see https://github.com/OpenAPITools/openapi-generator/pull/19614

pr19614.diff

diff --git a/src/main/java/org/openapitools/client/model/Animal.java b/src/main/java/org/openapitools/client/model/Animal.java
index 5f33e7f..d2f8fe6 100644
--- a/src/main/java/org/openapitools/client/model/Animal.java
+++ b/src/main/java/org/openapitools/client/model/Animal.java
@@ -108,13 +108,13 @@ public class Animal {
 
   public static final String SERIALIZED_NAME_PET_TYPE = "petType";
   @SerializedName(SERIALIZED_NAME_PET_TYPE)
-  @javax.annotation.Nonnull
   protected PetTypeEnum petType;
 
   public Animal() {
+
   }
 
-  public Animal petType(@javax.annotation.Nonnull PetTypeEnum petType) {
+  public Animal petType(PetTypeEnum petType) {
     this.petType = petType;
     return this;
   }
@@ -128,7 +128,7 @@ public class Animal {
     return petType;
   }
 
-  public void setPetType(@javax.annotation.Nonnull PetTypeEnum petType) {
+  public void setPetType(PetTypeEnum petType) {
     this.petType = petType;
   }
 
diff --git a/src/main/java/org/openapitools/client/model/CargoVan.java b/src/main/java/org/openapitools/client/model/CargoVan.java
index a2d483f..96deb12 100644
--- a/src/main/java/org/openapitools/client/model/CargoVan.java
+++ b/src/main/java/org/openapitools/client/model/CargoVan.java
@@ -54,14 +54,15 @@ import org.openapitools.client.JSON;
 public class CargoVan extends Car {
   public static final String SERIALIZED_NAME_CAR_TYPE = "carType";
   @SerializedName(SERIALIZED_NAME_CAR_TYPE)
-  @javax.annotation.Nonnull
-  protected CarType carType;
+  protected CarType carType = CarType.CARGO_VAN;
 
   public CargoVan() {
-    this.carType = this.getClass().getSimpleName();
+
+    this.carType = CarType.CARGO_VAN;
+
   }
 
-  public CargoVan carType(@javax.annotation.Nonnull CarType carType) {
+  public CargoVan carType(CarType carType) {
     this.carType = carType;
     return this;
   }
@@ -75,7 +76,7 @@ public class CargoVan extends Car {
     return carType;
   }
 
-  public void setCarType(@javax.annotation.Nonnull CarType carType) {
+  public void setCarType(CarType carType) {
     this.carType = carType;
   }
 
diff --git a/src/main/java/org/openapitools/client/model/Cat.java b/src/main/java/org/openapitools/client/model/Cat.java
index 1fcdd54..847d3ac 100644
--- a/src/main/java/org/openapitools/client/model/Cat.java
+++ b/src/main/java/org/openapitools/client/model/Cat.java
@@ -53,14 +53,15 @@ import org.openapitools.client.JSON;
 public class Cat extends Animal {
   public static final String SERIALIZED_NAME_MEOW = "meow";
   @SerializedName(SERIALIZED_NAME_MEOW)
-  @javax.annotation.Nullable
   private String meow;
 
   public Cat() {
-    this.petType = this.getClass().getSimpleName();
+
+    this.petType = PetTypeEnum.CATTY;
+
   }
 
-  public Cat meow(@javax.annotation.Nullable String meow) {
+  public Cat meow(String meow) {
     this.meow = meow;
     return this;
   }
@@ -74,7 +75,7 @@ public class Cat extends Animal {
     return meow;
   }
 
-  public void setMeow(@javax.annotation.Nullable String meow) {
+  public void setMeow(String meow) {
     this.meow = meow;
   }
 
diff --git a/src/main/java/org/openapitools/client/model/Chameleon.java b/src/main/java/org/openapitools/client/model/Chameleon.java
index b1ce86c..54c7f52 100644
--- a/src/main/java/org/openapitools/client/model/Chameleon.java
+++ b/src/main/java/org/openapitools/client/model/Chameleon.java
@@ -53,14 +53,15 @@ import org.openapitools.client.JSON;
 public class Chameleon extends Animal {
   public static final String SERIALIZED_NAME_CURRENT_COLOR = "currentColor";
   @SerializedName(SERIALIZED_NAME_CURRENT_COLOR)
-  @javax.annotation.Nullable
   private String currentColor;
 
   public Chameleon() {
-    this.petType = this.getClass().getSimpleName();
+
+    this.petType = PetTypeEnum.CAMO;
+
   }
 
