myBoolean(Boolean myBoolean) {
+      this.instance.myBoolean = myBoolean;
+      return this;
+    }
+
+
+    /**
+    * returns a built OuterComposite instance.
+    *
+    * The builder is not reusable.
+    */
+    public OuterComposite build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static OuterComposite.Builder builder() {
+    return new OuterComposite.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public OuterComposite.Builder toBuilder() {
+    return new OuterComposite.Builder()
+      .myNumber(getMyNumber())
+      .myString(getMyString())
+      .myBoolean(getMyBoolean());
+  }
+
 }
 

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

@@ -143,5 +143,62 @@ static {
   mappings.put("ParentPet", ParentPet.class);
   JSON.registerDiscriminator(ParentPet.class, "pet_type", mappings);
 }
+
+    public static class Builder extends GrandparentAnimal.Builder {
+
+    private ParentPet instance;
+
+    public Builder() {
+      this(new ParentPet());
+    }
+
+    protected Builder(ParentPet instance) {
+      super(instance);
+      this.instance = instance;
+    }
+
+
+    public ParentPet.Builder petType(String petType) { // inherited: true
+      super.petType(petType);
+      return this;
+   }
+
+
+    /**
+    * returns a built ParentPet instance.
+    *
+    * The builder is not reusable.
+    */
+    public ParentPet build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        super.build();
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static ParentPet.Builder builder() {
+    return new ParentPet.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public ParentPet.Builder toBuilder() {
+    return new ParentPet.Builder()
+      .petType(getPetType());
+  }
+
 }
 

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

@@ -392,5 +392,84 @@ public class Pet {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private Pet instance;
+
+    public Builder() {
+      this(new Pet());
+    }
+
+    protected Builder(Pet instance) {
+      this.instance = instance;
+    }
+
+    public Pet.Builder id(Long id) {
+      this.instance.id = id;
+      return this;
+    }
+    public Pet.Builder category(Category category) {
+      this.instance.category = category;
+      return this;
+    }
+    public Pet.Builder name(String name) {
+      this.instance.name = name;
+      return this;
+    }
+    public Pet.Builder photoUrls(List<String> photoUrls) {
+      this.instance.photoUrls = photoUrls;
+      return this;
+    }
+    public Pet.Builder tags(List<Tag> tags) {
+      this.instance.tags = tags;
+      return this;
+    }
+    public Pet.Builder status(StatusEnum status) {
+      this.instance.status = status;
+      return this;
+    }
+
+
+    /**
+    * returns a built Pet instance.
+    *
+    * The builder is not reusable.
+    */
+    public Pet build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static Pet.Builder builder() {
+    return new Pet.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public Pet.Builder toBuilder() {
+    return new Pet.Builder()
+      .id(getId())
+      .category(getCategory())
+      .name(getName())
+      .photoUrls(getPhotoUrls())
+      .tags(getTags())
+      .status(getStatus());
+  }
+
 }
 

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

@@ -146,5 +146,59 @@ public class QuadrilateralInterface {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private QuadrilateralInterface instance;
+
+    public Builder() {
+      this(new QuadrilateralInterface());
+    }
+
+    protected Builder(QuadrilateralInterface instance) {
+      this.instance = instance;
+    }
+
+    public QuadrilateralInterface.Builder quadrilateralType(String quadrilateralType) {
+      this.instance.quadrilateralType = quadrilateralType;
+      return this;
+    }
+
+
+    /**
+    * returns a built QuadrilateralInterface instance.
+    *
+    * The builder is not reusable.
+    */
+    public QuadrilateralInterface build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static QuadrilateralInterface.Builder builder() {
+    return new QuadrilateralInterface.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public QuadrilateralInterface.Builder toBuilder() {
+    return new QuadrilateralInterface.Builder()
+      .quadrilateralType(getQuadrilateralType());
+  }
+
 }
 

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

@@ -180,5 +180,64 @@ public class ReadOnlyFirst {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private ReadOnlyFirst instance;
+
+    public Builder() {
+      this(new ReadOnlyFirst());
+    }
+
+    protected Builder(ReadOnlyFirst instance) {
+      this.instance = instance;
+    }
+
+    public ReadOnlyFirst.Builder bar(String bar) {
+      this.instance.bar = bar;
+      return this;
+    }
+    public ReadOnlyFirst.Builder baz(String baz) {
+      this.instance.baz = baz;
+      return this;
+    }
+
+
+    /**
+    * returns a built ReadOnlyFirst instance.
+    *
+    * The builder is not reusable.
+    */
+    public ReadOnlyFirst build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static ReadOnlyFirst.Builder builder() {
+    return new ReadOnlyFirst.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public ReadOnlyFirst.Builder toBuilder() {
+    return new ReadOnlyFirst.Builder()
+      .bar(getBar())
+      .baz(getBaz());
+  }
+
 }
 

