diff --git a/modules/openapi-generator-online/src/main/java/org/openapitools/codegen/online/RFC3339DateFormat.java b/modules/openapi-generator-online/src/main/java/org/openapitools/codegen/online/RFC3339DateFormat.java
index 9a089de40c361..fa2752bd6f8dc 100644
--- a/modules/openapi-generator-online/src/main/java/org/openapitools/codegen/online/RFC3339DateFormat.java
+++ b/modules/openapi-generator-online/src/main/java/org/openapitools/codegen/online/RFC3339DateFormat.java
@@ -17,35 +17,23 @@
 
 package org.openapitools.codegen.online;
 
-import com.fasterxml.jackson.databind.util.StdDateFormat;
+import com.fasterxml.jackson.databind.util.ISO8601DateFormat;
+import com.fasterxml.jackson.databind.util.ISO8601Utils;
 
-import java.text.DateFormat;
 import java.text.FieldPosition;
-import java.text.ParsePosition;
-import java.time.ZoneId;
-import java.time.ZoneOffset;
-import java.time.format.DateTimeFormatter;
 import java.util.Date;
-import java.util.TimeZone;
 
-public class RFC3339DateFormat extends DateFormat {
+
+public class RFC3339DateFormat extends ISO8601DateFormat {
 
   private static final long serialVersionUID = 1L;
-  private static final DateTimeFormatter dtf = DateTimeFormatter.ISO_OFFSET_DATE_TIME;
-  private static final StdDateFormat sdf = new StdDateFormat()
-      .withTimeZone(TimeZone.getTimeZone(ZoneId.systemDefault()))
-      .withColonInTimeZone(true);
 
+  // Same as ISO8601DateFormat but serializing milliseconds.
   @Override
   public StringBuffer format(Date date, StringBuffer toAppendTo, FieldPosition fieldPosition) {
-    String value = date.toInstant().atOffset(ZoneOffset.UTC).format(dtf);
+    String value = ISO8601Utils.format(date, true);
     toAppendTo.append(value);
     return toAppendTo;
   }
 
-  @Override
-  public Date parse(String source, ParsePosition pos) {
-    return sdf.parse(source, pos);
-  }
-
-}
+}
\ No newline at end of file
diff --git a/modules/openapi-generator/src/main/resources/Java/JSON.mustache b/modules/openapi-generator/src/main/resources/Java/JSON.mustache
index 0b4651d792823..1d0a8138787bb 100644
--- a/modules/openapi-generator/src/main/resources/Java/JSON.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/JSON.mustache
@@ -2,11 +2,11 @@
 
 package {{invokerPackage}};
 
-import com.fasterxml.jackson.databind.util.StdDateFormat;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonParseException;
 import com.google.gson.TypeAdapter;
+import com.google.gson.internal.bind.util.ISO8601Utils;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
 import com.google.gson.JsonElement;
@@ -33,14 +33,11 @@ import java.text.ParseException;
 import java.text.ParsePosition;
 import java.time.LocalDate;
 import java.time.OffsetDateTime;
-import java.time.ZoneOffset;
-import java.time.ZoneId;
 import java.time.format.DateTimeFormatter;
 import java.util.Date;
 import java.util.Locale;
 import java.util.Map;
 import java.util.HashMap;
-import java.util.TimeZone;
 
 public class JSON {
     private Gson gson;
@@ -57,11 +54,6 @@ public class JSON {
     {{/jsr310}}
     private ByteArrayAdapter byteArrayAdapter = new ByteArrayAdapter();
 
-    private static final StdDateFormat sdf = new StdDateFormat()
-        .withTimeZone(TimeZone.getTimeZone(ZoneId.systemDefault()))
-        .withColonInTimeZone(true);
-    private static final DateTimeFormatter dtf = DateTimeFormatter.ISO_OFFSET_DATE_TIME;
-
     @SuppressWarnings("unchecked")
     public static GsonBuilder createGson() {
         GsonFireBuilder fireBuilder = new GsonFireBuilder()
@@ -469,7 +461,7 @@ public class JSON {
                         if (dateFormat != null) {
                             return new java.sql.Date(dateFormat.parse(date).getTime());
                         }
-                        return new java.sql.Date(sdf.parse(date).getTime());
+                        return new java.sql.Date(ISO8601Utils.parse(date, new ParsePosition(0)).getTime());
                     } catch (ParseException e) {
                         throw new JsonParseException(e);
                     }
@@ -479,7 +471,7 @@ public class JSON {
 
     /**
      * Gson TypeAdapter for java.util.Date type
-     * If the dateFormat is null, DateTimeFormatter will be used.
+     * If the dateFormat is null, ISO8601Utils will be used.
      */
     public static class DateTypeAdapter extends TypeAdapter<Date> {
 
@@ -504,7 +496,7 @@ public class JSON {
                 if (dateFormat != null) {
                     value = dateFormat.format(date);
                 } else {
-                    value = date.toInstant().atOffset(ZoneOffset.UTC).format(dtf);
+                    value = ISO8601Utils.format(date, true);
                 }
                 out.value(value);
             }
@@ -523,7 +515,7 @@ public class JSON {
                             if (dateFormat != null) {
                                 return dateFormat.parse(date);
                             }
-                            return sdf.parse(date);
+                            return ISO8601Utils.parse(date, new ParsePosition(0));
                         } catch (ParseException e) {
                             throw new JsonParseException(e);
                         }
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/JSON.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/JSON.mustache
index c6075a086949a..6cf7ec7898c4c 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/JSON.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/JSON.mustache
@@ -2,11 +2,11 @@
 
 package {{invokerPackage}};
 
-import com.fasterxml.jackson.databind.util.StdDateFormat;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonParseException;
 import com.google.gson.TypeAdapter;
+import com.google.gson.internal.bind.util.ISO8601Utils;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
 import com.google.gson.JsonElement;
@@ -27,16 +27,14 @@ import java.io.StringReader;
 import java.lang.reflect.Type;
 import java.text.DateFormat;
 import java.text.ParseException;
+import java.text.ParsePosition;
 import java.time.LocalDate;
 import java.time.OffsetDateTime;
-import java.time.ZoneId;
-import java.time.ZoneOffset;
 import java.time.format.DateTimeFormatter;
 import java.util.Date;
 import java.util.Locale;
 import java.util.Map;
 import java.util.HashMap;
-import java.util.TimeZone;
 
 /*
  * A JSON utility class
@@ -59,11 +57,6 @@ public class JSON {
     {{/jsr310}}
     private static ByteArrayAdapter byteArrayAdapter = new ByteArrayAdapter();
 
