diff --git a/modules/openapi-generator/src/main/resources/csharp-netcore/AbstractOpenAPISchema.mustache b/modules/openapi-generator/src/main/resources/csharp-netcore/AbstractOpenAPISchema.mustache
index bd65e7144bb..a59359813d2 100644
--- a/modules/openapi-generator/src/main/resources/csharp-netcore/AbstractOpenAPISchema.mustache
+++ b/modules/openapi-generator/src/main/resources/csharp-netcore/AbstractOpenAPISchema.mustache
@@ -14,7 +14,7 @@ namespace {{packageName}}.{{modelPackage}}
         /// <summary>
         ///  Custom JSON serializer
         /// </summary>
-        protected readonly JsonSerializerSettings _serializerSettings = new JsonSerializerSettings
+        static public readonly JsonSerializerSettings SerializerSettings = new JsonSerializerSettings
         {
             // OpenAPI generated types generally hide default constructors.
             ConstructorHandling = ConstructorHandling.AllowNonPublicDefaultConstructor,
diff --git a/modules/openapi-generator/src/main/resources/csharp-netcore/modelOneOf.mustache b/modules/openapi-generator/src/main/resources/csharp-netcore/modelOneOf.mustache
index a12e0337af0..36650cf9ed5 100644
--- a/modules/openapi-generator/src/main/resources/csharp-netcore/modelOneOf.mustache
+++ b/modules/openapi-generator/src/main/resources/csharp-netcore/modelOneOf.mustache
@@ -4,6 +4,7 @@
     [DataContract(Name = "{{{name}}}")]
     {{>visibility}} partial class {{classname}} : AbstractOpenAPISchema, {{#parent}}{{{parent}}}, {{/parent}}IEquatable<{{classname}}>{{#validatable}}, IValidatableObject{{/validatable}}
     {
+        {{#isNullable}}
         /// <summary>
         /// Initializes a new instance of the <see cref="{{classname}}" /> class.
         /// </summary>
@@ -13,6 +14,7 @@
             this.SchemaType= "oneOf";
         }
 
+        {{/isNullable}}
         {{#oneOf}}
         /// <summary>
         /// Initializes a new instance of the <see cref="{{classname}}" /> class
@@ -85,7 +87,7 @@
         /// <returns>JSON string presentation of the object</returns>
         public override string ToJson()
         {
-            return JsonConvert.SerializeObject(this.ActualInstance, _serializerSettings);
+            return JsonConvert.SerializeObject(this.ActualInstance, {{classname}}.SerializerSettings);
         }
 
         /// <summary>
@@ -95,7 +97,7 @@
         /// <returns>An instance of {{classname}}</returns>
         public static {{classname}} FromJson(string jsonString)
         {
-            {{classname}} new{{classname}} = new {{classname}}();
+            {{classname}} new{{classname}} = null;
             {{#useOneOfDiscriminatorLookup}}
             {{#discriminator}}
 
@@ -104,11 +106,11 @@
             {
                 {{#mappedModels}}
                 case "{{{mappingName}}}":
-                    new{{classname}}.ActualInstance = JsonConvert.DeserializeObject<{{{modelName}}}>(jsonString, new{{classname}}._serializerSettings);
+                    new{{classname}} = new {{classname}}(JsonConvert.DeserializeObject<{{{modelName}}}>(jsonString, {{classname}}.SerializerSettings));
                     return new{{classname}};
                 {{/mappedModels}}
                 default:
-                    System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `%s` for {{classname}}. Possible values:{{#mappedModels}} {{{mappingName}}}{{/mappedModels}}", discriminatorValue));
+                    System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `{0}` for {{classname}}. Possible values:{{#mappedModels}} {{{mappingName}}}{{/mappedModels}}", discriminatorValue));
                     break;
             }
 
@@ -120,14 +122,14 @@
 
             try
             {
-                new{{classname}}.ActualInstance = JsonConvert.DeserializeObject<{{{.}}}>(jsonString, new{{classname}}._serializerSettings);
+                new{{classname}} = new {{classname}}(JsonConvert.DeserializeObject<{{{.}}}>(jsonString, {{classname}}.SerializerSettings));
                 matchedTypes.Add("{{{.}}}");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into {{{.}}}: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into {{{.}}}: {1}", jsonString, exception.ToString()));
             }
             {{/oneOf}}
 
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools.Test/JSONComposedSchemaTests.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools.Test/JSONComposedSchemaTests.cs
index 80b3a5bf59f..7995b0a8289 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools.Test/JSONComposedSchemaTests.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools.Test/JSONComposedSchemaTests.cs
@@ -68,7 +68,7 @@ namespace Org.OpenAPITools.Test
             t.Name = "Something";
 
             Fruit f1 = new Fruit(a);
-            Fruit f2 = new Fruit(a);
+            Fruit f2 = new Fruit(b);
 
             f1.ActualInstance = b;
             f2.ActualInstance = a;
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/AbstractOpenAPISchema.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/AbstractOpenAPISchema.cs
index 2d3fda31aee..b37dea7796d 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/AbstractOpenAPISchema.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/AbstractOpenAPISchema.cs
@@ -22,7 +22,7 @@ namespace Org.OpenAPITools.Model
         /// <summary>
         ///  Custom JSON serializer
         /// </summary>
-        protected readonly JsonSerializerSettings _serializerSettings = new JsonSerializerSettings
+        static public readonly JsonSerializerSettings SerializerSettings = new JsonSerializerSettings
         {
             // OpenAPI generated types generally hide default constructors.
             ConstructorHandling = ConstructorHandling.AllowNonPublicDefaultConstructor,
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Fruit.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Fruit.cs
index ee556c02c61..81874287d74 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Fruit.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Fruit.cs
@@ -32,15 +32,6 @@ namespace Org.OpenAPITools.Model
     [DataContract(Name = "fruit")]
     public partial class Fruit : AbstractOpenAPISchema, IEquatable<Fruit>, IValidatableObject
     {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="Fruit" /> class.
-        /// </summary>
-        public Fruit()
-        {
-            this.IsNullable = true;
-            this.SchemaType= "oneOf";
-        }
-
         /// <summary>
         /// Initializes a new instance of the <see cref="Fruit" /> class
         /// with the <see cref="Apple" /> class
@@ -133,7 +124,7 @@ namespace Org.OpenAPITools.Model
         /// <returns>JSON string presentation of the object</returns>
         public override string ToJson()
         {
-            return JsonConvert.SerializeObject(this.ActualInstance, _serializerSettings);
+            return JsonConvert.SerializeObject(this.ActualInstance, Fruit.SerializerSettings);
         }
 
