diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/JSON.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/JSON.mustache
index 3d3339c5d6b..bcc075ac9fc 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/JSON.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/JSON.mustache
@@ -84,10 +84,10 @@ public class JSON implements ContextResolver<ObjectMapper> {
    * @param node The input data.
    * @param modelClass The class that contains the discriminator mappings.
    */
-  public static Class getClassForElement(JsonNode node, Class modelClass) {
+  public static Class<?> getClassForElement(JsonNode node, Class<?> modelClass) {
     ClassDiscriminatorMapping cdm = modelDiscriminators.get(modelClass);
     if (cdm != null) {
-      return cdm.getClassForElement(node, new HashSet<Class>());
+      return cdm.getClassForElement(node, new HashSet<Class<?>>());
     }
     return null;
   }
@@ -97,17 +97,17 @@ public class JSON implements ContextResolver<ObjectMapper> {
    */
   private static class ClassDiscriminatorMapping {
     // The model class name.
-    Class modelClass;
+    Class<?> modelClass;
     // The name of the discriminator property.
     String discriminatorName;
     // The discriminator mappings for a model class.
-    Map<String, Class> discriminatorMappings;
+    Map<String, Class<?>> discriminatorMappings;
 
     // Constructs a new class discriminator.
-    ClassDiscriminatorMapping(Class cls, String propertyName, Map<String, Class> mappings) {
+    ClassDiscriminatorMapping(Class<?> cls, String propertyName, Map<String, Class<?>> mappings) {
       modelClass = cls;
       discriminatorName = propertyName;
-      discriminatorMappings = new HashMap<String, Class>();
+      discriminatorMappings = new HashMap<String, Class<?>>();
       if (mappings != null) {
         discriminatorMappings.putAll(mappings);
       }
@@ -143,7 +143,7 @@ public class JSON implements ContextResolver<ObjectMapper> {
      * @param node The input data.
      * @param visitedClasses The set of classes that have already been visited.
      */
-    Class getClassForElement(JsonNode node, Set<Class> visitedClasses) {
+    Class<?> getClassForElement(JsonNode node, Set<Class<?>> visitedClasses) {
       if (visitedClasses.contains(modelClass)) {
         // Class has already been visited.
         return null;
@@ -153,11 +153,11 @@ public class JSON implements ContextResolver<ObjectMapper> {
       if (discrValue == null) {
         return null;
       }
-      Class cls = discriminatorMappings.get(discrValue);
+      Class<?> cls = discriminatorMappings.get(discrValue);
       // It may not be sufficient to return this cls directly because that target class
       // may itself be a composed schema, possibly with its own discriminator.
       visitedClasses.add(modelClass);
-      for (Class childClass : discriminatorMappings.values()) {
+      for (Class<?> childClass : discriminatorMappings.values()) {
         ClassDiscriminatorMapping childCdm = modelDiscriminators.get(childClass);
         if (childCdm == null) {
           continue;
@@ -170,7 +170,7 @@ public class JSON implements ContextResolver<ObjectMapper> {
         }
         if (childCdm != null) {
           // Recursively traverse the discriminator mappings.
-          Class childDiscr = childCdm.getClassForElement(node, visitedClasses);
+          Class<?> childDiscr = childCdm.getClassForElement(node, visitedClasses);
           if (childDiscr != null) {
             return childDiscr;
           }
@@ -189,7 +189,7 @@ public class JSON implements ContextResolver<ObjectMapper> {
    * @param modelClass A OpenAPI model class.
    * @param inst The instance object.
    */
-  public static boolean isInstanceOf(Class modelClass, Object inst, Set<Class> visitedClasses) {
+  public static boolean isInstanceOf(Class<?> modelClass, Object inst, Set<Class<?>> visitedClasses) {
     if (modelClass.isInstance(inst)) {
       // This handles the 'allOf' use case with single parent inheritance.
       return true;
@@ -216,12 +216,12 @@ public class JSON implements ContextResolver<ObjectMapper> {
   /**
    * A map of discriminators for all model classes.
    */
-  private static Map<Class, ClassDiscriminatorMapping> modelDiscriminators = new HashMap<Class, ClassDiscriminatorMapping>();
+  private static Map<Class<?>, ClassDiscriminatorMapping> modelDiscriminators = new HashMap<Class<?>, ClassDiscriminatorMapping>();
 
   /**
    * A map of oneOf/anyOf descendants for each model class.
    */
-  private static Map<Class, Map<String, GenericType>> modelDescendants = new HashMap<Class, Map<String, GenericType>>();
+  private static Map<Class<?>, Map<String, GenericType>> modelDescendants = new HashMap<Class<?>, Map<String, GenericType>>();
 
   /**
     * Register a model class discriminator.
@@ -230,7 +230,7 @@ public class JSON implements ContextResolver<ObjectMapper> {
     * @param discriminatorPropertyName the name of the discriminator property
     * @param mappings a map with the discriminator mappings.
     */
-  public static void registerDiscriminator(Class modelClass, String discriminatorPropertyName, Map<String, Class> mappings) {
+  public static void registerDiscriminator(Class<?> modelClass, String discriminatorPropertyName, Map<String, Class<?>> mappings) {
     ClassDiscriminatorMapping m = new ClassDiscriminatorMapping(modelClass, discriminatorPropertyName, mappings);
     modelDiscriminators.put(modelClass, m);
   }
@@ -241,7 +241,7 @@ public class JSON implements ContextResolver<ObjectMapper> {
     * @param modelClass the model class
     * @param descendants a map of oneOf/anyOf descendants.
     */
-  public static void registerDescendants(Class modelClass, Map<String, GenericType> descendants) {
+  public static void registerDescendants(Class<?> modelClass, Map<String, GenericType> descendants) {
     modelDescendants.put(modelClass, descendants);
   }
 