-  public Chameleon currentColor(@javax.annotation.Nullable String currentColor) {
+  public Chameleon currentColor(String currentColor) {
     this.currentColor = currentColor;
     return this;
   }
@@ -74,7 +75,7 @@ public class Chameleon extends Animal {
     return currentColor;
   }
 
-  public void setCurrentColor(@javax.annotation.Nullable String currentColor) {
+  public void setCurrentColor(String currentColor) {
     this.currentColor = currentColor;
   }
 
diff --git a/src/main/java/org/openapitools/client/model/Dog.java b/src/main/java/org/openapitools/client/model/Dog.java
index 40fcbf9..c0bc862 100644
--- a/src/main/java/org/openapitools/client/model/Dog.java
+++ b/src/main/java/org/openapitools/client/model/Dog.java
@@ -53,14 +53,15 @@ import org.openapitools.client.JSON;
 public class Dog extends Animal {
   public static final String SERIALIZED_NAME_BARK = "bark";
   @SerializedName(SERIALIZED_NAME_BARK)
-  @javax.annotation.Nullable
   private String bark;
 
   public Dog() {
-    this.petType = this.getClass().getSimpleName();
+
+    this.petType = PetTypeEnum.DOG;
+
   }
 
-  public Dog bark(@javax.annotation.Nullable String bark) {
+  public Dog bark(String bark) {
     this.bark = bark;
     return this;
   }
@@ -74,7 +75,7 @@ public class Dog extends Animal {
     return bark;
   }
 
-  public void setBark(@javax.annotation.Nullable String bark) {
+  public void setBark(String bark) {
     this.bark = bark;
   }
 
diff --git a/src/main/java/org/openapitools/client/model/Gecko.java b/src/main/java/org/openapitools/client/model/Gecko.java
index 311f65a..d9a5f6a 100644
--- a/src/main/java/org/openapitools/client/model/Gecko.java
+++ b/src/main/java/org/openapitools/client/model/Gecko.java
@@ -53,14 +53,15 @@ import org.openapitools.client.JSON;
 public class Gecko extends Animal {
   public static final String SERIALIZED_NAME_LOVES_ROCKS = "lovesRocks";
   @SerializedName(SERIALIZED_NAME_LOVES_ROCKS)
-  @javax.annotation.Nullable
   private String lovesRocks;
 
   public Gecko() {
-    this.petType = this.getClass().getSimpleName();
+
+    this.petType = PetTypeEnum.GECKO;
+
   }
 
-  public Gecko lovesRocks(@javax.annotation.Nullable String lovesRocks) {
+  public Gecko lovesRocks(String lovesRocks) {
     this.lovesRocks = lovesRocks;
     return this;
   }
@@ -74,7 +75,7 @@ public class Gecko extends Animal {
     return lovesRocks;
   }
 
-  public void setLovesRocks(@javax.annotation.Nullable String lovesRocks) {
+  public void setLovesRocks(String lovesRocks) {
     this.lovesRocks = lovesRocks;
   }
 
diff --git a/src/main/java/org/openapitools/client/model/Lizard.java b/src/main/java/org/openapitools/client/model/Lizard.java
index ea14f3f..c82aa89 100644
--- a/src/main/java/org/openapitools/client/model/Lizard.java
+++ b/src/main/java/org/openapitools/client/model/Lizard.java
@@ -209,7 +209,6 @@ public class Lizard extends AbstractOpenApiSchema {
     public Gecko getGecko() throws ClassCastException {
         return (Gecko)super.getActualInstance();
     }
-
     /**
      * Get the actual instance of `Chameleon`. If the actual instance is not `Chameleon`,
      * the ClassCastException will be thrown.
diff --git a/src/main/java/org/openapitools/client/model/MiniVan.java b/src/main/java/org/openapitools/client/model/MiniVan.java
index 995d771..2647b16 100644
--- a/src/main/java/org/openapitools/client/model/MiniVan.java
+++ b/src/main/java/org/openapitools/client/model/MiniVan.java
@@ -54,14 +54,15 @@ import org.openapitools.client.JSON;
 public class MiniVan extends Car {
   public static final String SERIALIZED_NAME_CAR_TYPE = "carType";
   @SerializedName(SERIALIZED_NAME_CAR_TYPE)
-  @javax.annotation.Nonnull
-  protected CarType carType;
+  protected CarType carType = CarType.MINI_VAN;
 
   public MiniVan() {
-    this.carType = this.getClass().getSimpleName();
+
+    this.carType = CarType.MINI_VAN;
+
   }
 