         /// <summary>
@@ -143,32 +134,32 @@ namespace Org.OpenAPITools.Model
         /// <returns>An instance of Fruit</returns>
         public static Fruit FromJson(string jsonString)
         {
-            Fruit newFruit = new Fruit();
+            Fruit newFruit = null;
             int match = 0;
             List<string> matchedTypes = new List<string>();
 
             try
             {
-                newFruit.ActualInstance = JsonConvert.DeserializeObject<Apple>(jsonString, newFruit._serializerSettings);
+                newFruit = new Fruit(JsonConvert.DeserializeObject<Apple>(jsonString, Fruit.SerializerSettings));
                 matchedTypes.Add("Apple");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into Apple: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into Apple: {1}", jsonString, exception.ToString()));
             }
 
             try
             {
-                newFruit.ActualInstance = JsonConvert.DeserializeObject<Banana>(jsonString, newFruit._serializerSettings);
+                newFruit = new Fruit(JsonConvert.DeserializeObject<Banana>(jsonString, Fruit.SerializerSettings));
                 matchedTypes.Add("Banana");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into Banana: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into Banana: {1}", jsonString, exception.ToString()));
             }
 
             if (match == 0)
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/FruitReq.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/FruitReq.cs
index 6e997adbd07..233db1a1fee 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/FruitReq.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/FruitReq.cs
@@ -133,7 +133,7 @@ namespace Org.OpenAPITools.Model
         /// <returns>JSON string presentation of the object</returns>
         public override string ToJson()
         {
-            return JsonConvert.SerializeObject(this.ActualInstance, _serializerSettings);
+            return JsonConvert.SerializeObject(this.ActualInstance, FruitReq.SerializerSettings);
         }
 
         /// <summary>
@@ -143,32 +143,32 @@ namespace Org.OpenAPITools.Model
         /// <returns>An instance of FruitReq</returns>
         public static FruitReq FromJson(string jsonString)
         {
-            FruitReq newFruitReq = new FruitReq();
+            FruitReq newFruitReq = null;
             int match = 0;
             List<string> matchedTypes = new List<string>();
 
             try
             {
-                newFruitReq.ActualInstance = JsonConvert.DeserializeObject<AppleReq>(jsonString, newFruitReq._serializerSettings);
+                newFruitReq = new FruitReq(JsonConvert.DeserializeObject<AppleReq>(jsonString, FruitReq.SerializerSettings));
                 matchedTypes.Add("AppleReq");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into AppleReq: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into AppleReq: {1}", jsonString, exception.ToString()));
             }
 
             try
             {
-                newFruitReq.ActualInstance = JsonConvert.DeserializeObject<BananaReq>(jsonString, newFruitReq._serializerSettings);
+                newFruitReq = new FruitReq(JsonConvert.DeserializeObject<BananaReq>(jsonString, FruitReq.SerializerSettings));
                 matchedTypes.Add("BananaReq");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into BananaReq: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into BananaReq: {1}", jsonString, exception.ToString()));
             }
 
             if (match == 0)
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Mammal.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Mammal.cs
index 88add0eabe1..6eddc2b0558 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Mammal.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Mammal.cs
@@ -33,15 +33,6 @@ namespace Org.OpenAPITools.Model
     [DataContract(Name = "mammal")]
     public partial class Mammal : AbstractOpenAPISchema, IEquatable<Mammal>, IValidatableObject
     {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="Mammal" /> class.
-        /// </summary>
-        public Mammal()
-        {
-            this.IsNullable = true;
-            this.SchemaType= "oneOf";
-        }
-
         /// <summary>
         /// Initializes a new instance of the <see cref="Mammal" /> class
         /// with the <see cref="Pig" /> class
@@ -160,7 +151,7 @@ namespace Org.OpenAPITools.Model
         /// <returns>JSON string presentation of the object</returns>
         public override string ToJson()
         {
-            return JsonConvert.SerializeObject(this.ActualInstance, _serializerSettings);
+            return JsonConvert.SerializeObject(this.ActualInstance, Mammal.SerializerSettings);
         }
 
         /// <summary>
@@ -170,22 +161,22 @@ namespace Org.OpenAPITools.Model
         /// <returns>An instance of Mammal</returns>
         public static Mammal FromJson(string jsonString)
         {
-            Mammal newMammal = new Mammal();
+            Mammal newMammal = null;
 
             string discriminatorValue = JObject.Parse(jsonString)["className"].ToString();
             switch (discriminatorValue)
             {
                 case "Pig":
-                    newMammal.ActualInstance = JsonConvert.DeserializeObject<Pig>(jsonString, newMammal._serializerSettings);
+                    newMammal = new Mammal(JsonConvert.DeserializeObject<Pig>(jsonString, Mammal.SerializerSettings));
                     return newMammal;
                 case "whale":
-                    newMammal.ActualInstance = JsonConvert.DeserializeObject<Whale>(jsonString, newMammal._serializerSettings);
+                    newMammal = new Mammal(JsonConvert.DeserializeObject<Whale>(jsonString, Mammal.SerializerSettings));
                     return newMammal;
                 case "zebra":
-                    newMammal.ActualInstance = JsonConvert.DeserializeObject<Zebra>(jsonString, newMammal._serializerSettings);
+                    newMammal = new Mammal(JsonConvert.DeserializeObject<Zebra>(jsonString, Mammal.SerializerSettings));
                     return newMammal;
                 default:
-                    System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `%s` for Mammal. Possible values: Pig whale zebra", discriminatorValue));
+                    System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `{0}` for Mammal. Possible values: Pig whale zebra", discriminatorValue));
                     break;
             }
 
@@ -194,38 +185,38 @@ namespace Org.OpenAPITools.Model
 
             try
             {
-                newMammal.ActualInstance = JsonConvert.DeserializeObject<Pig>(jsonString, newMammal._serializerSettings);
+                newMammal = new Mammal(JsonConvert.DeserializeObject<Pig>(jsonString, Mammal.SerializerSettings));
                 matchedTypes.Add("Pig");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into Pig: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into Pig: {1}", jsonString, exception.ToString()));
             }
 
             try
             {
-                newMammal.ActualInstance = JsonConvert.DeserializeObject<Whale>(jsonString, newMammal._serializerSettings);
+                newMammal = new Mammal(JsonConvert.DeserializeObject<Whale>(jsonString, Mammal.SerializerSettings));
                 matchedTypes.Add("Whale");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into Whale: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into Whale: {1}", jsonString, exception.ToString()));
             }
 
             try
             {
-                newMammal.ActualInstance = JsonConvert.DeserializeObject<Zebra>(jsonString, newMammal._serializerSettings);
+                newMammal = new Mammal(JsonConvert.DeserializeObject<Zebra>(jsonString, Mammal.SerializerSettings));
                 matchedTypes.Add("Zebra");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into Zebra: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into Zebra: {1}", jsonString, exception.ToString()));
             }
 
             if (match == 0)
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/NullableShape.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/NullableShape.cs
index 6b7003a52fb..a7ba225be9a 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/NullableShape.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/NullableShape.cs
@@ -134,7 +134,7 @@ namespace Org.OpenAPITools.Model
         /// <returns>JSON string presentation of the object</returns>
         public override string ToJson()
         {
-            return JsonConvert.SerializeObject(this.ActualInstance, _serializerSettings);
+            return JsonConvert.SerializeObject(this.ActualInstance, NullableShape.SerializerSettings);
         }
 