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/anyof_model.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/anyof_model.mustache
index 0ca3162c5ec..ef91fb3204b 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/anyof_model.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/anyof_model.mustache
@@ -57,7 +57,7 @@ public class {{classname}} extends AbstractOpenApiSchema{{#vendorExtensions.x-im
 
             Object deserialized = null;
             {{#discriminator}}
-            Class cls = JSON.getClassForElement(tree, {{classname}}.class);
+            Class<?> cls = JSON.getClassForElement(tree, {{classname}}.class);
             if (cls != null) {
                 // When the OAS schema includes a discriminator, use the discriminator value to
                 // discriminate the anyOf schemas.
@@ -115,7 +115,7 @@ public class {{classname}} extends AbstractOpenApiSchema{{#vendorExtensions.x-im
             return null;
         {{/isNullable}}
         {{^isNullable}}
-            throw new JsonMappingException("{{classname}} cannot be null");
+            throw new JsonMappingException(ctxt.getParser(), "{{classname}} cannot be null");
         {{/isNullable}}
         }
     }
@@ -153,7 +153,7 @@ public class {{classname}} extends AbstractOpenApiSchema{{#vendorExtensions.x-im
         JSON.registerDescendants({{classname}}.class, Collections.unmodifiableMap(schemas));
         {{#discriminator}}
         // Initialize and register the discriminator mappings.
-        Map<String, Class> mappings = new HashMap<String, Class>();
+        Map<String, Class<?>> mappings = new HashMap<String, Class<?>>();
         {{#mappedModels}}
         mappings.put("{{mappingName}}", {{modelName}}.class);
         {{/mappedModels}}
@@ -177,7 +177,7 @@ public class {{classname}} extends AbstractOpenApiSchema{{#vendorExtensions.x-im
 
         {{/isNullable}}
         {{#anyOf}}
-        if (JSON.isInstanceOf({{{.}}}.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf({{{.}}}.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/oneof_model.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/oneof_model.mustache
index 4ff6bb6d079..2289c28360a 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/oneof_model.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/oneof_model.mustache
@@ -128,7 +128,7 @@ public class {{classname}} extends AbstractOpenApiSchema{{#vendorExtensions.x-im
             return null;
         {{/isNullable}}
         {{^isNullable}}
-            throw new JsonMappingException("{{classname}} cannot be null");
+            throw new JsonMappingException(ctxt.getParser(), "{{classname}} cannot be null");
         {{/isNullable}}
         }
     }
@@ -166,7 +166,7 @@ public class {{classname}} extends AbstractOpenApiSchema{{#vendorExtensions.x-im
         JSON.registerDescendants({{classname}}.class, Collections.unmodifiableMap(schemas));
         {{#discriminator}}
         // Initialize and register the discriminator mappings.
-        Map<String, Class> mappings = new HashMap<String, Class>();
+        Map<String, Class<?>> mappings = new HashMap<String, Class<?>>();
         {{#mappedModels}}
         mappings.put("{{mappingName}}", {{modelName}}.class);
         {{/mappedModels}}
@@ -197,7 +197,7 @@ public class {{classname}} extends AbstractOpenApiSchema{{#vendorExtensions.x-im
 
         {{/isNullable}}
         {{#oneOf}}
-        if (JSON.isInstanceOf({{{.}}}.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf({{{.}}}.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/pojo.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/pojo.mustache
index 19e82e3dfa6..af6f2491cbd 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/pojo.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/pojo.mustache
@@ -377,7 +377,7 @@ public class {{classname}} {{#parent}}extends {{{parent}}} {{/parent}}{{#vendorE
 {{#discriminator}}
 static {
   // Initialize and register the discriminator mappings.
-  Map<String, Class> mappings = new HashMap<String, Class>();
+  Map<String, Class<?>> mappings = new HashMap<String, Class<?>>();
   {{#mappedModels}}
   mappings.put("{{mappingName}}", {{modelName}}.class);
   {{/mappedModels}}
diff --git a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/JSON.java b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/JSON.java
index be73bb23def..8f10d619a8f 100644
--- a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/JSON.java
+++ b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/JSON.java
@@ -59,10 +59,10 @@ public class JSON implements ContextResolver<ObjectMapper> {
    * @param node The input data.
    * @param modelClass The class that contains the discriminator mappings.
    */
-  public static Class getClassForElement(JsonNode node, Class modelClass) {
+  public static Class<?> getClassForElement(JsonNode node, Class<?> modelClass) {
     ClassDiscriminatorMapping cdm = modelDiscriminators.get(modelClass);
     if (cdm != null) {
-      return cdm.getClassForElement(node, new HashSet<Class>());
+      return cdm.getClassForElement(node, new HashSet<Class<?>>());
     }
     return null;
   }
@@ -72,17 +72,17 @@ public class JSON implements ContextResolver<ObjectMapper> {
    */
   private static class ClassDiscriminatorMapping {
     // The model class name.
-    Class modelClass;
+    Class<?> modelClass;
     // The name of the discriminator property.
     String discriminatorName;
     // The discriminator mappings for a model class.
-    Map<String, Class> discriminatorMappings;
+    Map<String, Class<?>> discriminatorMappings;
 