-    private static final StdDateFormat sdf = new StdDateFormat()
-        .withTimeZone(TimeZone.getTimeZone(ZoneId.systemDefault()))
-        .withColonInTimeZone(true);
-    private static final DateTimeFormatter dtf = DateTimeFormatter.ISO_OFFSET_DATE_TIME;
-
     @SuppressWarnings("unchecked")
     public static GsonBuilder createGson() {
         GsonFireBuilder fireBuilder = new GsonFireBuilder()
@@ -466,7 +459,7 @@ public class JSON {
                         if (dateFormat != null) {
                             return new java.sql.Date(dateFormat.parse(date).getTime());
                         }
-                        return new java.sql.Date(sdf.parse(date).getTime());
+                        return new java.sql.Date(ISO8601Utils.parse(date, new ParsePosition(0)).getTime());
                     } catch (ParseException e) {
                         throw new JsonParseException(e);
                     }
@@ -476,7 +469,7 @@ public class JSON {
 
     /**
      * Gson TypeAdapter for java.util.Date type
-     * If the dateFormat is null, DateTimeFormatter will be used.
+     * If the dateFormat is null, ISO8601Utils will be used.
      */
     public static class DateTypeAdapter extends TypeAdapter<Date> {
 
@@ -501,7 +494,7 @@ public class JSON {
                 if (dateFormat != null) {
                     value = dateFormat.format(date);
                 } else {
-                    value = date.toInstant().atOffset(ZoneOffset.UTC).format(dtf);
+                    value = ISO8601Utils.format(date, true);
                 }
                 out.value(value);
             }
@@ -520,7 +513,7 @@ public class JSON {
                             if (dateFormat != null) {
                                 return dateFormat.parse(date);
                             }
-                            return sdf.parse(date);
+                            return ISO8601Utils.parse(date, new ParsePosition(0));
                         } catch (ParseException e) {
                             throw new JsonParseException(e);
                         }
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/rest-assured/pom.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/rest-assured/pom.mustache
index a892488a245ad..1c8e41ee0242b 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/rest-assured/pom.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/rest-assured/pom.mustache
@@ -271,11 +271,6 @@
             <version>${gson-fire-version}</version>
         </dependency>
         {{/gson}}
-        <dependency>
-            <groupId>com.fasterxml.jackson.core</groupId>
-            <artifactId>jackson-databind</artifactId>
-            <version>${jackson-databind-version}</version>
-        </dependency>
         {{#jackson}}
         <!-- JSON processing: jackson -->
         <dependency>
@@ -286,6 +281,10 @@
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-annotations</artifactId>
         </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+        </dependency>
         <dependency>
             <groupId>org.openapitools</groupId>
             <artifactId>jackson-databind-nullable</artifactId>
@@ -352,9 +351,9 @@
         {{#joda}}
         <jodatime-version>2.10.5</jodatime-version>
         {{/joda}}
-        <jackson-databind-version>2.15.2</jackson-databind-version>
         {{#jackson}}
         <jackson-version>2.15.2</jackson-version>
+        <jackson-databind-version>2.15.2</jackson-databind-version>
         <jackson-databind-nullable-version>0.2.6</jackson-databind-nullable-version>
         {{/jackson}}
         {{#useJakartaEe}}
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/retrofit2/JSON.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/retrofit2/JSON.mustache
index 2d791d4ff5880..2ff8b1cb739c7 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/retrofit2/JSON.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/retrofit2/JSON.mustache
@@ -2,11 +2,11 @@
 
 package {{invokerPackage}};
 
-import com.fasterxml.jackson.databind.util.StdDateFormat;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonParseException;
 import com.google.gson.TypeAdapter;
+import com.google.gson.internal.bind.util.ISO8601Utils;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
 import com.google.gson.JsonElement;
@@ -32,14 +32,11 @@ import java.text.ParseException;
 import java.text.ParsePosition;
 import java.time.LocalDate;
 import java.time.OffsetDateTime;
-import java.time.ZoneOffset;
-import java.time.ZoneId;
 import java.time.format.DateTimeFormatter;
 import java.util.Date;
 import java.util.Locale;
 import java.util.Map;
 import java.util.HashMap;
-import java.util.TimeZone;
 
 public class JSON {
     private Gson gson;
@@ -54,11 +51,6 @@ public class JSON {
     private LocalDateTypeAdapter localDateTypeAdapter = new LocalDateTypeAdapter();
     {{/jsr310}}
 
-    private static final StdDateFormat sdf = new StdDateFormat()
-        .withTimeZone(TimeZone.getTimeZone(ZoneId.systemDefault()))
-        .withColonInTimeZone(true);
-    private static final DateTimeFormatter dtf = DateTimeFormatter.ISO_OFFSET_DATE_TIME;
-
     public static GsonBuilder createGson() {
         GsonFireBuilder fireBuilder = new GsonFireBuilder()
         {{#models}}{{#model}}{{#discriminator}}  .registerTypeSelector({{classname}}.class, new TypeSelector() {
@@ -370,7 +362,7 @@ public class JSON {
                         if (dateFormat != null) {
                             return new java.sql.Date(dateFormat.parse(date).getTime());
                         }
-                        return new java.sql.Date(sdf.parse(date).getTime());
+                        return new java.sql.Date(ISO8601Utils.parse(date, new ParsePosition(0)).getTime());
                     } catch (ParseException e) {
                         throw new JsonParseException(e);
                     }
@@ -380,7 +372,7 @@ public class JSON {
 
     /**
      * Gson TypeAdapter for java.util.Date type
-     * If the dateFormat is null, DateTimeFormatter will be used.
+     * If the dateFormat is null, ISO8601Utils will be used.
      */
     public static class DateTypeAdapter extends TypeAdapter<Date> {
 