         /// <summary>
@@ -144,19 +144,19 @@ namespace Org.OpenAPITools.Model
         /// <returns>An instance of NullableShape</returns>
         public static NullableShape FromJson(string jsonString)
         {
-            NullableShape newNullableShape = new NullableShape();
+            NullableShape newNullableShape = null;
 
             string discriminatorValue = JObject.Parse(jsonString)["shapeType"].ToString();
             switch (discriminatorValue)
             {
                 case "Quadrilateral":
-                    newNullableShape.ActualInstance = JsonConvert.DeserializeObject<Quadrilateral>(jsonString, newNullableShape._serializerSettings);
+                    newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, NullableShape.SerializerSettings));
                     return newNullableShape;
                 case "Triangle":
-                    newNullableShape.ActualInstance = JsonConvert.DeserializeObject<Triangle>(jsonString, newNullableShape._serializerSettings);
+                    newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Triangle>(jsonString, NullableShape.SerializerSettings));
                     return newNullableShape;
                 default:
-                    System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `%s` for NullableShape. Possible values: Quadrilateral Triangle", discriminatorValue));
+                    System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `{0}` for NullableShape. Possible values: Quadrilateral Triangle", discriminatorValue));
                     break;
             }
 
@@ -165,26 +165,26 @@ namespace Org.OpenAPITools.Model
 
             try
             {
-                newNullableShape.ActualInstance = JsonConvert.DeserializeObject<Quadrilateral>(jsonString, newNullableShape._serializerSettings);
+                newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, NullableShape.SerializerSettings));
                 matchedTypes.Add("Quadrilateral");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into Quadrilateral: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into Quadrilateral: {1}", jsonString, exception.ToString()));
             }
 
             try
             {
-                newNullableShape.ActualInstance = JsonConvert.DeserializeObject<Triangle>(jsonString, newNullableShape._serializerSettings);
+                newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Triangle>(jsonString, NullableShape.SerializerSettings));
                 matchedTypes.Add("Triangle");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into Triangle: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into Triangle: {1}", jsonString, exception.ToString()));
             }
 
             if (match == 0)
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Pig.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Pig.cs
index ae6baa4019c..7f9f8d96a44 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Pig.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Pig.cs
@@ -33,15 +33,6 @@ namespace Org.OpenAPITools.Model
     [DataContract(Name = "Pig")]
     public partial class Pig : AbstractOpenAPISchema, IEquatable<Pig>, IValidatableObject
     {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="Pig" /> class.
-        /// </summary>
-        public Pig()
-        {
-            this.IsNullable = true;
-            this.SchemaType= "oneOf";
-        }
-
         /// <summary>
         /// Initializes a new instance of the <see cref="Pig" /> class
         /// with the <see cref="BasquePig" /> class
@@ -134,7 +125,7 @@ namespace Org.OpenAPITools.Model
         /// <returns>JSON string presentation of the object</returns>
         public override string ToJson()
         {
-            return JsonConvert.SerializeObject(this.ActualInstance, _serializerSettings);
+            return JsonConvert.SerializeObject(this.ActualInstance, Pig.SerializerSettings);
         }
 
         /// <summary>
@@ -144,19 +135,19 @@ namespace Org.OpenAPITools.Model
         /// <returns>An instance of Pig</returns>
         public static Pig FromJson(string jsonString)
         {
-            Pig newPig = new Pig();
+            Pig newPig = null;
 
             string discriminatorValue = JObject.Parse(jsonString)["className"].ToString();
             switch (discriminatorValue)
             {
                 case "BasquePig":
-                    newPig.ActualInstance = JsonConvert.DeserializeObject<BasquePig>(jsonString, newPig._serializerSettings);
+                    newPig = new Pig(JsonConvert.DeserializeObject<BasquePig>(jsonString, Pig.SerializerSettings));
                     return newPig;
                 case "DanishPig":
-                    newPig.ActualInstance = JsonConvert.DeserializeObject<DanishPig>(jsonString, newPig._serializerSettings);
+                    newPig = new Pig(JsonConvert.DeserializeObject<DanishPig>(jsonString, Pig.SerializerSettings));
                     return newPig;
                 default:
-                    System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `%s` for Pig. Possible values: BasquePig DanishPig", discriminatorValue));
+                    System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `{0}` for Pig. Possible values: BasquePig DanishPig", discriminatorValue));
                     break;
             }
 
@@ -165,26 +156,26 @@ namespace Org.OpenAPITools.Model
 
             try
             {
-                newPig.ActualInstance = JsonConvert.DeserializeObject<BasquePig>(jsonString, newPig._serializerSettings);
+                newPig = new Pig(JsonConvert.DeserializeObject<BasquePig>(jsonString, Pig.SerializerSettings));
                 matchedTypes.Add("BasquePig");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into BasquePig: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into BasquePig: {1}", jsonString, exception.ToString()));
             }
 
             try
             {
-                newPig.ActualInstance = JsonConvert.DeserializeObject<DanishPig>(jsonString, newPig._serializerSettings);
+                newPig = new Pig(JsonConvert.DeserializeObject<DanishPig>(jsonString, Pig.SerializerSettings));
                 matchedTypes.Add("DanishPig");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into DanishPig: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into DanishPig: {1}", jsonString, exception.ToString()));
             }
 
             if (match == 0)
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Quadrilateral.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Quadrilateral.cs
index 80b27aeaeb2..bba3de0f2fc 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Quadrilateral.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Quadrilateral.cs
@@ -33,15 +33,6 @@ namespace Org.OpenAPITools.Model
     [DataContract(Name = "Quadrilateral")]
     public partial class Quadrilateral : AbstractOpenAPISchema, IEquatable<Quadrilateral>, IValidatableObject
     {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="Quadrilateral" /> class.
-        /// </summary>
-        public Quadrilateral()
-        {
-            this.IsNullable = true;
-            this.SchemaType= "oneOf";
-        }
-
         /// <summary>
         /// Initializes a new instance of the <see cref="Quadrilateral" /> class
         /// with the <see cref="ComplexQuadrilateral" /> class
@@ -134,7 +125,7 @@ namespace Org.OpenAPITools.Model
         /// <returns>JSON string presentation of the object</returns>
         public override string ToJson()
         {
-            return JsonConvert.SerializeObject(this.ActualInstance, _serializerSettings);
+            return JsonConvert.SerializeObject(this.ActualInstance, Quadrilateral.SerializerSettings);
         }
 