     // Constructs a new class discriminator.
-    ClassDiscriminatorMapping(Class cls, String propertyName, Map<String, Class> mappings) {
+    ClassDiscriminatorMapping(Class<?> cls, String propertyName, Map<String, Class<?>> mappings) {
       modelClass = cls;
       discriminatorName = propertyName;
-      discriminatorMappings = new HashMap<String, Class>();
+      discriminatorMappings = new HashMap<String, Class<?>>();
       if (mappings != null) {
         discriminatorMappings.putAll(mappings);
       }
@@ -118,7 +118,7 @@ public class JSON implements ContextResolver<ObjectMapper> {
      * @param node The input data.
      * @param visitedClasses The set of classes that have already been visited.
      */
-    Class getClassForElement(JsonNode node, Set<Class> visitedClasses) {
+    Class<?> getClassForElement(JsonNode node, Set<Class<?>> visitedClasses) {
       if (visitedClasses.contains(modelClass)) {
         // Class has already been visited.
         return null;
@@ -128,11 +128,11 @@ public class JSON implements ContextResolver<ObjectMapper> {
       if (discrValue == null) {
         return null;
       }
-      Class cls = discriminatorMappings.get(discrValue);
+      Class<?> cls = discriminatorMappings.get(discrValue);
       // It may not be sufficient to return this cls directly because that target class
       // may itself be a composed schema, possibly with its own discriminator.
       visitedClasses.add(modelClass);
-      for (Class childClass : discriminatorMappings.values()) {
+      for (Class<?> childClass : discriminatorMappings.values()) {
         ClassDiscriminatorMapping childCdm = modelDiscriminators.get(childClass);
         if (childCdm == null) {
           continue;
@@ -145,7 +145,7 @@ public class JSON implements ContextResolver<ObjectMapper> {
         }
         if (childCdm != null) {
           // Recursively traverse the discriminator mappings.
-          Class childDiscr = childCdm.getClassForElement(node, visitedClasses);
+          Class<?> childDiscr = childCdm.getClassForElement(node, visitedClasses);
           if (childDiscr != null) {
             return childDiscr;
           }
@@ -164,7 +164,7 @@ public class JSON implements ContextResolver<ObjectMapper> {
    * @param modelClass A OpenAPI model class.
    * @param inst The instance object.
    */
-  public static boolean isInstanceOf(Class modelClass, Object inst, Set<Class> visitedClasses) {
+  public static boolean isInstanceOf(Class<?> modelClass, Object inst, Set<Class<?>> visitedClasses) {
     if (modelClass.isInstance(inst)) {
       // This handles the 'allOf' use case with single parent inheritance.
       return true;
@@ -191,12 +191,12 @@ public class JSON implements ContextResolver<ObjectMapper> {
   /**
    * A map of discriminators for all model classes.
    */
-  private static Map<Class, ClassDiscriminatorMapping> modelDiscriminators = new HashMap<Class, ClassDiscriminatorMapping>();
+  private static Map<Class<?>, ClassDiscriminatorMapping> modelDiscriminators = new HashMap<Class<?>, ClassDiscriminatorMapping>();
 
   /**
    * A map of oneOf/anyOf descendants for each model class.
    */
-  private static Map<Class, Map<String, GenericType>> modelDescendants = new HashMap<Class, Map<String, GenericType>>();
+  private static Map<Class<?>, Map<String, GenericType>> modelDescendants = new HashMap<Class<?>, Map<String, GenericType>>();
 
   /**
     * Register a model class discriminator.
@@ -205,7 +205,7 @@ public class JSON implements ContextResolver<ObjectMapper> {
     * @param discriminatorPropertyName the name of the discriminator property
     * @param mappings a map with the discriminator mappings.
     */
-  public static void registerDiscriminator(Class modelClass, String discriminatorPropertyName, Map<String, Class> mappings) {
+  public static void registerDiscriminator(Class<?> modelClass, String discriminatorPropertyName, Map<String, Class<?>> mappings) {
     ClassDiscriminatorMapping m = new ClassDiscriminatorMapping(modelClass, discriminatorPropertyName, mappings);
     modelDiscriminators.put(modelClass, m);
   }
@@ -216,7 +216,7 @@ public class JSON implements ContextResolver<ObjectMapper> {
     * @param modelClass the model class
     * @param descendants a map of oneOf/anyOf descendants.
     */
-  public static void registerDescendants(Class modelClass, Map<String, GenericType> descendants) {
+  public static void registerDescendants(Class<?> modelClass, Map<String, GenericType> descendants) {
     modelDescendants.put(modelClass, descendants);
   }
 
diff --git a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Animal.java b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Animal.java
index 922b3987935..80fe6a16daa 100644
--- a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Animal.java
+++ b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Animal.java
@@ -144,7 +144,7 @@ public class Animal {
 
 static {
   // Initialize and register the discriminator mappings.
-  Map<String, Class> mappings = new HashMap<String, Class>();
+  Map<String, Class<?>> mappings = new HashMap<String, Class<?>>();
   mappings.put("BigCat", BigCat.class);
   mappings.put("Cat", Cat.class);
   mappings.put("Dog", Dog.class);
diff --git a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/BigCat.java b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/BigCat.java
index 3a6bebf323e..1a9e9a2a782 100644
--- a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/BigCat.java
+++ b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/BigCat.java
@@ -152,7 +152,7 @@ public class BigCat extends Cat {
 