@@ -406,7 +398,7 @@ public class JSON {
                 if (dateFormat != null) {
                     value = dateFormat.format(date);
                 } else {
-                    value = date.toInstant().atOffset(ZoneOffset.UTC).format(dtf);
+                    value = ISO8601Utils.format(date, true);
                 }
                 out.value(value);
             }
@@ -425,7 +417,7 @@ public class JSON {
                             if (dateFormat != null) {
                                 return dateFormat.parse(date);
                             }
-                            return sdf.parse(date);
+                            return ISO8601Utils.parse(date, new ParsePosition(0));
                         } catch (ParseException e) {
                             throw new JsonParseException(e);
                         }
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/retrofit2/pom.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/retrofit2/pom.mustache
index 20b5c80c7c244..a610e2bd31630 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/retrofit2/pom.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/retrofit2/pom.mustache
@@ -305,6 +305,11 @@
                 <artifactId>jackson-annotations</artifactId>
                 <version>${jackson-version}</version>
             </dependency>
+            <dependency>
+                <groupId>com.fasterxml.jackson.core</groupId>
+                <artifactId>jackson-databind</artifactId>
+                <version>${jackson-databind-version}</version>
+            </dependency>
             {{#openApiNullable}}
             <dependency>
                 <groupId>org.openapitools</groupId>
@@ -344,6 +349,11 @@
                 <artifactId>play-ahc-ws_2.12</artifactId>
                 <version>${play-version}</version>
             </dependency>
+            <dependency>
+                <groupId>jakarta.validation</groupId>
+                <artifactId>jakarta.validation-api</artifactId>
+                <version>${beanvalidation-version}</version>
+            </dependency>
         {{/usePlayWS}}
         {{#parcelableModel}}
             <!-- Needed for Parcelable support-->
@@ -377,12 +387,12 @@
         <gson-fire-version>1.9.0</gson-fire-version>
         {{/gson}}
         <swagger-annotations-version>1.6.3</swagger-annotations-version>
-        <jackson-databind-version>2.15.2</jackson-databind-version>
         {{#jackson}}
+        <jackson-databind-version>2.15.2</jackson-databind-version>
         <jackson-version>2.15.2</jackson-version>
-        {{#openApiNullable}}
+            {{#openApiNullable}}
         <jackson-databind-nullable-version>0.2.6</jackson-databind-nullable-version>
-        {{/openApiNullable}}
+            {{/openApiNullable}}
         <javax.ws.rs-api-version>2.1.1</javax.ws.rs-api-version>
         {{/jackson}}
         {{#usePlayWS}}
diff --git a/samples/client/echo_api/java/okhttp-gson/src/main/java/org/openapitools/client/JSON.java b/samples/client/echo_api/java/okhttp-gson/src/main/java/org/openapitools/client/JSON.java
index 1520a2c935731..247f3cf0c99c6 100644
--- a/samples/client/echo_api/java/okhttp-gson/src/main/java/org/openapitools/client/JSON.java
+++ b/samples/client/echo_api/java/okhttp-gson/src/main/java/org/openapitools/client/JSON.java
@@ -13,11 +13,11 @@
 
 package org.openapitools.client;
 
-import com.fasterxml.jackson.databind.util.StdDateFormat;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonParseException;
 import com.google.gson.TypeAdapter;
+import com.google.gson.internal.bind.util.ISO8601Utils;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
 import com.google.gson.JsonElement;
@@ -31,16 +31,14 @@
 import java.lang.reflect.Type;
 import java.text.DateFormat;
 import java.text.ParseException;
+import java.text.ParsePosition;
 import java.time.LocalDate;
 import java.time.OffsetDateTime;
-import java.time.ZoneId;
-import java.time.ZoneOffset;
 import java.time.format.DateTimeFormatter;
 import java.util.Date;
 import java.util.Locale;
 import java.util.Map;
 import java.util.HashMap;
-import java.util.TimeZone;
 
 /*
  * A JSON utility class
@@ -57,11 +55,6 @@ public class JSON {
     private static LocalDateTypeAdapter localDateTypeAdapter = new LocalDateTypeAdapter();
     private static ByteArrayAdapter byteArrayAdapter = new ByteArrayAdapter();
 
-    private static final StdDateFormat sdf = new StdDateFormat()
-        .withTimeZone(TimeZone.getTimeZone(ZoneId.systemDefault()))
-        .withColonInTimeZone(true);
-    private static final DateTimeFormatter dtf = DateTimeFormatter.ISO_OFFSET_DATE_TIME;
-
     @SuppressWarnings("unchecked")
     public static GsonBuilder createGson() {
         GsonFireBuilder fireBuilder = new GsonFireBuilder()
@@ -342,7 +335,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
                         if (dateFormat != null) {
                             return new java.sql.Date(dateFormat.parse(date).getTime());
                         }
-                        return new java.sql.Date(sdf.parse(date).getTime());
+                        return new java.sql.Date(ISO8601Utils.parse(date, new ParsePosition(0)).getTime());
                     } catch (ParseException e) {
                         throw new JsonParseException(e);
                     }
@@ -352,7 +345,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
 
     /**
      * Gson TypeAdapter for java.util.Date type
-     * If the dateFormat is null, DateTimeFormatter will be used.
+     * If the dateFormat is null, ISO8601Utils will be used.
      */
     public static class DateTypeAdapter extends TypeAdapter<Date> {
 
@@ -377,7 +370,7 @@ public void write(JsonWriter out, Date date) throws IOException {
                 if (dateFormat != null) {
                     value = dateFormat.format(date);
                 } else {
-                    value = date.toInstant().atOffset(ZoneOffset.UTC).format(dtf);
+                    value = ISO8601Utils.format(date, true);
                 }
                 out.value(value);
             }
@@ -396,7 +389,7 @@ public Date read(JsonReader in) throws IOException {
                             if (dateFormat != null) {
                                 return dateFormat.parse(date);
                             }
-                            return sdf.parse(date);
+                            return ISO8601Utils.parse(date, new ParsePosition(0));
                         } catch (ParseException e) {
                             throw new JsonParseException(e);
                         }
diff --git a/samples/client/others/java/okhttp-gson-oneOf/src/main/java/org/openapitools/client/JSON.java b/samples/client/others/java/okhttp-gson-oneOf/src/main/java/org/openapitools/client/JSON.java
index f4e972e414e08..c6b151d0ccc0e 100644
--- a/samples/client/others/java/okhttp-gson-oneOf/src/main/java/org/openapitools/client/JSON.java
+++ b/samples/client/others/java/okhttp-gson-oneOf/src/main/java/org/openapitools/client/JSON.java
@@ -13,11 +13,11 @@
 
 package org.openapitools.client;
 
-import com.fasterxml.jackson.databind.util.StdDateFormat;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonParseException;
 import com.google.gson.TypeAdapter;
+import com.google.gson.internal.bind.util.ISO8601Utils;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
 import com.google.gson.JsonElement;
@@ -31,16 +31,14 @@
 import java.lang.reflect.Type;
 import java.text.DateFormat;
 import java.text.ParseException;
+import java.text.ParsePosition;
 import java.time.LocalDate;
 import java.time.OffsetDateTime;
-import java.time.ZoneId;
-import java.time.ZoneOffset;
 import java.time.format.DateTimeFormatter;
 import java.util.Date;
 import java.util.Locale;
 import java.util.Map;
 import java.util.HashMap;
-import java.util.TimeZone;
 
 /*
  * A JSON utility class
@@ -57,11 +55,6 @@ public class JSON {
     private static LocalDateTypeAdapter localDateTypeAdapter = new LocalDateTypeAdapter();
     private static ByteArrayAdapter byteArrayAdapter = new ByteArrayAdapter();
 