         /// <summary>
@@ -144,19 +135,19 @@ namespace Org.OpenAPITools.Model
         /// <returns>An instance of Quadrilateral</returns>
         public static Quadrilateral FromJson(string jsonString)
         {
-            Quadrilateral newQuadrilateral = new Quadrilateral();
+            Quadrilateral newQuadrilateral = null;
 
             string discriminatorValue = JObject.Parse(jsonString)["quadrilateralType"].ToString();
             switch (discriminatorValue)
             {
                 case "ComplexQuadrilateral":
-                    newQuadrilateral.ActualInstance = JsonConvert.DeserializeObject<ComplexQuadrilateral>(jsonString, newQuadrilateral._serializerSettings);
+                    newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<ComplexQuadrilateral>(jsonString, Quadrilateral.SerializerSettings));
                     return newQuadrilateral;
                 case "SimpleQuadrilateral":
-                    newQuadrilateral.ActualInstance = JsonConvert.DeserializeObject<SimpleQuadrilateral>(jsonString, newQuadrilateral._serializerSettings);
+                    newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<SimpleQuadrilateral>(jsonString, Quadrilateral.SerializerSettings));
                     return newQuadrilateral;
                 default:
-                    System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `%s` for Quadrilateral. Possible values: ComplexQuadrilateral SimpleQuadrilateral", discriminatorValue));
+                    System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `{0}` for Quadrilateral. Possible values: ComplexQuadrilateral SimpleQuadrilateral", discriminatorValue));
                     break;
             }
 
@@ -165,26 +156,26 @@ namespace Org.OpenAPITools.Model
 
             try
             {
-                newQuadrilateral.ActualInstance = JsonConvert.DeserializeObject<ComplexQuadrilateral>(jsonString, newQuadrilateral._serializerSettings);
+                newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<ComplexQuadrilateral>(jsonString, Quadrilateral.SerializerSettings));
                 matchedTypes.Add("ComplexQuadrilateral");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into ComplexQuadrilateral: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into ComplexQuadrilateral: {1}", jsonString, exception.ToString()));
             }
 
             try
             {
-                newQuadrilateral.ActualInstance = JsonConvert.DeserializeObject<SimpleQuadrilateral>(jsonString, newQuadrilateral._serializerSettings);
+                newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<SimpleQuadrilateral>(jsonString, Quadrilateral.SerializerSettings));
                 matchedTypes.Add("SimpleQuadrilateral");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into SimpleQuadrilateral: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into SimpleQuadrilateral: {1}", jsonString, exception.ToString()));
             }
 
             if (match == 0)
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Shape.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Shape.cs
index 95ecc2dfd0f..43885c53f13 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Shape.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Shape.cs
@@ -33,15 +33,6 @@ namespace Org.OpenAPITools.Model
     [DataContract(Name = "Shape")]
     public partial class Shape : AbstractOpenAPISchema, IEquatable<Shape>, IValidatableObject
     {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="Shape" /> class.
-        /// </summary>
-        public Shape()
-        {
-            this.IsNullable = true;
-            this.SchemaType= "oneOf";
-        }
-
         /// <summary>
         /// Initializes a new instance of the <see cref="Shape" /> class
         /// with the <see cref="Quadrilateral" /> class
@@ -134,7 +125,7 @@ namespace Org.OpenAPITools.Model
         /// <returns>JSON string presentation of the object</returns>
         public override string ToJson()
         {
-            return JsonConvert.SerializeObject(this.ActualInstance, _serializerSettings);
+            return JsonConvert.SerializeObject(this.ActualInstance, Shape.SerializerSettings);
         }
 
         /// <summary>
@@ -144,19 +135,19 @@ namespace Org.OpenAPITools.Model
         /// <returns>An instance of Shape</returns>
         public static Shape FromJson(string jsonString)
         {
-            Shape newShape = new Shape();
+            Shape newShape = null;
 
             string discriminatorValue = JObject.Parse(jsonString)["shapeType"].ToString();
             switch (discriminatorValue)
             {
                 case "Quadrilateral":
-                    newShape.ActualInstance = JsonConvert.DeserializeObject<Quadrilateral>(jsonString, newShape._serializerSettings);
+                    newShape = new Shape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, Shape.SerializerSettings));
                     return newShape;
                 case "Triangle":
-                    newShape.ActualInstance = JsonConvert.DeserializeObject<Triangle>(jsonString, newShape._serializerSettings);
+                    newShape = new Shape(JsonConvert.DeserializeObject<Triangle>(jsonString, Shape.SerializerSettings));
                     return newShape;
                 default:
-                    System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `%s` for Shape. Possible values: Quadrilateral Triangle", discriminatorValue));
+                    System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `{0}` for Shape. Possible values: Quadrilateral Triangle", discriminatorValue));
                     break;
             }
 
@@ -165,26 +156,26 @@ namespace Org.OpenAPITools.Model
 
             try
             {
-                newShape.ActualInstance = JsonConvert.DeserializeObject<Quadrilateral>(jsonString, newShape._serializerSettings);
+                newShape = new Shape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, Shape.SerializerSettings));
                 matchedTypes.Add("Quadrilateral");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into Quadrilateral: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into Quadrilateral: {1}", jsonString, exception.ToString()));
             }
 
             try
             {
-                newShape.ActualInstance = JsonConvert.DeserializeObject<Triangle>(jsonString, newShape._serializerSettings);
+                newShape = new Shape(JsonConvert.DeserializeObject<Triangle>(jsonString, Shape.SerializerSettings));
                 matchedTypes.Add("Triangle");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into Triangle: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into Triangle: {1}", jsonString, exception.ToString()));
             }
 
             if (match == 0)
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/ShapeOrNull.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/ShapeOrNull.cs
index 838b4f885dc..80a9f0ecd7d 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/ShapeOrNull.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/ShapeOrNull.cs
@@ -134,7 +134,7 @@ namespace Org.OpenAPITools.Model
         /// <returns>JSON string presentation of the object</returns>
         public override string ToJson()
         {
-            return JsonConvert.SerializeObject(this.ActualInstance, _serializerSettings);
+            return JsonConvert.SerializeObject(this.ActualInstance, ShapeOrNull.SerializerSettings);
         }
 
         /// <summary>
@@ -144,19 +144,19 @@ namespace Org.OpenAPITools.Model
         /// <returns>An instance of ShapeOrNull</returns>
         public static ShapeOrNull FromJson(string jsonString)
         {
-            ShapeOrNull newShapeOrNull = new ShapeOrNull();
+            ShapeOrNull newShapeOrNull = null;
 
             string discriminatorValue = JObject.Parse(jsonString)["shapeType"].ToString();
             switch (discriminatorValue)
             {
                 case "Quadrilateral":
-                    newShapeOrNull.ActualInstance = JsonConvert.DeserializeObject<Quadrilateral>(jsonString, newShapeOrNull._serializerSettings);
+                    newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, ShapeOrNull.SerializerSettings));
                     return newShapeOrNull;
                 case "Triangle":
-                    newShapeOrNull.ActualInstance = JsonConvert.DeserializeObject<Triangle>(jsonString, newShapeOrNull._serializerSettings);
+                    newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Triangle>(jsonString, ShapeOrNull.SerializerSettings));
                     return newShapeOrNull;
                 default:
-                    System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `%s` for ShapeOrNull. Possible values: Quadrilateral Triangle", discriminatorValue));
+                    System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `{0}` for ShapeOrNull. Possible values: Quadrilateral Triangle", discriminatorValue));
                     break;
             }
 