 static {
   // Initialize and register the discriminator mappings.
-  Map<String, Class> mappings = new HashMap<String, Class>();
+  Map<String, Class<?>> mappings = new HashMap<String, Class<?>>();
   mappings.put("BigCat", BigCat.class);
   JSON.registerDiscriminator(BigCat.class, "className", mappings);
 }
diff --git a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Cat.java b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Cat.java
index acfeb71c955..59a01eeb7b9 100644
--- a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Cat.java
+++ b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Cat.java
@@ -115,7 +115,7 @@ public class Cat extends Animal {
 
 static {
   // Initialize and register the discriminator mappings.
-  Map<String, Class> mappings = new HashMap<String, Class>();
+  Map<String, Class<?>> mappings = new HashMap<String, Class<?>>();
   mappings.put("BigCat", BigCat.class);
   mappings.put("Cat", Cat.class);
   JSON.registerDiscriminator(Cat.class, "className", mappings);
diff --git a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Dog.java b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Dog.java
index 6166619f5f9..4b78ba6694b 100644
--- a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Dog.java
+++ b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Dog.java
@@ -113,7 +113,7 @@ public class Dog extends Animal {
 
 static {
   // Initialize and register the discriminator mappings.
-  Map<String, Class> mappings = new HashMap<String, Class>();
+  Map<String, Class<?>> mappings = new HashMap<String, Class<?>>();
   mappings.put("Dog", Dog.class);
   JSON.registerDiscriminator(Dog.class, "className", mappings);
 }
diff --git a/samples/client/petstore/java/jersey2-java8/src/test/java/org/openapitools/client/JSONTest.java b/samples/client/petstore/java/jersey2-java8/src/test/java/org/openapitools/client/JSONTest.java
index 7fb307a3df8..dda1ef9c1ef 100644
--- a/samples/client/petstore/java/jersey2-java8/src/test/java/org/openapitools/client/JSONTest.java
+++ b/samples/client/petstore/java/jersey2-java8/src/test/java/org/openapitools/client/JSONTest.java
@@ -3,7 +3,9 @@ package org.openapitools.client;
 import org.openapitools.client.model.Order;
 
 import java.lang.Exception;
-
+import java.util.Date;
+import java.util.TimeZone;
+import java.text.SimpleDateFormat;
 import java.time.OffsetDateTime;
 import java.time.ZoneId;
 import java.time.format.DateTimeFormatter;
@@ -32,6 +34,33 @@ public class JSONTest {
         assertEquals(dateStr, dateFormat.format(o.getShipDate()));
     }
 
+    @Test
+    public void testRFC3339DateFormatDate() throws Exception {
+        {
+            String dateStr = "2011-01-18 00:00:00.0Z";
+            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.S'Z'");
+            sdf.setTimeZone(TimeZone.getTimeZone("GMT"));
+            Date date = sdf.parse(dateStr);
+            
+            RFC3339DateFormat df = new RFC3339DateFormat();
+            StringBuffer sb = new StringBuffer();
+            String s = df.format(date);
+            System.out.println("DATE: " + s);
+            assertEquals("2011-01-18T00:00:00.000Z", s);
+        }
+        {
+            String dateStr = "2011-01-18 00:00:00.0";
+            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.S");
+            sdf.setTimeZone(TimeZone.getTimeZone("America/Los_Angeles"));
+            Date date = sdf.parse(dateStr);
+            
+            RFC3339DateFormat df = new RFC3339DateFormat();
+            StringBuffer sb = new StringBuffer();
+            String s = df.format(date);
+            assertEquals("2011-01-18T08:00:00.000Z", s);
+        }
+    }
+
     @Test
     public void testCustomDate() throws Exception {
         final DateTimeFormatter dateFormat = DateTimeFormatter.ISO_OFFSET_DATE_TIME.withZone(ZoneId.of("Etc/GMT+2"));
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/JSON.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/JSON.java
index be73bb23def..8f10d619a8f 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/JSON.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/JSON.java
@@ -59,10 +59,10 @@ public class JSON implements ContextResolver<ObjectMapper> {
    * @param node The input data.
    * @param modelClass The class that contains the discriminator mappings.
    */
-  public static Class getClassForElement(JsonNode node, Class modelClass) {
+  public static Class<?> getClassForElement(JsonNode node, Class<?> modelClass) {
     ClassDiscriminatorMapping cdm = modelDiscriminators.get(modelClass);
     if (cdm != null) {
-      return cdm.getClassForElement(node, new HashSet<Class>());
+      return cdm.getClassForElement(node, new HashSet<Class<?>>());
     }
     return null;
   }
@@ -72,17 +72,17 @@ public class JSON implements ContextResolver<ObjectMapper> {
    */
   private static class ClassDiscriminatorMapping {
     // The model class name.
-    Class modelClass;
+    Class<?> modelClass;
     // The name of the discriminator property.
     String discriminatorName;
     // The discriminator mappings for a model class.
-    Map<String, Class> discriminatorMappings;
+    Map<String, Class<?>> discriminatorMappings;
 