-  public MiniVan carType(@javax.annotation.Nonnull CarType carType) {
+  public MiniVan carType(CarType carType) {
     this.carType = carType;
     return this;
   }
@@ -75,7 +76,7 @@ public class MiniVan extends Car {
     return carType;
   }
 
-  public void setCarType(@javax.annotation.Nonnull CarType carType) {
+  public void setCarType(CarType carType) {
     this.carType = carType;
   }
 
diff --git a/src/main/java/org/openapitools/client/model/SUV.java b/src/main/java/org/openapitools/client/model/SUV.java
index 29d9adb..b142cc0 100644
--- a/src/main/java/org/openapitools/client/model/SUV.java
+++ b/src/main/java/org/openapitools/client/model/SUV.java
@@ -53,7 +53,9 @@ import org.openapitools.client.JSON;
 @javax.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen", comments = "Generator version: unset")
 public class SUV extends Truck {
   public SUV() {
-    this.carType = this.getClass().getSimpleName();
+
+    this.carType = CarType.SUV;
+
   }
 
 
diff --git a/src/main/java/org/openapitools/client/model/Sedan.java b/src/main/java/org/openapitools/client/model/Sedan.java
index f73c5df..c435cdc 100644
--- a/src/main/java/org/openapitools/client/model/Sedan.java
+++ b/src/main/java/org/openapitools/client/model/Sedan.java
@@ -54,14 +54,15 @@ import org.openapitools.client.JSON;
 public class Sedan extends Car {
   public static final String SERIALIZED_NAME_CAR_TYPE = "carType";
   @SerializedName(SERIALIZED_NAME_CAR_TYPE)
-  @javax.annotation.Nonnull
-  protected CarType carType;
+  protected CarType carType = CarType.SEDAN;
 
   public Sedan() {
-    this.carType = this.getClass().getSimpleName();
+
+    this.carType = CarType.SEDAN;
+
   }
 
-  public Sedan carType(@javax.annotation.Nonnull CarType carType) {
+  public Sedan carType(CarType carType) {
     this.carType = carType;
     return this;
   }
@@ -75,7 +76,7 @@ public class Sedan extends Car {
     return carType;
   }
 
-  public void setCarType(@javax.annotation.Nonnull CarType carType) {
+  public void setCarType(CarType carType) {
     this.carType = carType;
   }
 
diff --git a/src/main/java/org/openapitools/client/model/Truck.java b/src/main/java/org/openapitools/client/model/Truck.java
index 4d7d794..0c38077 100644
--- a/src/main/java/org/openapitools/client/model/Truck.java
+++ b/src/main/java/org/openapitools/client/model/Truck.java
@@ -54,14 +54,15 @@ import org.openapitools.client.JSON;
 public class Truck extends Car {
   public static final String SERIALIZED_NAME_CAR_TYPE = "carType";
   @SerializedName(SERIALIZED_NAME_CAR_TYPE)
-  @javax.annotation.Nonnull
-  protected CarType carType;
+  protected CarType carType = CarType.TRUCK;
 
   public Truck() {
-    this.carType = this.getClass().getSimpleName();
+
+    this.carType = CarType.TRUCK;
+
   }
 
-  public Truck carType(@javax.annotation.Nonnull CarType carType) {
+  public Truck carType(CarType carType) {
     this.carType = carType;
     return this;
   }
@@ -75,7 +76,7 @@ public class Truck extends Car {
     return carType;
   }
 
-  public void setCarType(@javax.annotation.Nonnull CarType carType) {
+  public void setCarType(CarType carType) {
     this.carType = carType;
   }
 
diff --git a/src/main/java/org/openapitools/client/model/Van.java b/src/main/java/org/openapitools/client/model/Van.java
index 3eda4b3..5c7195b 100644
--- a/src/main/java/org/openapitools/client/model/Van.java
+++ b/src/main/java/org/openapitools/client/model/Van.java
@@ -210,7 +210,6 @@ public class Van extends AbstractOpenApiSchema {
     public MiniVan getMiniVan() throws ClassCastException {
         return (MiniVan)super.getActualInstance();
     }
-
     /**
      * Get the actual instance of `CargoVan`. If the actual instance is not `CargoVan`,
      * the ClassCastException will be thrown.