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

@@ -182,5 +182,64 @@ public class ScaleneTriangle {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private ScaleneTriangle instance;
+
+    public Builder() {
+      this(new ScaleneTriangle());
+    }
+
+    protected Builder(ScaleneTriangle instance) {
+      this.instance = instance;
+    }
+
+    public ScaleneTriangle.Builder shapeType(String shapeType) {
+      this.instance.shapeType = shapeType;
+      return this;
+    }
+    public ScaleneTriangle.Builder triangleType(String triangleType) {
+      this.instance.triangleType = triangleType;
+      return this;
+    }
+
+
+    /**
+    * returns a built ScaleneTriangle instance.
+    *
+    * The builder is not reusable.
+    */
+    public ScaleneTriangle build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static ScaleneTriangle.Builder builder() {
+    return new ScaleneTriangle.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public ScaleneTriangle.Builder toBuilder() {
+    return new ScaleneTriangle.Builder()
+      .shapeType(getShapeType())
+      .triangleType(getTriangleType());
+  }
+
 }
 

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

@@ -146,5 +146,59 @@ public class ShapeInterface {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private ShapeInterface instance;
+
+    public Builder() {
+      this(new ShapeInterface());
+    }
+
+    protected Builder(ShapeInterface instance) {
+      this.instance = instance;
+    }
+
+    public ShapeInterface.Builder shapeType(String shapeType) {
+      this.instance.shapeType = shapeType;
+      return this;
+    }
+
+
+    /**
+    * returns a built ShapeInterface instance.
+    *
+    * The builder is not reusable.
+    */
+    public ShapeInterface build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static ShapeInterface.Builder builder() {
+    return new ShapeInterface.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public ShapeInterface.Builder toBuilder() {
+    return new ShapeInterface.Builder()
+      .shapeType(getShapeType());
+  }
+
 }
 

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

@@ -182,5 +182,64 @@ public class SimpleQuadrilateral {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private SimpleQuadrilateral instance;
+
+    public Builder() {
+      this(new SimpleQuadrilateral());
+    }
+
+    protected Builder(SimpleQuadrilateral instance) {
+      this.instance = instance;
+    }
+
+    public SimpleQuadrilateral.Builder shapeType(String shapeType) {
+      this.instance.shapeType = shapeType;
+      return this;
+    }
+    public SimpleQuadrilateral.Builder quadrilateralType(String quadrilateralType) {
+      this.instance.quadrilateralType = quadrilateralType;
+      return this;
+    }
+
+
+    /**
+    * returns a built SimpleQuadrilateral instance.
+    *
+    * The builder is not reusable.
+    */
+    public SimpleQuadrilateral build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static SimpleQuadrilateral.Builder builder() {
+    return new SimpleQuadrilateral.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public SimpleQuadrilateral.Builder toBuilder() {
+    return new SimpleQuadrilateral.Builder()
+      .shapeType(getShapeType())
+      .quadrilateralType(getQuadrilateralType());
+  }
+
 }
 

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

@@ -182,5 +182,64 @@ public class SpecialModelName {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private SpecialModelName instance;
+
+    public Builder() {
+      this(new SpecialModelName());
+    }
+
+    protected Builder(SpecialModelName instance) {
+      this.instance = instance;
+    }
+
+    public SpecialModelName.Builder $specialPropertyName(Long $specialPropertyName) {
+      this.instance.$specialPropertyName = $specialPropertyName;
+      return this;
+    }
+    public SpecialModelName.Builder specialModelName(String specialModelName) {
+      this.instance.specialModelName = specialModelName;
+      return this;
+    }
+
+
+    /**
+    * returns a built SpecialModelName instance.
+    *
+    * The builder is not reusable.
+    */
+    public SpecialModelName build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static SpecialModelName.Builder builder() {
+    return new SpecialModelName.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public SpecialModelName.Builder toBuilder() {
+    return new SpecialModelName.Builder()
+      .$specialPropertyName(get$SpecialPropertyName())
+      .specialModelName(getSpecialModelName());
+  }
+
 }
 