     // Constructs a new class discriminator.
-    ClassDiscriminatorMapping(Class cls, String propertyName, Map<String, Class> mappings) {
+    ClassDiscriminatorMapping(Class<?> cls, String propertyName, Map<String, Class<?>> mappings) {
       modelClass = cls;
       discriminatorName = propertyName;
-      discriminatorMappings = new HashMap<String, Class>();
+      discriminatorMappings = new HashMap<String, Class<?>>();
       if (mappings != null) {
         discriminatorMappings.putAll(mappings);
       }
@@ -118,7 +118,7 @@ public class JSON implements ContextResolver<ObjectMapper> {
      * @param node The input data.
      * @param visitedClasses The set of classes that have already been visited.
      */
-    Class getClassForElement(JsonNode node, Set<Class> visitedClasses) {
+    Class<?> getClassForElement(JsonNode node, Set<Class<?>> visitedClasses) {
       if (visitedClasses.contains(modelClass)) {
         // Class has already been visited.
         return null;
@@ -128,11 +128,11 @@ public class JSON implements ContextResolver<ObjectMapper> {
       if (discrValue == null) {
         return null;
       }
-      Class cls = discriminatorMappings.get(discrValue);
+      Class<?> cls = discriminatorMappings.get(discrValue);
       // It may not be sufficient to return this cls directly because that target class
       // may itself be a composed schema, possibly with its own discriminator.
       visitedClasses.add(modelClass);
-      for (Class childClass : discriminatorMappings.values()) {
+      for (Class<?> childClass : discriminatorMappings.values()) {
         ClassDiscriminatorMapping childCdm = modelDiscriminators.get(childClass);
         if (childCdm == null) {
           continue;
@@ -145,7 +145,7 @@ public class JSON implements ContextResolver<ObjectMapper> {
         }
         if (childCdm != null) {
           // Recursively traverse the discriminator mappings.
-          Class childDiscr = childCdm.getClassForElement(node, visitedClasses);
+          Class<?> childDiscr = childCdm.getClassForElement(node, visitedClasses);
           if (childDiscr != null) {
             return childDiscr;
           }
@@ -164,7 +164,7 @@ public class JSON implements ContextResolver<ObjectMapper> {
    * @param modelClass A OpenAPI model class.
    * @param inst The instance object.
    */
-  public static boolean isInstanceOf(Class modelClass, Object inst, Set<Class> visitedClasses) {
+  public static boolean isInstanceOf(Class<?> modelClass, Object inst, Set<Class<?>> visitedClasses) {
     if (modelClass.isInstance(inst)) {
       // This handles the 'allOf' use case with single parent inheritance.
       return true;
@@ -191,12 +191,12 @@ public class JSON implements ContextResolver<ObjectMapper> {
   /**
    * A map of discriminators for all model classes.
    */
-  private static Map<Class, ClassDiscriminatorMapping> modelDiscriminators = new HashMap<Class, ClassDiscriminatorMapping>();
+  private static Map<Class<?>, ClassDiscriminatorMapping> modelDiscriminators = new HashMap<Class<?>, ClassDiscriminatorMapping>();
 
   /**
    * A map of oneOf/anyOf descendants for each model class.
    */
-  private static Map<Class, Map<String, GenericType>> modelDescendants = new HashMap<Class, Map<String, GenericType>>();
+  private static Map<Class<?>, Map<String, GenericType>> modelDescendants = new HashMap<Class<?>, Map<String, GenericType>>();
 
   /**
     * Register a model class discriminator.
@@ -205,7 +205,7 @@ public class JSON implements ContextResolver<ObjectMapper> {
     * @param discriminatorPropertyName the name of the discriminator property
     * @param mappings a map with the discriminator mappings.
     */
-  public static void registerDiscriminator(Class modelClass, String discriminatorPropertyName, Map<String, Class> mappings) {
+  public static void registerDiscriminator(Class<?> modelClass, String discriminatorPropertyName, Map<String, Class<?>> mappings) {
     ClassDiscriminatorMapping m = new ClassDiscriminatorMapping(modelClass, discriminatorPropertyName, mappings);
     modelDiscriminators.put(modelClass, m);
   }
@@ -216,7 +216,7 @@ public class JSON implements ContextResolver<ObjectMapper> {
     * @param modelClass the model class
     * @param descendants a map of oneOf/anyOf descendants.
     */
-  public static void registerDescendants(Class modelClass, Map<String, GenericType> descendants) {
+  public static void registerDescendants(Class<?> modelClass, Map<String, GenericType> descendants) {
     modelDescendants.put(modelClass, descendants);
   }
 
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Animal.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Animal.java
index db0f8292bc3..bf2bc9d44c6 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Animal.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Animal.java
@@ -142,7 +142,7 @@ public class Animal {
 
 static {
   // Initialize and register the discriminator mappings.
-  Map<String, Class> mappings = new HashMap<String, Class>();
+  Map<String, Class<?>> mappings = new HashMap<String, Class<?>>();
   mappings.put("Cat", Cat.class);
   mappings.put("Dog", Dog.class);
   mappings.put("Animal", Animal.class);
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Cat.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Cat.java
index e36acce48e1..5d8e46c2b9a 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Cat.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Cat.java
@@ -113,7 +113,7 @@ public class Cat extends Animal {
 
 static {
   // Initialize and register the discriminator mappings.
-  Map<String, Class> mappings = new HashMap<String, Class>();
+  Map<String, Class<?>> mappings = new HashMap<String, Class<?>>();
   mappings.put("Cat", Cat.class);
   JSON.registerDiscriminator(Cat.class, "className", mappings);
 }
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/ChildCat.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/ChildCat.java
index 78b9503b885..5d2a29fb105 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/ChildCat.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/ChildCat.java
@@ -113,7 +113,7 @@ public class ChildCat extends ParentPet {
 
 static {
   // Initialize and register the discriminator mappings.
-  Map<String, Class> mappings = new HashMap<String, Class>();
+  Map<String, Class<?>> mappings = new HashMap<String, Class<?>>();
   mappings.put("ChildCat", ChildCat.class);
   JSON.registerDiscriminator(ChildCat.class, "pet_type", mappings);
 }
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Dog.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Dog.java
index 6166619f5f9..4b78ba6694b 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Dog.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Dog.java
@@ -113,7 +113,7 @@ public class Dog extends Animal {
 