-    private static final StdDateFormat sdf = new StdDateFormat()
-        .withTimeZone(TimeZone.getTimeZone(ZoneId.systemDefault()))
-        .withColonInTimeZone(true);
-    private static final DateTimeFormatter dtf = DateTimeFormatter.ISO_OFFSET_DATE_TIME;
-
     @SuppressWarnings("unchecked")
     public static GsonBuilder createGson() {
         GsonFireBuilder fireBuilder = new GsonFireBuilder()
@@ -333,7 +326,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
                         if (dateFormat != null) {
                             return new java.sql.Date(dateFormat.parse(date).getTime());
                         }
-                        return new java.sql.Date(sdf.parse(date).getTime());
+                        return new java.sql.Date(ISO8601Utils.parse(date, new ParsePosition(0)).getTime());
                     } catch (ParseException e) {
                         throw new JsonParseException(e);
                     }
@@ -343,7 +336,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
 
     /**
      * Gson TypeAdapter for java.util.Date type
-     * If the dateFormat is null, DateTimeFormatter will be used.
+     * If the dateFormat is null, ISO8601Utils will be used.
      */
     public static class DateTypeAdapter extends TypeAdapter<Date> {
 
@@ -368,7 +361,7 @@ public void write(JsonWriter out, Date date) throws IOException {
                 if (dateFormat != null) {
                     value = dateFormat.format(date);
                 } else {
-                    value = date.toInstant().atOffset(ZoneOffset.UTC).format(dtf);
+                    value = ISO8601Utils.format(date, true);
                 }
                 out.value(value);
             }
@@ -387,7 +380,7 @@ public Date read(JsonReader in) throws IOException {
                             if (dateFormat != null) {
                                 return dateFormat.parse(date);
                             }
-                            return sdf.parse(date);
+                            return ISO8601Utils.parse(date, new ParsePosition(0));
                         } catch (ParseException e) {
                             throw new JsonParseException(e);
                         }
diff --git a/samples/client/others/java/okhttp-gson-streaming/src/main/java/org/openapitools/client/JSON.java b/samples/client/others/java/okhttp-gson-streaming/src/main/java/org/openapitools/client/JSON.java
index 2aac67fb5b2b1..999628dc1f76f 100644
--- a/samples/client/others/java/okhttp-gson-streaming/src/main/java/org/openapitools/client/JSON.java
+++ b/samples/client/others/java/okhttp-gson-streaming/src/main/java/org/openapitools/client/JSON.java
@@ -13,11 +13,11 @@
 
 package org.openapitools.client;
 
-import com.fasterxml.jackson.databind.util.StdDateFormat;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonParseException;
 import com.google.gson.TypeAdapter;
+import com.google.gson.internal.bind.util.ISO8601Utils;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
 import com.google.gson.JsonElement;
@@ -31,16 +31,14 @@
 import java.lang.reflect.Type;
 import java.text.DateFormat;
 import java.text.ParseException;
+import java.text.ParsePosition;
 import java.time.LocalDate;
 import java.time.OffsetDateTime;
-import java.time.ZoneId;
-import java.time.ZoneOffset;
 import java.time.format.DateTimeFormatter;
 import java.util.Date;
 import java.util.Locale;
 import java.util.Map;
 import java.util.HashMap;
-import java.util.TimeZone;
 
 /*
  * A JSON utility class
@@ -57,11 +55,6 @@ public class JSON {
     private static LocalDateTypeAdapter localDateTypeAdapter = new LocalDateTypeAdapter();
     private static ByteArrayAdapter byteArrayAdapter = new ByteArrayAdapter();
 
-    private static final StdDateFormat sdf = new StdDateFormat()
-        .withTimeZone(TimeZone.getTimeZone(ZoneId.systemDefault()))
-        .withColonInTimeZone(true);
-    private static final DateTimeFormatter dtf = DateTimeFormatter.ISO_OFFSET_DATE_TIME;
-
     @SuppressWarnings("unchecked")
     public static GsonBuilder createGson() {
         GsonFireBuilder fireBuilder = new GsonFireBuilder()
@@ -334,7 +327,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
                         if (dateFormat != null) {
                             return new java.sql.Date(dateFormat.parse(date).getTime());
                         }
-                        return new java.sql.Date(sdf.parse(date).getTime());
+                        return new java.sql.Date(ISO8601Utils.parse(date, new ParsePosition(0)).getTime());
                     } catch (ParseException e) {
                         throw new JsonParseException(e);
                     }
@@ -344,7 +337,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
 
     /**
      * Gson TypeAdapter for java.util.Date type
-     * If the dateFormat is null, DateTimeFormatter will be used.
+     * If the dateFormat is null, ISO8601Utils will be used.
      */
     public static class DateTypeAdapter extends TypeAdapter<Date> {
 
@@ -369,7 +362,7 @@ public void write(JsonWriter out, Date date) throws IOException {
                 if (dateFormat != null) {
                     value = dateFormat.format(date);
                 } else {
-                    value = date.toInstant().atOffset(ZoneOffset.UTC).format(dtf);
+                    value = ISO8601Utils.format(date, true);
                 }
                 out.value(value);
             }
@@ -388,7 +381,7 @@ public Date read(JsonReader in) throws IOException {
                             if (dateFormat != null) {
                                 return dateFormat.parse(date);
                             }
-                            return sdf.parse(date);
+                            return ISO8601Utils.parse(date, new ParsePosition(0));
                         } catch (ParseException e) {
                             throw new JsonParseException(e);
                         }
diff --git a/samples/client/petstore/java/okhttp-gson-3.1/src/main/java/org/openapitools/client/JSON.java b/samples/client/petstore/java/okhttp-gson-3.1/src/main/java/org/openapitools/client/JSON.java
index f5823fd752244..6fe26034d7ed1 100644
--- a/samples/client/petstore/java/okhttp-gson-3.1/src/main/java/org/openapitools/client/JSON.java
+++ b/samples/client/petstore/java/okhttp-gson-3.1/src/main/java/org/openapitools/client/JSON.java
@@ -13,11 +13,11 @@
 
 package org.openapitools.client;
 
-import com.fasterxml.jackson.databind.util.StdDateFormat;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonParseException;
 import com.google.gson.TypeAdapter;
+import com.google.gson.internal.bind.util.ISO8601Utils;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
 import com.google.gson.JsonElement;
@@ -31,16 +31,14 @@
 import java.lang.reflect.Type;
 import java.text.DateFormat;
 import java.text.ParseException;
+import java.text.ParsePosition;
 import java.time.LocalDate;
 import java.time.OffsetDateTime;
-import java.time.ZoneId;
-import java.time.ZoneOffset;
 import java.time.format.DateTimeFormatter;
 import java.util.Date;
 import java.util.Locale;
 import java.util.Map;
 import java.util.HashMap;
-import java.util.TimeZone;
 
 /*
  * A JSON utility class
@@ -57,11 +55,6 @@ public class JSON {
     private static LocalDateTypeAdapter localDateTypeAdapter = new LocalDateTypeAdapter();
     private static ByteArrayAdapter byteArrayAdapter = new ByteArrayAdapter();
 