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

@@ -182,5 +182,64 @@ public class Tag {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private Tag instance;
+
+    public Builder() {
+      this(new Tag());
+    }
+
+    protected Builder(Tag instance) {
+      this.instance = instance;
+    }
+
+    public Tag.Builder id(Long id) {
+      this.instance.id = id;
+      return this;
+    }
+    public Tag.Builder name(String name) {
+      this.instance.name = name;
+      return this;
+    }
+
+
+    /**
+    * returns a built Tag instance.
+    *
+    * The builder is not reusable.
+    */
+    public Tag build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static Tag.Builder builder() {
+    return new Tag.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public Tag.Builder toBuilder() {
+    return new Tag.Builder()
+      .id(getId())
+      .name(getName());
+  }
+
 }
 

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

@@ -199,5 +199,59 @@ public class TestInlineFreeformAdditionalPropertiesRequest extends HashMap<Strin
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private TestInlineFreeformAdditionalPropertiesRequest instance;
+
+    public Builder() {
+      this(new TestInlineFreeformAdditionalPropertiesRequest());
+    }
+
+    protected Builder(TestInlineFreeformAdditionalPropertiesRequest instance) {
+      this.instance = instance;
+    }
+
+    public TestInlineFreeformAdditionalPropertiesRequest.Builder someProperty(String someProperty) {
+      this.instance.someProperty = someProperty;
+      return this;
+    }
+
+
+    /**
+    * returns a built TestInlineFreeformAdditionalPropertiesRequest instance.
+    *
+    * The builder is not reusable.
+    */
+    public TestInlineFreeformAdditionalPropertiesRequest build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static TestInlineFreeformAdditionalPropertiesRequest.Builder builder() {
+    return new TestInlineFreeformAdditionalPropertiesRequest.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public TestInlineFreeformAdditionalPropertiesRequest.Builder toBuilder() {
+    return new TestInlineFreeformAdditionalPropertiesRequest.Builder()
+      .someProperty(getSomeProperty());
+  }
+
 }
 

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

@@ -146,5 +146,59 @@ public class TriangleInterface {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private TriangleInterface instance;
+
+    public Builder() {
+      this(new TriangleInterface());
+    }
+
+    protected Builder(TriangleInterface instance) {
+      this.instance = instance;
+    }
+
+    public TriangleInterface.Builder triangleType(String triangleType) {
+      this.instance.triangleType = triangleType;
+      return this;
+    }
+
+
+    /**
+    * returns a built TriangleInterface instance.
+    *
+    * The builder is not reusable.
+    */
+    public TriangleInterface build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static TriangleInterface.Builder builder() {
+    return new TriangleInterface.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public TriangleInterface.Builder toBuilder() {
+    return new TriangleInterface.Builder()
+      .triangleType(getTriangleType());
+  }
+
 }
 