 static {
   // Initialize and register the discriminator mappings.
-  Map<String, Class> mappings = new HashMap<String, Class>();
+  Map<String, Class<?>> mappings = new HashMap<String, Class<?>>();
   mappings.put("Dog", Dog.class);
   JSON.registerDiscriminator(Dog.class, "className", mappings);
 }
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Fruit.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Fruit.java
index 8a29dc7f946..b0923a6387c 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Fruit.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Fruit.java
@@ -129,7 +129,7 @@ public class Fruit extends AbstractOpenApiSchema {
          */
         @Override
         public Fruit getNullValue(DeserializationContext ctxt) throws JsonMappingException {
-            throw new JsonMappingException("Fruit cannot be null");
+            throw new JsonMappingException(ctxt.getParser(), "Fruit cannot be null");
         }
     }
 
@@ -172,12 +172,12 @@ public class Fruit extends AbstractOpenApiSchema {
      */
     @Override
     public void setActualInstance(Object instance) {
-        if (JSON.isInstanceOf(Apple.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf(Apple.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
 
-        if (JSON.isInstanceOf(Banana.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf(Banana.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/FruitReq.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/FruitReq.java
index cb55ce9a881..c02f4fc08ce 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/FruitReq.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/FruitReq.java
@@ -177,12 +177,12 @@ public class FruitReq extends AbstractOpenApiSchema {
            return;
         }
 
-        if (JSON.isInstanceOf(AppleReq.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf(AppleReq.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
 
-        if (JSON.isInstanceOf(BananaReq.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf(BananaReq.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/GmFruit.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/GmFruit.java
index 97c641fbc32..8a864854ea4 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/GmFruit.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/GmFruit.java
@@ -119,7 +119,7 @@ public class GmFruit extends AbstractOpenApiSchema {
          */
         @Override
         public GmFruit getNullValue(DeserializationContext ctxt) throws JsonMappingException {
-            throw new JsonMappingException("GmFruit cannot be null");
+            throw new JsonMappingException(ctxt.getParser(), "GmFruit cannot be null");
         }
     }
 
@@ -155,12 +155,12 @@ public class GmFruit extends AbstractOpenApiSchema {
 
     @Override
     public void setActualInstance(Object instance) {
-        if (JSON.isInstanceOf(Apple.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf(Apple.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
 
-        if (JSON.isInstanceOf(Banana.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf(Banana.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/GrandparentAnimal.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/GrandparentAnimal.java
index 103132148d5..32b63a840bd 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/GrandparentAnimal.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/GrandparentAnimal.java
@@ -112,7 +112,7 @@ public class GrandparentAnimal {
 
 static {
   // Initialize and register the discriminator mappings.
-  Map<String, Class> mappings = new HashMap<String, Class>();
+  Map<String, Class<?>> mappings = new HashMap<String, Class<?>>();
   mappings.put("ChildCat", ChildCat.class);
   mappings.put("ParentPet", ParentPet.class);
   mappings.put("GrandparentAnimal", GrandparentAnimal.class);
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Mammal.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Mammal.java
index 76b76934df9..225649b1b06 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Mammal.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Mammal.java
@@ -164,7 +164,7 @@ public class Mammal extends AbstractOpenApiSchema {
          */
         @Override
         public Mammal getNullValue(DeserializationContext ctxt) throws JsonMappingException {
-            throw new JsonMappingException("Mammal cannot be null");
+            throw new JsonMappingException(ctxt.getParser(), "Mammal cannot be null");
         }
     }
 
@@ -199,7 +199,7 @@ public class Mammal extends AbstractOpenApiSchema {
         });
         JSON.registerDescendants(Mammal.class, Collections.unmodifiableMap(schemas));
         // Initialize and register the discriminator mappings.
-        Map<String, Class> mappings = new HashMap<String, Class>();
+        Map<String, Class<?>> mappings = new HashMap<String, Class<?>>();
         mappings.put("Pig", Pig.class);
         mappings.put("whale", Whale.class);
         mappings.put("zebra", Zebra.class);
@@ -221,17 +221,17 @@ public class Mammal extends AbstractOpenApiSchema {
      */
     @Override
     public void setActualInstance(Object instance) {
-        if (JSON.isInstanceOf(Pig.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf(Pig.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
 
-        if (JSON.isInstanceOf(Whale.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf(Whale.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
 
-        if (JSON.isInstanceOf(Zebra.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf(Zebra.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/NullableShape.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/NullableShape.java
index 075a16bcd5e..75fc602d350 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/NullableShape.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/NullableShape.java
@@ -174,7 +174,7 @@ public class NullableShape extends AbstractOpenApiSchema {
         });
         JSON.registerDescendants(NullableShape.class, Collections.unmodifiableMap(schemas));
         // Initialize and register the discriminator mappings.
-        Map<String, Class> mappings = new HashMap<String, Class>();
+        Map<String, Class<?>> mappings = new HashMap<String, Class<?>>();
         mappings.put("Quadrilateral", Quadrilateral.class);
         mappings.put("Triangle", Triangle.class);
         mappings.put("NullableShape", NullableShape.class);
@@ -200,12 +200,12 @@ public class NullableShape extends AbstractOpenApiSchema {
            return;
         }
 
-        if (JSON.isInstanceOf(Quadrilateral.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf(Quadrilateral.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
 