@@ -165,26 +165,26 @@ namespace Org.OpenAPITools.Model
 
             try
             {
-                newShapeOrNull.ActualInstance = JsonConvert.DeserializeObject<Quadrilateral>(jsonString, newShapeOrNull._serializerSettings);
+                newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, ShapeOrNull.SerializerSettings));
                 matchedTypes.Add("Quadrilateral");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into Quadrilateral: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into Quadrilateral: {1}", jsonString, exception.ToString()));
             }
 
             try
             {
-                newShapeOrNull.ActualInstance = JsonConvert.DeserializeObject<Triangle>(jsonString, newShapeOrNull._serializerSettings);
+                newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Triangle>(jsonString, ShapeOrNull.SerializerSettings));
                 matchedTypes.Add("Triangle");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into Triangle: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into Triangle: {1}", jsonString, exception.ToString()));
             }
 
             if (match == 0)
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Triangle.cs b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Triangle.cs
index ba98a3b1d25..ae0d6fdbfbb 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Triangle.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClient/src/Org.OpenAPITools/Model/Triangle.cs
@@ -33,15 +33,6 @@ namespace Org.OpenAPITools.Model
     [DataContract(Name = "Triangle")]
     public partial class Triangle : AbstractOpenAPISchema, IEquatable<Triangle>, IValidatableObject
     {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="Triangle" /> class.
-        /// </summary>
-        public Triangle()
-        {
-            this.IsNullable = true;
-            this.SchemaType= "oneOf";
-        }
-
         /// <summary>
         /// Initializes a new instance of the <see cref="Triangle" /> class
         /// with the <see cref="EquilateralTriangle" /> class
@@ -160,7 +151,7 @@ namespace Org.OpenAPITools.Model
         /// <returns>JSON string presentation of the object</returns>
         public override string ToJson()
         {
-            return JsonConvert.SerializeObject(this.ActualInstance, _serializerSettings);
+            return JsonConvert.SerializeObject(this.ActualInstance, Triangle.SerializerSettings);
         }
 
         /// <summary>
@@ -170,22 +161,22 @@ namespace Org.OpenAPITools.Model
         /// <returns>An instance of Triangle</returns>
         public static Triangle FromJson(string jsonString)
         {
-            Triangle newTriangle = new Triangle();
+            Triangle newTriangle = null;
 
             string discriminatorValue = JObject.Parse(jsonString)["triangleType"].ToString();
             switch (discriminatorValue)
             {
                 case "EquilateralTriangle":
-                    newTriangle.ActualInstance = JsonConvert.DeserializeObject<EquilateralTriangle>(jsonString, newTriangle._serializerSettings);
+                    newTriangle = new Triangle(JsonConvert.DeserializeObject<EquilateralTriangle>(jsonString, Triangle.SerializerSettings));
                     return newTriangle;
                 case "IsoscelesTriangle":
-                    newTriangle.ActualInstance = JsonConvert.DeserializeObject<IsoscelesTriangle>(jsonString, newTriangle._serializerSettings);
+                    newTriangle = new Triangle(JsonConvert.DeserializeObject<IsoscelesTriangle>(jsonString, Triangle.SerializerSettings));
                     return newTriangle;
                 case "ScaleneTriangle":
-                    newTriangle.ActualInstance = JsonConvert.DeserializeObject<ScaleneTriangle>(jsonString, newTriangle._serializerSettings);
+                    newTriangle = new Triangle(JsonConvert.DeserializeObject<ScaleneTriangle>(jsonString, Triangle.SerializerSettings));
                     return newTriangle;
                 default:
-                    System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `%s` for Triangle. Possible values: EquilateralTriangle IsoscelesTriangle ScaleneTriangle", discriminatorValue));
+                    System.Diagnostics.Debug.WriteLine(String.Format("Failed to lookup discriminator value `{0}` for Triangle. Possible values: EquilateralTriangle IsoscelesTriangle ScaleneTriangle", discriminatorValue));
                     break;
             }
 
@@ -194,38 +185,38 @@ namespace Org.OpenAPITools.Model
 
             try
             {
-                newTriangle.ActualInstance = JsonConvert.DeserializeObject<EquilateralTriangle>(jsonString, newTriangle._serializerSettings);
+                newTriangle = new Triangle(JsonConvert.DeserializeObject<EquilateralTriangle>(jsonString, Triangle.SerializerSettings));
                 matchedTypes.Add("EquilateralTriangle");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into EquilateralTriangle: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into EquilateralTriangle: {1}", jsonString, exception.ToString()));
             }
 
             try
             {
-                newTriangle.ActualInstance = JsonConvert.DeserializeObject<IsoscelesTriangle>(jsonString, newTriangle._serializerSettings);
+                newTriangle = new Triangle(JsonConvert.DeserializeObject<IsoscelesTriangle>(jsonString, Triangle.SerializerSettings));
                 matchedTypes.Add("IsoscelesTriangle");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into IsoscelesTriangle: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into IsoscelesTriangle: {1}", jsonString, exception.ToString()));
             }
 
             try
             {
-                newTriangle.ActualInstance = JsonConvert.DeserializeObject<ScaleneTriangle>(jsonString, newTriangle._serializerSettings);
+                newTriangle = new Triangle(JsonConvert.DeserializeObject<ScaleneTriangle>(jsonString, Triangle.SerializerSettings));
                 matchedTypes.Add("ScaleneTriangle");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into ScaleneTriangle: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into ScaleneTriangle: {1}", jsonString, exception.ToString()));
             }
 
             if (match == 0)
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/AbstractOpenAPISchema.cs b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/AbstractOpenAPISchema.cs
index 2d3fda31aee..b37dea7796d 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/AbstractOpenAPISchema.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/AbstractOpenAPISchema.cs
@@ -22,7 +22,7 @@ namespace Org.OpenAPITools.Model
         /// <summary>
         ///  Custom JSON serializer
         /// </summary>
-        protected readonly JsonSerializerSettings _serializerSettings = new JsonSerializerSettings
+        static public readonly JsonSerializerSettings SerializerSettings = new JsonSerializerSettings
         {
             // OpenAPI generated types generally hide default constructors.
             ConstructorHandling = ConstructorHandling.AllowNonPublicDefaultConstructor,
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Fruit.cs b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Fruit.cs
index ee556c02c61..81874287d74 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Fruit.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Fruit.cs
@@ -32,15 +32,6 @@ namespace Org.OpenAPITools.Model
     [DataContract(Name = "fruit")]
     public partial class Fruit : AbstractOpenAPISchema, IEquatable<Fruit>, IValidatableObject
     {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="Fruit" /> class.
-        /// </summary>
-        public Fruit()
-        {
-            this.IsNullable = true;
-            this.SchemaType= "oneOf";
-        }
-
         /// <summary>
         /// Initializes a new instance of the <see cref="Fruit" /> class
         /// with the <see cref="Apple" /> class
@@ -133,7 +124,7 @@ namespace Org.OpenAPITools.Model
         /// <returns>JSON string presentation of the object</returns>
         public override string ToJson()
         {
-            return JsonConvert.SerializeObject(this.ActualInstance, _serializerSettings);
+            return JsonConvert.SerializeObject(this.ActualInstance, Fruit.SerializerSettings);
         }
 