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

@@ -581,5 +581,126 @@ public class User {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private User instance;
+
+    public Builder() {
+      this(new User());
+    }
+
+    protected Builder(User instance) {
+      this.instance = instance;
+    }
+
+    public User.Builder id(Long id) {
+      this.instance.id = id;
+      return this;
+    }
+    public User.Builder username(String username) {
+      this.instance.username = username;
+      return this;
+    }
+    public User.Builder firstName(String firstName) {
+      this.instance.firstName = firstName;
+      return this;
+    }
+    public User.Builder lastName(String lastName) {
+      this.instance.lastName = lastName;
+      return this;
+    }
+    public User.Builder email(String email) {
+      this.instance.email = email;
+      return this;
+    }
+    public User.Builder password(String password) {
+      this.instance.password = password;
+      return this;
+    }
+    public User.Builder phone(String phone) {
+      this.instance.phone = phone;
+      return this;
+    }
+    public User.Builder userStatus(Integer userStatus) {
+      this.instance.userStatus = userStatus;
+      return this;
+    }
+    public User.Builder objectWithNoDeclaredProps(Object objectWithNoDeclaredProps) {
+      this.instance.objectWithNoDeclaredProps = objectWithNoDeclaredProps;
+      return this;
+    }
+    public User.Builder objectWithNoDeclaredPropsNullable(Object objectWithNoDeclaredPropsNullable) {
+      this.instance.objectWithNoDeclaredPropsNullable = JsonNullable.<Object>of(objectWithNoDeclaredPropsNullable);
+      return this;
+    }
+    public User.Builder objectWithNoDeclaredPropsNullable(JsonNullable<Object> objectWithNoDeclaredPropsNullable) {
+      this.instance.objectWithNoDeclaredPropsNullable = objectWithNoDeclaredPropsNullable;
+      return this;
+    }
+    public User.Builder anyTypeProp(Object anyTypeProp) {
+      this.instance.anyTypeProp = JsonNullable.<Object>of(anyTypeProp);
+      return this;
+    }
+    public User.Builder anyTypeProp(JsonNullable<Object> anyTypeProp) {
+      this.instance.anyTypeProp = anyTypeProp;
+      return this;
+    }
+    public User.Builder anyTypePropNullable(Object anyTypePropNullable) {
+      this.instance.anyTypePropNullable = JsonNullable.<Object>of(anyTypePropNullable);
+      return this;
+    }
+    public User.Builder anyTypePropNullable(JsonNullable<Object> anyTypePropNullable) {
+      this.instance.anyTypePropNullable = anyTypePropNullable;
+      return this;
+    }
+
+
+    /**
+    * returns a built User instance.
+    *
+    * The builder is not reusable.
+    */
+    public User build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static User.Builder builder() {
+    return new User.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public User.Builder toBuilder() {
+    return new User.Builder()
+      .id(getId())
+      .username(getUsername())
+      .firstName(getFirstName())
+      .lastName(getLastName())
+      .email(getEmail())
+      .password(getPassword())
+      .phone(getPhone())
+      .userStatus(getUserStatus())
+      .objectWithNoDeclaredProps(getObjectWithNoDeclaredProps())
+      .objectWithNoDeclaredPropsNullable(getObjectWithNoDeclaredPropsNullable())
+      .anyTypeProp(getAnyTypeProp())
+      .anyTypePropNullable(getAnyTypePropNullable());
+  }
+
 }
 

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

@@ -218,5 +218,69 @@ public class Whale {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private Whale instance;
+
+    public Builder() {
+      this(new Whale());
+    }
+
+    protected Builder(Whale instance) {
+      this.instance = instance;
+    }
+
+    public Whale.Builder hasBaleen(Boolean hasBaleen) {
+      this.instance.hasBaleen = hasBaleen;
+      return this;
+    }
+    public Whale.Builder hasTeeth(Boolean hasTeeth) {
+      this.instance.hasTeeth = hasTeeth;
+      return this;
+    }
+    public Whale.Builder className(String className) {
+      this.instance.className = className;
+      return this;
+    }
+
+
+    /**
+    * returns a built Whale instance.
+    *
+    * The builder is not reusable.
+    */
+    public Whale build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static Whale.Builder builder() {
+    return new Whale.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public Whale.Builder toBuilder() {
+    return new Whale.Builder()
+      .hasBaleen(getHasBaleen())
+      .hasTeeth(getHasTeeth())
+      .className(getClassName());
+  }
+
 }
 

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

@@ -272,5 +272,64 @@ public class Zebra extends HashMap<String, Object> {
 
     return joiner.toString();
   }
+
+    public static class Builder {
+
+    private Zebra instance;
+
+    public Builder() {
+      this(new Zebra());
+    }
+
+    protected Builder(Zebra instance) {
+      this.instance = instance;
+    }
+
+    public Zebra.Builder type(TypeEnum type) {
+      this.instance.type = type;
+      return this;
+    }
+    public Zebra.Builder className(String className) {
+      this.instance.className = className;
+      return this;
+    }
+
+
+    /**
+    * returns a built Zebra instance.
+    *
+    * The builder is not reusable.
+    */
+    public Zebra build() {
+      try {
+        return this.instance;
+      } finally {
+        // ensure that this.instance is not reused
+        this.instance = null;
+      }
+    }
+
+    @Override
+    public String toString() {
+      return getClass() + "=(" + instance + ")";
+    }
+  }
+
+  /**
+  * Create a builder with no initialized field.
+  */
+  public static Zebra.Builder builder() {
+    return new Zebra.Builder();
+  }
+
+  /**
+  * Create a builder with a shallow copy of this instance.
+  */
+  public Zebra.Builder toBuilder() {
+    return new Zebra.Builder()
+      .type(getType())
+      .className(getClassName());
+  }
+
 }