-        if (JSON.isInstanceOf(Triangle.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf(Triangle.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/ParentPet.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/ParentPet.java
index 31c07e78a44..0ccaa50f6a4 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/ParentPet.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/ParentPet.java
@@ -83,7 +83,7 @@ public class ParentPet extends GrandparentAnimal {
 
 static {
   // Initialize and register the discriminator mappings.
-  Map<String, Class> mappings = new HashMap<String, Class>();
+  Map<String, Class<?>> mappings = new HashMap<String, Class<?>>();
   mappings.put("ChildCat", ChildCat.class);
   mappings.put("ParentPet", ParentPet.class);
   JSON.registerDiscriminator(ParentPet.class, "pet_type", mappings);
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Pig.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Pig.java
index 8b60edc0862..fccc724f5b0 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Pig.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Pig.java
@@ -146,7 +146,7 @@ public class Pig extends AbstractOpenApiSchema {
          */
         @Override
         public Pig getNullValue(DeserializationContext ctxt) throws JsonMappingException {
-            throw new JsonMappingException("Pig cannot be null");
+            throw new JsonMappingException(ctxt.getParser(), "Pig cannot be null");
         }
     }
 
@@ -174,7 +174,7 @@ public class Pig extends AbstractOpenApiSchema {
         });
         JSON.registerDescendants(Pig.class, Collections.unmodifiableMap(schemas));
         // Initialize and register the discriminator mappings.
-        Map<String, Class> mappings = new HashMap<String, Class>();
+        Map<String, Class<?>> mappings = new HashMap<String, Class<?>>();
         mappings.put("BasquePig", BasquePig.class);
         mappings.put("DanishPig", DanishPig.class);
         mappings.put("Pig", Pig.class);
@@ -195,12 +195,12 @@ public class Pig extends AbstractOpenApiSchema {
      */
     @Override
     public void setActualInstance(Object instance) {
-        if (JSON.isInstanceOf(BasquePig.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf(BasquePig.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
 
-        if (JSON.isInstanceOf(DanishPig.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf(DanishPig.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Quadrilateral.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Quadrilateral.java
index 61ad4f196df..a18e18a90f6 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Quadrilateral.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Quadrilateral.java
@@ -146,7 +146,7 @@ public class Quadrilateral extends AbstractOpenApiSchema {
          */
         @Override
         public Quadrilateral getNullValue(DeserializationContext ctxt) throws JsonMappingException {
-            throw new JsonMappingException("Quadrilateral cannot be null");
+            throw new JsonMappingException(ctxt.getParser(), "Quadrilateral cannot be null");
         }
     }
 
@@ -174,7 +174,7 @@ public class Quadrilateral extends AbstractOpenApiSchema {
         });
         JSON.registerDescendants(Quadrilateral.class, Collections.unmodifiableMap(schemas));
         // Initialize and register the discriminator mappings.
-        Map<String, Class> mappings = new HashMap<String, Class>();
+        Map<String, Class<?>> mappings = new HashMap<String, Class<?>>();
         mappings.put("ComplexQuadrilateral", ComplexQuadrilateral.class);
         mappings.put("SimpleQuadrilateral", SimpleQuadrilateral.class);
         mappings.put("Quadrilateral", Quadrilateral.class);
@@ -195,12 +195,12 @@ public class Quadrilateral extends AbstractOpenApiSchema {
      */
     @Override
     public void setActualInstance(Object instance) {
-        if (JSON.isInstanceOf(ComplexQuadrilateral.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf(ComplexQuadrilateral.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
 
-        if (JSON.isInstanceOf(SimpleQuadrilateral.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf(SimpleQuadrilateral.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Shape.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Shape.java
index a6a4ee10957..d98d0f8b43f 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Shape.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Shape.java
@@ -146,7 +146,7 @@ public class Shape extends AbstractOpenApiSchema {
          */
         @Override
         public Shape getNullValue(DeserializationContext ctxt) throws JsonMappingException {
-            throw new JsonMappingException("Shape cannot be null");
+            throw new JsonMappingException(ctxt.getParser(), "Shape cannot be null");
         }
     }
 
@@ -174,7 +174,7 @@ public class Shape extends AbstractOpenApiSchema {
         });
         JSON.registerDescendants(Shape.class, Collections.unmodifiableMap(schemas));
         // Initialize and register the discriminator mappings.
-        Map<String, Class> mappings = new HashMap<String, Class>();
+        Map<String, Class<?>> mappings = new HashMap<String, Class<?>>();
         mappings.put("Quadrilateral", Quadrilateral.class);
         mappings.put("Triangle", Triangle.class);
         mappings.put("Shape", Shape.class);
@@ -195,12 +195,12 @@ public class Shape extends AbstractOpenApiSchema {
      */
     @Override
     public void setActualInstance(Object instance) {
-        if (JSON.isInstanceOf(Quadrilateral.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf(Quadrilateral.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
 
-        if (JSON.isInstanceOf(Triangle.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf(Triangle.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/ShapeOrNull.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/ShapeOrNull.java
index 90eaed8b10e..baa4632c05c 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/ShapeOrNull.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/ShapeOrNull.java
@@ -174,7 +174,7 @@ public class ShapeOrNull extends AbstractOpenApiSchema {
         });
         JSON.registerDescendants(ShapeOrNull.class, Collections.unmodifiableMap(schemas));
         // Initialize and register the discriminator mappings.
-        Map<String, Class> mappings = new HashMap<String, Class>();
+        Map<String, Class<?>> mappings = new HashMap<String, Class<?>>();
         mappings.put("Quadrilateral", Quadrilateral.class);
         mappings.put("Triangle", Triangle.class);
         mappings.put("ShapeOrNull", ShapeOrNull.class);
@@ -200,12 +200,12 @@ public class ShapeOrNull extends AbstractOpenApiSchema {
            return;
         }
 