-    private static final StdDateFormat sdf = new StdDateFormat()
-        .withTimeZone(TimeZone.getTimeZone(ZoneId.systemDefault()))
-        .withColonInTimeZone(true);
-    private static final DateTimeFormatter dtf = DateTimeFormatter.ISO_OFFSET_DATE_TIME;
-
     @SuppressWarnings("unchecked")
     public static GsonBuilder createGson() {
         GsonFireBuilder fireBuilder = new GsonFireBuilder()
@@ -378,7 +371,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
                         if (dateFormat != null) {
                             return new java.sql.Date(dateFormat.parse(date).getTime());
                         }
-                        return new java.sql.Date(sdf.parse(date).getTime());
+                        return new java.sql.Date(ISO8601Utils.parse(date, new ParsePosition(0)).getTime());
                     } catch (ParseException e) {
                         throw new JsonParseException(e);
                     }
@@ -388,7 +381,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
 
     /**
      * Gson TypeAdapter for java.util.Date type
-     * If the dateFormat is null, DateTimeFormatter will be used.
+     * If the dateFormat is null, ISO8601Utils will be used.
      */
     public static class DateTypeAdapter extends TypeAdapter<Date> {
 
@@ -413,7 +406,7 @@ public void write(JsonWriter out, Date date) throws IOException {
                 if (dateFormat != null) {
                     value = dateFormat.format(date);
                 } else {
-                    value = date.toInstant().atOffset(ZoneOffset.UTC).format(dtf);
+                    value = ISO8601Utils.format(date, true);
                 }
                 out.value(value);
             }
@@ -432,7 +425,7 @@ public Date read(JsonReader in) throws IOException {
                             if (dateFormat != null) {
                                 return dateFormat.parse(date);
                             }
-                            return sdf.parse(date);
+                            return ISO8601Utils.parse(date, new ParsePosition(0));
                         } catch (ParseException e) {
                             throw new JsonParseException(e);
                         }
diff --git a/samples/client/petstore/java/okhttp-gson-awsv4signature/src/main/java/org/openapitools/client/JSON.java b/samples/client/petstore/java/okhttp-gson-awsv4signature/src/main/java/org/openapitools/client/JSON.java
index ad2d26cbfbb76..f993e935c7aa4 100644
--- a/samples/client/petstore/java/okhttp-gson-awsv4signature/src/main/java/org/openapitools/client/JSON.java
+++ b/samples/client/petstore/java/okhttp-gson-awsv4signature/src/main/java/org/openapitools/client/JSON.java
@@ -13,11 +13,11 @@
 
 package org.openapitools.client;
 
-import com.fasterxml.jackson.databind.util.StdDateFormat;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonParseException;
 import com.google.gson.TypeAdapter;
+import com.google.gson.internal.bind.util.ISO8601Utils;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
 import com.google.gson.JsonElement;
@@ -31,16 +31,14 @@
 import java.lang.reflect.Type;
 import java.text.DateFormat;
 import java.text.ParseException;
+import java.text.ParsePosition;
 import java.time.LocalDate;
 import java.time.OffsetDateTime;
-import java.time.ZoneId;
-import java.time.ZoneOffset;
 import java.time.format.DateTimeFormatter;
 import java.util.Date;
 import java.util.Locale;
 import java.util.Map;
 import java.util.HashMap;
-import java.util.TimeZone;
 
 /*
  * A JSON utility class
@@ -57,11 +55,6 @@ public class JSON {
     private static LocalDateTypeAdapter localDateTypeAdapter = new LocalDateTypeAdapter();
     private static ByteArrayAdapter byteArrayAdapter = new ByteArrayAdapter();
 
-    private static final StdDateFormat sdf = new StdDateFormat()
-        .withTimeZone(TimeZone.getTimeZone(ZoneId.systemDefault()))
-        .withColonInTimeZone(true);
-    private static final DateTimeFormatter dtf = DateTimeFormatter.ISO_OFFSET_DATE_TIME;
-
     @SuppressWarnings("unchecked")
     public static GsonBuilder createGson() {
         GsonFireBuilder fireBuilder = new GsonFireBuilder()
@@ -338,7 +331,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
                         if (dateFormat != null) {
                             return new java.sql.Date(dateFormat.parse(date).getTime());
                         }
-                        return new java.sql.Date(sdf.parse(date).getTime());
+                        return new java.sql.Date(ISO8601Utils.parse(date, new ParsePosition(0)).getTime());
                     } catch (ParseException e) {
                         throw new JsonParseException(e);
                     }
@@ -348,7 +341,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
 
     /**
      * Gson TypeAdapter for java.util.Date type
-     * If the dateFormat is null, DateTimeFormatter will be used.
+     * If the dateFormat is null, ISO8601Utils will be used.
      */
     public static class DateTypeAdapter extends TypeAdapter<Date> {
 
@@ -373,7 +366,7 @@ public void write(JsonWriter out, Date date) throws IOException {
                 if (dateFormat != null) {
                     value = dateFormat.format(date);
                 } else {
-                    value = date.toInstant().atOffset(ZoneOffset.UTC).format(dtf);
+                    value = ISO8601Utils.format(date, true);
                 }
                 out.value(value);
             }
@@ -392,7 +385,7 @@ public Date read(JsonReader in) throws IOException {
                             if (dateFormat != null) {
                                 return dateFormat.parse(date);
                             }
-                            return sdf.parse(date);
+                            return ISO8601Utils.parse(date, new ParsePosition(0));
                         } catch (ParseException e) {
                             throw new JsonParseException(e);
                         }
diff --git a/samples/client/petstore/java/okhttp-gson-dynamicOperations/src/main/java/org/openapitools/client/JSON.java b/samples/client/petstore/java/okhttp-gson-dynamicOperations/src/main/java/org/openapitools/client/JSON.java
index 349f4ff81132a..6d80edba2a7bf 100644
--- a/samples/client/petstore/java/okhttp-gson-dynamicOperations/src/main/java/org/openapitools/client/JSON.java
+++ b/samples/client/petstore/java/okhttp-gson-dynamicOperations/src/main/java/org/openapitools/client/JSON.java
@@ -13,11 +13,11 @@
 
 package org.openapitools.client;
 
-import com.fasterxml.jackson.databind.util.StdDateFormat;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonParseException;
 import com.google.gson.TypeAdapter;
+import com.google.gson.internal.bind.util.ISO8601Utils;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
 import com.google.gson.JsonElement;
@@ -31,16 +31,14 @@
 import java.lang.reflect.Type;
 import java.text.DateFormat;
 import java.text.ParseException;
+import java.text.ParsePosition;
 import java.time.LocalDate;
 import java.time.OffsetDateTime;
-import java.time.ZoneId;
-import java.time.ZoneOffset;
 import java.time.format.DateTimeFormatter;
 import java.util.Date;
 import java.util.Locale;
 import java.util.Map;
 import java.util.HashMap;
-import java.util.TimeZone;
 