         /// <summary>
@@ -143,32 +134,32 @@ namespace Org.OpenAPITools.Model
         /// <returns>An instance of Fruit</returns>
         public static Fruit FromJson(string jsonString)
         {
-            Fruit newFruit = new Fruit();
+            Fruit newFruit = null;
             int match = 0;
             List<string> matchedTypes = new List<string>();
 
             try
             {
-                newFruit.ActualInstance = JsonConvert.DeserializeObject<Apple>(jsonString, newFruit._serializerSettings);
+                newFruit = new Fruit(JsonConvert.DeserializeObject<Apple>(jsonString, Fruit.SerializerSettings));
                 matchedTypes.Add("Apple");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into Apple: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into Apple: {1}", jsonString, exception.ToString()));
             }
 
             try
             {
-                newFruit.ActualInstance = JsonConvert.DeserializeObject<Banana>(jsonString, newFruit._serializerSettings);
+                newFruit = new Fruit(JsonConvert.DeserializeObject<Banana>(jsonString, Fruit.SerializerSettings));
                 matchedTypes.Add("Banana");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into Banana: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into Banana: {1}", jsonString, exception.ToString()));
             }
 
             if (match == 0)
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/FruitReq.cs b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/FruitReq.cs
index 6e997adbd07..233db1a1fee 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/FruitReq.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/FruitReq.cs
@@ -133,7 +133,7 @@ namespace Org.OpenAPITools.Model
         /// <returns>JSON string presentation of the object</returns>
         public override string ToJson()
         {
-            return JsonConvert.SerializeObject(this.ActualInstance, _serializerSettings);
+            return JsonConvert.SerializeObject(this.ActualInstance, FruitReq.SerializerSettings);
         }
 
         /// <summary>
@@ -143,32 +143,32 @@ namespace Org.OpenAPITools.Model
         /// <returns>An instance of FruitReq</returns>
         public static FruitReq FromJson(string jsonString)
         {
-            FruitReq newFruitReq = new FruitReq();
+            FruitReq newFruitReq = null;
             int match = 0;
             List<string> matchedTypes = new List<string>();
 
             try
             {
-                newFruitReq.ActualInstance = JsonConvert.DeserializeObject<AppleReq>(jsonString, newFruitReq._serializerSettings);
+                newFruitReq = new FruitReq(JsonConvert.DeserializeObject<AppleReq>(jsonString, FruitReq.SerializerSettings));
                 matchedTypes.Add("AppleReq");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into AppleReq: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into AppleReq: {1}", jsonString, exception.ToString()));
             }
 
             try
             {
-                newFruitReq.ActualInstance = JsonConvert.DeserializeObject<BananaReq>(jsonString, newFruitReq._serializerSettings);
+                newFruitReq = new FruitReq(JsonConvert.DeserializeObject<BananaReq>(jsonString, FruitReq.SerializerSettings));
                 matchedTypes.Add("BananaReq");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into BananaReq: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into BananaReq: {1}", jsonString, exception.ToString()));
             }
 
             if (match == 0)
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Mammal.cs b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Mammal.cs
index ec33598d3b5..ddfd4a8d0e5 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Mammal.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Mammal.cs
@@ -33,15 +33,6 @@ namespace Org.OpenAPITools.Model
     [DataContract(Name = "mammal")]
     public partial class Mammal : AbstractOpenAPISchema, IEquatable<Mammal>, IValidatableObject
     {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="Mammal" /> class.
-        /// </summary>
-        public Mammal()
-        {
-            this.IsNullable = true;
-            this.SchemaType= "oneOf";
-        }
-
         /// <summary>
         /// Initializes a new instance of the <see cref="Mammal" /> class
         /// with the <see cref="Pig" /> class
@@ -160,7 +151,7 @@ namespace Org.OpenAPITools.Model
         /// <returns>JSON string presentation of the object</returns>
         public override string ToJson()
         {
-            return JsonConvert.SerializeObject(this.ActualInstance, _serializerSettings);
+            return JsonConvert.SerializeObject(this.ActualInstance, Mammal.SerializerSettings);
         }
 
         /// <summary>
@@ -170,44 +161,44 @@ namespace Org.OpenAPITools.Model
         /// <returns>An instance of Mammal</returns>
         public static Mammal FromJson(string jsonString)
         {
-            Mammal newMammal = new Mammal();
+            Mammal newMammal = null;
             int match = 0;
             List<string> matchedTypes = new List<string>();
 
             try
             {
-                newMammal.ActualInstance = JsonConvert.DeserializeObject<Pig>(jsonString, newMammal._serializerSettings);
+                newMammal = new Mammal(JsonConvert.DeserializeObject<Pig>(jsonString, Mammal.SerializerSettings));
                 matchedTypes.Add("Pig");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into Pig: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into Pig: {1}", jsonString, exception.ToString()));
             }
 
             try
             {
-                newMammal.ActualInstance = JsonConvert.DeserializeObject<Whale>(jsonString, newMammal._serializerSettings);
+                newMammal = new Mammal(JsonConvert.DeserializeObject<Whale>(jsonString, Mammal.SerializerSettings));
                 matchedTypes.Add("Whale");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into Whale: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into Whale: {1}", jsonString, exception.ToString()));
             }
 
             try
             {
-                newMammal.ActualInstance = JsonConvert.DeserializeObject<Zebra>(jsonString, newMammal._serializerSettings);
+                newMammal = new Mammal(JsonConvert.DeserializeObject<Zebra>(jsonString, Mammal.SerializerSettings));
                 matchedTypes.Add("Zebra");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into Zebra: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into Zebra: {1}", jsonString, exception.ToString()));
             }
 
             if (match == 0)
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/NullableShape.cs b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/NullableShape.cs
index c5eac289776..473aec6f747 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/NullableShape.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/NullableShape.cs
@@ -134,7 +134,7 @@ namespace Org.OpenAPITools.Model
         /// <returns>JSON string presentation of the object</returns>
         public override string ToJson()
         {
-            return JsonConvert.SerializeObject(this.ActualInstance, _serializerSettings);
+            return JsonConvert.SerializeObject(this.ActualInstance, NullableShape.SerializerSettings);
         }
 