-        if (JSON.isInstanceOf(Quadrilateral.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf(Quadrilateral.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
 
-        if (JSON.isInstanceOf(Triangle.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf(Triangle.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Triangle.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Triangle.java
index de9e6af386c..d155a2c9601 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Triangle.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/model/Triangle.java
@@ -164,7 +164,7 @@ public class Triangle extends AbstractOpenApiSchema {
          */
         @Override
         public Triangle getNullValue(DeserializationContext ctxt) throws JsonMappingException {
-            throw new JsonMappingException("Triangle cannot be null");
+            throw new JsonMappingException(ctxt.getParser(), "Triangle cannot be null");
         }
     }
 
@@ -199,7 +199,7 @@ public class Triangle extends AbstractOpenApiSchema {
         });
         JSON.registerDescendants(Triangle.class, Collections.unmodifiableMap(schemas));
         // Initialize and register the discriminator mappings.
-        Map<String, Class> mappings = new HashMap<String, Class>();
+        Map<String, Class<?>> mappings = new HashMap<String, Class<?>>();
         mappings.put("EquilateralTriangle", EquilateralTriangle.class);
         mappings.put("IsoscelesTriangle", IsoscelesTriangle.class);
         mappings.put("ScaleneTriangle", ScaleneTriangle.class);
@@ -221,17 +221,17 @@ public class Triangle extends AbstractOpenApiSchema {
      */
     @Override
     public void setActualInstance(Object instance) {
-        if (JSON.isInstanceOf(EquilateralTriangle.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf(EquilateralTriangle.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
 
-        if (JSON.isInstanceOf(IsoscelesTriangle.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf(IsoscelesTriangle.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
 
-        if (JSON.isInstanceOf(ScaleneTriangle.class, instance, new HashSet<Class>())) {
+        if (JSON.isInstanceOf(ScaleneTriangle.class, instance, new HashSet<Class<?>>())) {
             super.setActualInstance(instance);
             return;
         }
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/test/java/org/openapitools/client/JSONComposedSchemaTest.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/test/java/org/openapitools/client/JSONComposedSchemaTest.java
index e2c11ad05de..a27cdbb7e6b 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/test/java/org/openapitools/client/JSONComposedSchemaTest.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/test/java/org/openapitools/client/JSONComposedSchemaTest.java
@@ -148,7 +148,7 @@ public class JSONComposedSchemaTest {
         Exception exception = assertThrows(JsonMappingException.class, () -> {
             json.getContext(null).readValue(str, Shape.class);
         });
-        assertEquals("Shape cannot be null", exception.getMessage());
+        assertTrue(exception.getMessage().contains("Shape cannot be null"));
     }
 
     /**
@@ -317,7 +317,7 @@ public class JSONComposedSchemaTest {
             Exception exception = assertThrows(JsonMappingException.class, () -> {
                 GmFruit o = json.getContext(null).readValue(str, GmFruit.class);
             });
-            assertEquals("GmFruit cannot be null", exception.getMessage());
+            assertTrue(exception.getMessage().contains("GmFruit cannot be null"));
         }  
     }
 }
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/test/java/org/openapitools/client/JSONTest.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/test/java/org/openapitools/client/JSONTest.java
index 7fb307a3df8..dda1ef9c1ef 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/test/java/org/openapitools/client/JSONTest.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/test/java/org/openapitools/client/JSONTest.java
@@ -3,7 +3,9 @@ package org.openapitools.client;
 import org.openapitools.client.model.Order;
 
 import java.lang.Exception;
-
+import java.util.Date;
+import java.util.TimeZone;
+import java.text.SimpleDateFormat;
 import java.time.OffsetDateTime;
 import java.time.ZoneId;
 import java.time.format.DateTimeFormatter;
@@ -32,6 +34,33 @@ public class JSONTest {
         assertEquals(dateStr, dateFormat.format(o.getShipDate()));
     }
 
+    @Test
+    public void testRFC3339DateFormatDate() throws Exception {
+        {
+            String dateStr = "2011-01-18 00:00:00.0Z";
+            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.S'Z'");
+            sdf.setTimeZone(TimeZone.getTimeZone("GMT"));
+            Date date = sdf.parse(dateStr);
+            
+            RFC3339DateFormat df = new RFC3339DateFormat();
+            StringBuffer sb = new StringBuffer();
+            String s = df.format(date);
+            System.out.println("DATE: " + s);
+            assertEquals("2011-01-18T00:00:00.000Z", s);
+        }
+        {
+            String dateStr = "2011-01-18 00:00:00.0";
+            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.S");
+            sdf.setTimeZone(TimeZone.getTimeZone("America/Los_Angeles"));
+            Date date = sdf.parse(dateStr);
+            
+            RFC3339DateFormat df = new RFC3339DateFormat();
+            StringBuffer sb = new StringBuffer();
+            String s = df.format(date);
+            assertEquals("2011-01-18T08:00:00.000Z", s);
+        }
+    }
+
     @Test
     public void testCustomDate() throws Exception {
         final DateTimeFormatter dateFormat = DateTimeFormatter.ISO_OFFSET_DATE_TIME.withZone(ZoneId.of("Etc/GMT+2"));