 /*
  * A JSON utility class
@@ -57,11 +55,6 @@ public class JSON {
     private static LocalDateTypeAdapter localDateTypeAdapter = new LocalDateTypeAdapter();
     private static ByteArrayAdapter byteArrayAdapter = new ByteArrayAdapter();
 
-    private static final StdDateFormat sdf = new StdDateFormat()
-        .withTimeZone(TimeZone.getTimeZone(ZoneId.systemDefault()))
-        .withColonInTimeZone(true);
-    private static final DateTimeFormatter dtf = DateTimeFormatter.ISO_OFFSET_DATE_TIME;
-
     @SuppressWarnings("unchecked")
     public static GsonBuilder createGson() {
         GsonFireBuilder fireBuilder = new GsonFireBuilder()
@@ -413,7 +406,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
                         if (dateFormat != null) {
                             return new java.sql.Date(dateFormat.parse(date).getTime());
                         }
-                        return new java.sql.Date(sdf.parse(date).getTime());
+                        return new java.sql.Date(ISO8601Utils.parse(date, new ParsePosition(0)).getTime());
                     } catch (ParseException e) {
                         throw new JsonParseException(e);
                     }
@@ -423,7 +416,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
 
     /**
      * Gson TypeAdapter for java.util.Date type
-     * If the dateFormat is null, DateTimeFormatter will be used.
+     * If the dateFormat is null, ISO8601Utils will be used.
      */
     public static class DateTypeAdapter extends TypeAdapter<Date> {
 
@@ -448,7 +441,7 @@ public void write(JsonWriter out, Date date) throws IOException {
                 if (dateFormat != null) {
                     value = dateFormat.format(date);
                 } else {
-                    value = date.toInstant().atOffset(ZoneOffset.UTC).format(dtf);
+                    value = ISO8601Utils.format(date, true);
                 }
                 out.value(value);
             }
@@ -467,7 +460,7 @@ public Date read(JsonReader in) throws IOException {
                             if (dateFormat != null) {
                                 return dateFormat.parse(date);
                             }
-                            return sdf.parse(date);
+                            return ISO8601Utils.parse(date, new ParsePosition(0));
                         } catch (ParseException e) {
                             throw new JsonParseException(e);
                         }
diff --git a/samples/client/petstore/java/okhttp-gson-group-parameter/src/main/java/org/openapitools/client/JSON.java b/samples/client/petstore/java/okhttp-gson-group-parameter/src/main/java/org/openapitools/client/JSON.java
index ad2d26cbfbb76..f993e935c7aa4 100644
--- a/samples/client/petstore/java/okhttp-gson-group-parameter/src/main/java/org/openapitools/client/JSON.java
+++ b/samples/client/petstore/java/okhttp-gson-group-parameter/src/main/java/org/openapitools/client/JSON.java
@@ -13,11 +13,11 @@
 
 package org.openapitools.client;
 
-import com.fasterxml.jackson.databind.util.StdDateFormat;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonParseException;
 import com.google.gson.TypeAdapter;
+import com.google.gson.internal.bind.util.ISO8601Utils;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
 import com.google.gson.JsonElement;
@@ -31,16 +31,14 @@
 import java.lang.reflect.Type;
 import java.text.DateFormat;
 import java.text.ParseException;
+import java.text.ParsePosition;
 import java.time.LocalDate;
 import java.time.OffsetDateTime;
-import java.time.ZoneId;
-import java.time.ZoneOffset;
 import java.time.format.DateTimeFormatter;
 import java.util.Date;
 import java.util.Locale;
 import java.util.Map;
 import java.util.HashMap;
-import java.util.TimeZone;
 
 /*
  * A JSON utility class
@@ -57,11 +55,6 @@ public class JSON {
     private static LocalDateTypeAdapter localDateTypeAdapter = new LocalDateTypeAdapter();
     private static ByteArrayAdapter byteArrayAdapter = new ByteArrayAdapter();
 
-    private static final StdDateFormat sdf = new StdDateFormat()
-        .withTimeZone(TimeZone.getTimeZone(ZoneId.systemDefault()))
-        .withColonInTimeZone(true);
-    private static final DateTimeFormatter dtf = DateTimeFormatter.ISO_OFFSET_DATE_TIME;
-
     @SuppressWarnings("unchecked")
     public static GsonBuilder createGson() {
         GsonFireBuilder fireBuilder = new GsonFireBuilder()
@@ -338,7 +331,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
                         if (dateFormat != null) {
                             return new java.sql.Date(dateFormat.parse(date).getTime());
                         }
-                        return new java.sql.Date(sdf.parse(date).getTime());
+                        return new java.sql.Date(ISO8601Utils.parse(date, new ParsePosition(0)).getTime());
                     } catch (ParseException e) {
                         throw new JsonParseException(e);
                     }
@@ -348,7 +341,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
 
     /**
      * Gson TypeAdapter for java.util.Date type
-     * If the dateFormat is null, DateTimeFormatter will be used.
+     * If the dateFormat is null, ISO8601Utils will be used.
      */
     public static class DateTypeAdapter extends TypeAdapter<Date> {
 
@@ -373,7 +366,7 @@ public void write(JsonWriter out, Date date) throws IOException {
                 if (dateFormat != null) {
                     value = dateFormat.format(date);
                 } else {
-                    value = date.toInstant().atOffset(ZoneOffset.UTC).format(dtf);
+                    value = ISO8601Utils.format(date, true);
                 }
                 out.value(value);
             }
@@ -392,7 +385,7 @@ public Date read(JsonReader in) throws IOException {
                             if (dateFormat != null) {
                                 return dateFormat.parse(date);
                             }
-                            return sdf.parse(date);
+                            return ISO8601Utils.parse(date, new ParsePosition(0));
                         } catch (ParseException e) {
                             throw new JsonParseException(e);
                         }
diff --git a/samples/client/petstore/java/okhttp-gson-nullable-required/src/main/java/org/openapitools/client/JSON.java b/samples/client/petstore/java/okhttp-gson-nullable-required/src/main/java/org/openapitools/client/JSON.java
index 75faa7a82b3f8..cc08e8c32f432 100644
--- a/samples/client/petstore/java/okhttp-gson-nullable-required/src/main/java/org/openapitools/client/JSON.java
+++ b/samples/client/petstore/java/okhttp-gson-nullable-required/src/main/java/org/openapitools/client/JSON.java
@@ -13,11 +13,11 @@
 
 package org.openapitools.client;
 