         /// <summary>
@@ -144,32 +144,32 @@ namespace Org.OpenAPITools.Model
         /// <returns>An instance of NullableShape</returns>
         public static NullableShape FromJson(string jsonString)
         {
-            NullableShape newNullableShape = new NullableShape();
+            NullableShape newNullableShape = null;
             int match = 0;
             List<string> matchedTypes = new List<string>();
 
             try
             {
-                newNullableShape.ActualInstance = JsonConvert.DeserializeObject<Quadrilateral>(jsonString, newNullableShape._serializerSettings);
+                newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, NullableShape.SerializerSettings));
                 matchedTypes.Add("Quadrilateral");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into Quadrilateral: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into Quadrilateral: {1}", jsonString, exception.ToString()));
             }
 
             try
             {
-                newNullableShape.ActualInstance = JsonConvert.DeserializeObject<Triangle>(jsonString, newNullableShape._serializerSettings);
+                newNullableShape = new NullableShape(JsonConvert.DeserializeObject<Triangle>(jsonString, NullableShape.SerializerSettings));
                 matchedTypes.Add("Triangle");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into Triangle: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into Triangle: {1}", jsonString, exception.ToString()));
             }
 
             if (match == 0)
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Pig.cs b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Pig.cs
index d61ca3d16dc..dbb507b642f 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Pig.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Pig.cs
@@ -33,15 +33,6 @@ namespace Org.OpenAPITools.Model
     [DataContract(Name = "Pig")]
     public partial class Pig : AbstractOpenAPISchema, IEquatable<Pig>, IValidatableObject
     {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="Pig" /> class.
-        /// </summary>
-        public Pig()
-        {
-            this.IsNullable = true;
-            this.SchemaType= "oneOf";
-        }
-
         /// <summary>
         /// Initializes a new instance of the <see cref="Pig" /> class
         /// with the <see cref="BasquePig" /> class
@@ -134,7 +125,7 @@ namespace Org.OpenAPITools.Model
         /// <returns>JSON string presentation of the object</returns>
         public override string ToJson()
         {
-            return JsonConvert.SerializeObject(this.ActualInstance, _serializerSettings);
+            return JsonConvert.SerializeObject(this.ActualInstance, Pig.SerializerSettings);
         }
 
         /// <summary>
@@ -144,32 +135,32 @@ namespace Org.OpenAPITools.Model
         /// <returns>An instance of Pig</returns>
         public static Pig FromJson(string jsonString)
         {
-            Pig newPig = new Pig();
+            Pig newPig = null;
             int match = 0;
             List<string> matchedTypes = new List<string>();
 
             try
             {
-                newPig.ActualInstance = JsonConvert.DeserializeObject<BasquePig>(jsonString, newPig._serializerSettings);
+                newPig = new Pig(JsonConvert.DeserializeObject<BasquePig>(jsonString, Pig.SerializerSettings));
                 matchedTypes.Add("BasquePig");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into BasquePig: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into BasquePig: {1}", jsonString, exception.ToString()));
             }
 
             try
             {
-                newPig.ActualInstance = JsonConvert.DeserializeObject<DanishPig>(jsonString, newPig._serializerSettings);
+                newPig = new Pig(JsonConvert.DeserializeObject<DanishPig>(jsonString, Pig.SerializerSettings));
                 matchedTypes.Add("DanishPig");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into DanishPig: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into DanishPig: {1}", jsonString, exception.ToString()));
             }
 
             if (match == 0)
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Quadrilateral.cs b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Quadrilateral.cs
index 69e004d99b1..dd7b5258898 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Quadrilateral.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Quadrilateral.cs
@@ -33,15 +33,6 @@ namespace Org.OpenAPITools.Model
     [DataContract(Name = "Quadrilateral")]
     public partial class Quadrilateral : AbstractOpenAPISchema, IEquatable<Quadrilateral>, IValidatableObject
     {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="Quadrilateral" /> class.
-        /// </summary>
-        public Quadrilateral()
-        {
-            this.IsNullable = true;
-            this.SchemaType= "oneOf";
-        }
-
         /// <summary>
         /// Initializes a new instance of the <see cref="Quadrilateral" /> class
         /// with the <see cref="ComplexQuadrilateral" /> class
@@ -134,7 +125,7 @@ namespace Org.OpenAPITools.Model
         /// <returns>JSON string presentation of the object</returns>
         public override string ToJson()
         {
-            return JsonConvert.SerializeObject(this.ActualInstance, _serializerSettings);
+            return JsonConvert.SerializeObject(this.ActualInstance, Quadrilateral.SerializerSettings);
         }
 
         /// <summary>
@@ -144,32 +135,32 @@ namespace Org.OpenAPITools.Model
         /// <returns>An instance of Quadrilateral</returns>
         public static Quadrilateral FromJson(string jsonString)
         {
-            Quadrilateral newQuadrilateral = new Quadrilateral();
+            Quadrilateral newQuadrilateral = null;
             int match = 0;
             List<string> matchedTypes = new List<string>();
 
             try
             {
-                newQuadrilateral.ActualInstance = JsonConvert.DeserializeObject<ComplexQuadrilateral>(jsonString, newQuadrilateral._serializerSettings);
+                newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<ComplexQuadrilateral>(jsonString, Quadrilateral.SerializerSettings));
                 matchedTypes.Add("ComplexQuadrilateral");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into ComplexQuadrilateral: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into ComplexQuadrilateral: {1}", jsonString, exception.ToString()));
             }
 
             try
             {
-                newQuadrilateral.ActualInstance = JsonConvert.DeserializeObject<SimpleQuadrilateral>(jsonString, newQuadrilateral._serializerSettings);
+                newQuadrilateral = new Quadrilateral(JsonConvert.DeserializeObject<SimpleQuadrilateral>(jsonString, Quadrilateral.SerializerSettings));
                 matchedTypes.Add("SimpleQuadrilateral");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into SimpleQuadrilateral: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into SimpleQuadrilateral: {1}", jsonString, exception.ToString()));
             }
 
             if (match == 0)
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Shape.cs b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Shape.cs
index f9fa8ce1eb3..b5383beedf0 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Shape.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Shape.cs
@@ -33,15 +33,6 @@ namespace Org.OpenAPITools.Model
     [DataContract(Name = "Shape")]
     public partial class Shape : AbstractOpenAPISchema, IEquatable<Shape>, IValidatableObject
     {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="Shape" /> class.
-        /// </summary>
-        public Shape()
-        {
-            this.IsNullable = true;
-            this.SchemaType= "oneOf";
-        }
-
         /// <summary>
         /// Initializes a new instance of the <see cref="Shape" /> class
         /// with the <see cref="Quadrilateral" /> class
@@ -134,7 +125,7 @@ namespace Org.OpenAPITools.Model
         /// <returns>JSON string presentation of the object</returns>
         public override string ToJson()
         {
-            return JsonConvert.SerializeObject(this.ActualInstance, _serializerSettings);
+            return JsonConvert.SerializeObject(this.ActualInstance, Shape.SerializerSettings);
         }
 