-import com.fasterxml.jackson.databind.util.StdDateFormat;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonParseException;
 import com.google.gson.TypeAdapter;
+import com.google.gson.internal.bind.util.ISO8601Utils;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
 import com.google.gson.JsonElement;
@@ -31,16 +31,14 @@
 import java.lang.reflect.Type;
 import java.text.DateFormat;
 import java.text.ParseException;
+import java.text.ParsePosition;
 import java.time.LocalDate;
 import java.time.OffsetDateTime;
-import java.time.ZoneId;
-import java.time.ZoneOffset;
 import java.time.format.DateTimeFormatter;
 import java.util.Date;
 import java.util.Locale;
 import java.util.Map;
 import java.util.HashMap;
-import java.util.TimeZone;
 
 /*
  * A JSON utility class
@@ -57,11 +55,6 @@ public class JSON {
     private static LocalDateTypeAdapter localDateTypeAdapter = new LocalDateTypeAdapter();
     private static ByteArrayAdapter byteArrayAdapter = new ByteArrayAdapter();
 
-    private static final StdDateFormat sdf = new StdDateFormat()
-        .withTimeZone(TimeZone.getTimeZone(ZoneId.systemDefault()))
-        .withColonInTimeZone(true);
-    private static final DateTimeFormatter dtf = DateTimeFormatter.ISO_OFFSET_DATE_TIME;
-
     @SuppressWarnings("unchecked")
     public static GsonBuilder createGson() {
         GsonFireBuilder fireBuilder = new GsonFireBuilder()
@@ -340,7 +333,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
                         if (dateFormat != null) {
                             return new java.sql.Date(dateFormat.parse(date).getTime());
                         }
-                        return new java.sql.Date(sdf.parse(date).getTime());
+                        return new java.sql.Date(ISO8601Utils.parse(date, new ParsePosition(0)).getTime());
                     } catch (ParseException e) {
                         throw new JsonParseException(e);
                     }
@@ -350,7 +343,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
 
     /**
      * Gson TypeAdapter for java.util.Date type
-     * If the dateFormat is null, DateTimeFormatter will be used.
+     * If the dateFormat is null, ISO8601Utils will be used.
      */
     public static class DateTypeAdapter extends TypeAdapter<Date> {
 
@@ -375,7 +368,7 @@ public void write(JsonWriter out, Date date) throws IOException {
                 if (dateFormat != null) {
                     value = dateFormat.format(date);
                 } else {
-                    value = date.toInstant().atOffset(ZoneOffset.UTC).format(dtf);
+                    value = ISO8601Utils.format(date, true);
                 }
                 out.value(value);
             }
@@ -394,7 +387,7 @@ public Date read(JsonReader in) throws IOException {
                             if (dateFormat != null) {
                                 return dateFormat.parse(date);
                             }
-                            return sdf.parse(date);
+                            return ISO8601Utils.parse(date, new ParsePosition(0));
                         } catch (ParseException e) {
                             throw new JsonParseException(e);
                         }
diff --git a/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/JSON.java b/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/JSON.java
index 349f4ff81132a..6d80edba2a7bf 100644
--- a/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/JSON.java
+++ b/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/JSON.java
@@ -13,11 +13,11 @@
 
 package org.openapitools.client;
 
-import com.fasterxml.jackson.databind.util.StdDateFormat;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonParseException;
 import com.google.gson.TypeAdapter;
+import com.google.gson.internal.bind.util.ISO8601Utils;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
 import com.google.gson.JsonElement;
@@ -31,16 +31,14 @@
 import java.lang.reflect.Type;
 import java.text.DateFormat;
 import java.text.ParseException;
+import java.text.ParsePosition;
 import java.time.LocalDate;
 import java.time.OffsetDateTime;
-import java.time.ZoneId;
-import java.time.ZoneOffset;
 import java.time.format.DateTimeFormatter;
 import java.util.Date;
 import java.util.Locale;
 import java.util.Map;
 import java.util.HashMap;
-import java.util.TimeZone;
 
 /*
  * A JSON utility class
@@ -57,11 +55,6 @@ public class JSON {
     private static LocalDateTypeAdapter localDateTypeAdapter = new LocalDateTypeAdapter();
     private static ByteArrayAdapter byteArrayAdapter = new ByteArrayAdapter();
 
-    private static final StdDateFormat sdf = new StdDateFormat()
-        .withTimeZone(TimeZone.getTimeZone(ZoneId.systemDefault()))
-        .withColonInTimeZone(true);
-    private static final DateTimeFormatter dtf = DateTimeFormatter.ISO_OFFSET_DATE_TIME;
-
     @SuppressWarnings("unchecked")
     public static GsonBuilder createGson() {
         GsonFireBuilder fireBuilder = new GsonFireBuilder()
@@ -413,7 +406,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
                         if (dateFormat != null) {
                             return new java.sql.Date(dateFormat.parse(date).getTime());
                         }
-                        return new java.sql.Date(sdf.parse(date).getTime());
+                        return new java.sql.Date(ISO8601Utils.parse(date, new ParsePosition(0)).getTime());
                     } catch (ParseException e) {
                         throw new JsonParseException(e);
                     }
@@ -423,7 +416,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
 
     /**
      * Gson TypeAdapter for java.util.Date type
-     * If the dateFormat is null, DateTimeFormatter will be used.
+     * If the dateFormat is null, ISO8601Utils will be used.
      */
     public static class DateTypeAdapter extends TypeAdapter<Date> {
 
@@ -448,7 +441,7 @@ public void write(JsonWriter out, Date date) throws IOException {
                 if (dateFormat != null) {
                     value = dateFormat.format(date);
                 } else {
-                    value = date.toInstant().atOffset(ZoneOffset.UTC).format(dtf);
+                    value = ISO8601Utils.format(date, true);
                 }
                 out.value(value);
             }
@@ -467,7 +460,7 @@ public Date read(JsonReader in) throws IOException {
                             if (dateFormat != null) {
                                 return dateFormat.parse(date);
                             }
-                            return sdf.parse(date);
+                            return ISO8601Utils.parse(date, new ParsePosition(0));
                         } catch (ParseException e) {
                             throw new JsonParseException(e);
                         }
diff --git a/samples/client/petstore/java/okhttp-gson-swagger1/src/main/java/org/openapitools/client/JSON.java b/samples/client/petstore/java/okhttp-gson-swagger1/src/main/java/org/openapitools/client/JSON.java
index ad2d26cbfbb76..f993e935c7aa4 100644
--- a/samples/client/petstore/java/okhttp-gson-swagger1/src/main/java/org/openapitools/client/JSON.java
+++ b/samples/client/petstore/java/okhttp-gson-swagger1/src/main/java/org/openapitools/client/JSON.java
@@ -13,11 +13,11 @@
 
 package org.openapitools.client;
 