         /// <summary>
@@ -144,32 +135,32 @@ namespace Org.OpenAPITools.Model
         /// <returns>An instance of Shape</returns>
         public static Shape FromJson(string jsonString)
         {
-            Shape newShape = new Shape();
+            Shape newShape = null;
             int match = 0;
             List<string> matchedTypes = new List<string>();
 
             try
             {
-                newShape.ActualInstance = JsonConvert.DeserializeObject<Quadrilateral>(jsonString, newShape._serializerSettings);
+                newShape = new Shape(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, Shape.SerializerSettings));
                 matchedTypes.Add("Quadrilateral");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into Quadrilateral: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into Quadrilateral: {1}", jsonString, exception.ToString()));
             }
 
             try
             {
-                newShape.ActualInstance = JsonConvert.DeserializeObject<Triangle>(jsonString, newShape._serializerSettings);
+                newShape = new Shape(JsonConvert.DeserializeObject<Triangle>(jsonString, Shape.SerializerSettings));
                 matchedTypes.Add("Triangle");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into Triangle: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into Triangle: {1}", jsonString, exception.ToString()));
             }
 
             if (match == 0)
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/ShapeOrNull.cs b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/ShapeOrNull.cs
index 3ea7b875fbb..ca90b2285ae 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/ShapeOrNull.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/ShapeOrNull.cs
@@ -134,7 +134,7 @@ namespace Org.OpenAPITools.Model
         /// <returns>JSON string presentation of the object</returns>
         public override string ToJson()
         {
-            return JsonConvert.SerializeObject(this.ActualInstance, _serializerSettings);
+            return JsonConvert.SerializeObject(this.ActualInstance, ShapeOrNull.SerializerSettings);
         }
 
         /// <summary>
@@ -144,32 +144,32 @@ namespace Org.OpenAPITools.Model
         /// <returns>An instance of ShapeOrNull</returns>
         public static ShapeOrNull FromJson(string jsonString)
         {
-            ShapeOrNull newShapeOrNull = new ShapeOrNull();
+            ShapeOrNull newShapeOrNull = null;
             int match = 0;
             List<string> matchedTypes = new List<string>();
 
             try
             {
-                newShapeOrNull.ActualInstance = JsonConvert.DeserializeObject<Quadrilateral>(jsonString, newShapeOrNull._serializerSettings);
+                newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Quadrilateral>(jsonString, ShapeOrNull.SerializerSettings));
                 matchedTypes.Add("Quadrilateral");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into Quadrilateral: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into Quadrilateral: {1}", jsonString, exception.ToString()));
             }
 
             try
             {
-                newShapeOrNull.ActualInstance = JsonConvert.DeserializeObject<Triangle>(jsonString, newShapeOrNull._serializerSettings);
+                newShapeOrNull = new ShapeOrNull(JsonConvert.DeserializeObject<Triangle>(jsonString, ShapeOrNull.SerializerSettings));
                 matchedTypes.Add("Triangle");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into Triangle: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into Triangle: {1}", jsonString, exception.ToString()));
             }
 
             if (match == 0)
diff --git a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Triangle.cs b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Triangle.cs
index 8dc4576c57c..26dce011fd9 100644
--- a/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Triangle.cs
+++ b/samples/client/petstore/csharp-netcore/OpenAPIClientCore/src/Org.OpenAPITools/Model/Triangle.cs
@@ -33,15 +33,6 @@ namespace Org.OpenAPITools.Model
     [DataContract(Name = "Triangle")]
     public partial class Triangle : AbstractOpenAPISchema, IEquatable<Triangle>, IValidatableObject
     {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="Triangle" /> class.
-        /// </summary>
-        public Triangle()
-        {
-            this.IsNullable = true;
-            this.SchemaType= "oneOf";
-        }
-
         /// <summary>
         /// Initializes a new instance of the <see cref="Triangle" /> class
         /// with the <see cref="EquilateralTriangle" /> class
@@ -160,7 +151,7 @@ namespace Org.OpenAPITools.Model
         /// <returns>JSON string presentation of the object</returns>
         public override string ToJson()
         {
-            return JsonConvert.SerializeObject(this.ActualInstance, _serializerSettings);
+            return JsonConvert.SerializeObject(this.ActualInstance, Triangle.SerializerSettings);
         }
 
         /// <summary>
@@ -170,44 +161,44 @@ namespace Org.OpenAPITools.Model
         /// <returns>An instance of Triangle</returns>
         public static Triangle FromJson(string jsonString)
         {
-            Triangle newTriangle = new Triangle();
+            Triangle newTriangle = null;
             int match = 0;
             List<string> matchedTypes = new List<string>();
 
             try
             {
-                newTriangle.ActualInstance = JsonConvert.DeserializeObject<EquilateralTriangle>(jsonString, newTriangle._serializerSettings);
+                newTriangle = new Triangle(JsonConvert.DeserializeObject<EquilateralTriangle>(jsonString, Triangle.SerializerSettings));
                 matchedTypes.Add("EquilateralTriangle");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into EquilateralTriangle: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into EquilateralTriangle: {1}", jsonString, exception.ToString()));
             }
 
             try
             {
-                newTriangle.ActualInstance = JsonConvert.DeserializeObject<IsoscelesTriangle>(jsonString, newTriangle._serializerSettings);
+                newTriangle = new Triangle(JsonConvert.DeserializeObject<IsoscelesTriangle>(jsonString, Triangle.SerializerSettings));
                 matchedTypes.Add("IsoscelesTriangle");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into IsoscelesTriangle: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into IsoscelesTriangle: {1}", jsonString, exception.ToString()));
             }
 
             try
             {
-                newTriangle.ActualInstance = JsonConvert.DeserializeObject<ScaleneTriangle>(jsonString, newTriangle._serializerSettings);
+                newTriangle = new Triangle(JsonConvert.DeserializeObject<ScaleneTriangle>(jsonString, Triangle.SerializerSettings));
                 matchedTypes.Add("ScaleneTriangle");
                 match++;
             }
             catch (Exception exception)
             {
                 // deserialization failed, try the next one
-                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `%s` into ScaleneTriangle: %s", jsonString, exception.ToString()));
+                System.Diagnostics.Debug.WriteLine(String.Format("Failed to deserialize `{0}` into ScaleneTriangle: {1}", jsonString, exception.ToString()));
             }
 
             if (match == 0)