-import com.fasterxml.jackson.databind.util.StdDateFormat;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonParseException;
 import com.google.gson.TypeAdapter;
+import com.google.gson.internal.bind.util.ISO8601Utils;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
 import com.google.gson.JsonElement;
@@ -31,16 +31,14 @@
 import java.lang.reflect.Type;
 import java.text.DateFormat;
 import java.text.ParseException;
+import java.text.ParsePosition;
 import java.time.LocalDate;
 import java.time.OffsetDateTime;
-import java.time.ZoneId;
-import java.time.ZoneOffset;
 import java.time.format.DateTimeFormatter;
 import java.util.Date;
 import java.util.Locale;
 import java.util.Map;
 import java.util.HashMap;
-import java.util.TimeZone;
 
 /*
  * A JSON utility class
@@ -57,11 +55,6 @@ public class JSON {
     private static LocalDateTypeAdapter localDateTypeAdapter = new LocalDateTypeAdapter();
     private static ByteArrayAdapter byteArrayAdapter = new ByteArrayAdapter();
 
-    private static final StdDateFormat sdf = new StdDateFormat()
-        .withTimeZone(TimeZone.getTimeZone(ZoneId.systemDefault()))
-        .withColonInTimeZone(true);
-    private static final DateTimeFormatter dtf = DateTimeFormatter.ISO_OFFSET_DATE_TIME;
-
     @SuppressWarnings("unchecked")
     public static GsonBuilder createGson() {
         GsonFireBuilder fireBuilder = new GsonFireBuilder()
@@ -338,7 +331,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
                         if (dateFormat != null) {
                             return new java.sql.Date(dateFormat.parse(date).getTime());
                         }
-                        return new java.sql.Date(sdf.parse(date).getTime());
+                        return new java.sql.Date(ISO8601Utils.parse(date, new ParsePosition(0)).getTime());
                     } catch (ParseException e) {
                         throw new JsonParseException(e);
                     }
@@ -348,7 +341,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
 
     /**
      * Gson TypeAdapter for java.util.Date type
-     * If the dateFormat is null, DateTimeFormatter will be used.
+     * If the dateFormat is null, ISO8601Utils will be used.
      */
     public static class DateTypeAdapter extends TypeAdapter<Date> {
 
@@ -373,7 +366,7 @@ public void write(JsonWriter out, Date date) throws IOException {
                 if (dateFormat != null) {
                     value = dateFormat.format(date);
                 } else {
-                    value = date.toInstant().atOffset(ZoneOffset.UTC).format(dtf);
+                    value = ISO8601Utils.format(date, true);
                 }
                 out.value(value);
             }
@@ -392,7 +385,7 @@ public Date read(JsonReader in) throws IOException {
                             if (dateFormat != null) {
                                 return dateFormat.parse(date);
                             }
-                            return sdf.parse(date);
+                            return ISO8601Utils.parse(date, new ParsePosition(0));
                         } catch (ParseException e) {
                             throw new JsonParseException(e);
                         }
diff --git a/samples/client/petstore/java/okhttp-gson-swagger2/src/main/java/org/openapitools/client/JSON.java b/samples/client/petstore/java/okhttp-gson-swagger2/src/main/java/org/openapitools/client/JSON.java
index ad2d26cbfbb76..f993e935c7aa4 100644
--- a/samples/client/petstore/java/okhttp-gson-swagger2/src/main/java/org/openapitools/client/JSON.java
+++ b/samples/client/petstore/java/okhttp-gson-swagger2/src/main/java/org/openapitools/client/JSON.java
@@ -13,11 +13,11 @@
 
 package org.openapitools.client;
 
-import com.fasterxml.jackson.databind.util.StdDateFormat;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonParseException;
 import com.google.gson.TypeAdapter;
+import com.google.gson.internal.bind.util.ISO8601Utils;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
 import com.google.gson.JsonElement;
@@ -31,16 +31,14 @@
 import java.lang.reflect.Type;
 import java.text.DateFormat;
 import java.text.ParseException;
+import java.text.ParsePosition;
 import java.time.LocalDate;
 import java.time.OffsetDateTime;
-import java.time.ZoneId;
-import java.time.ZoneOffset;
 import java.time.format.DateTimeFormatter;
 import java.util.Date;
 import java.util.Locale;
 import java.util.Map;
 import java.util.HashMap;
-import java.util.TimeZone;
 
 /*
  * A JSON utility class
@@ -57,11 +55,6 @@ public class JSON {
     private static LocalDateTypeAdapter localDateTypeAdapter = new LocalDateTypeAdapter();
     private static ByteArrayAdapter byteArrayAdapter = new ByteArrayAdapter();
 
-    private static final StdDateFormat sdf = new StdDateFormat()
-        .withTimeZone(TimeZone.getTimeZone(ZoneId.systemDefault()))
-        .withColonInTimeZone(true);
-    private static final DateTimeFormatter dtf = DateTimeFormatter.ISO_OFFSET_DATE_TIME;
-
     @SuppressWarnings("unchecked")
     public static GsonBuilder createGson() {
         GsonFireBuilder fireBuilder = new GsonFireBuilder()
@@ -338,7 +331,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
                         if (dateFormat != null) {
                             return new java.sql.Date(dateFormat.parse(date).getTime());
                         }
-                        return new java.sql.Date(sdf.parse(date).getTime());
+                        return new java.sql.Date(ISO8601Utils.parse(date, new ParsePosition(0)).getTime());
                     } catch (ParseException e) {
                         throw new JsonParseException(e);
                     }
@@ -348,7 +341,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
 
     /**
      * Gson TypeAdapter for java.util.Date type
-     * If the dateFormat is null, DateTimeFormatter will be used.
+     * If the dateFormat is null, ISO8601Utils will be used.
      */
     public static class DateTypeAdapter extends TypeAdapter<Date> {
 
@@ -373,7 +366,7 @@ public void write(JsonWriter out, Date date) throws IOException {
                 if (dateFormat != null) {
                     value = dateFormat.format(date);
                 } else {
-                    value = date.toInstant().atOffset(ZoneOffset.UTC).format(dtf);
+                    value = ISO8601Utils.format(date, true);
                 }
                 out.value(value);
             }
@@ -392,7 +385,7 @@ public Date read(JsonReader in) throws IOException {
                             if (dateFormat != null) {
                                 return dateFormat.parse(date);
                             }
-                            return sdf.parse(date);
+                            return ISO8601Utils.parse(date, new ParsePosition(0));
                         } catch (ParseException e) {
                             throw new JsonParseException(e);
                         }
diff --git a/samples/client/petstore/java/okhttp-gson/pom.xml b/samples/client/petstore/java/okhttp-gson/pom.xml
index dbf329da8a707..5bd5c322feeea 100644
--- a/samples/client/petstore/java/okhttp-gson/pom.xml
+++ b/samples/client/petstore/java/okhttp-gson/pom.xml
@@ -305,11 +305,6 @@
             <artifactId>jackson-databind-nullable</artifactId>
             <version>${jackson-databind-nullable-version}</version>
         </dependency>
-        <dependency>
-            <groupId>com.fasterxml.jackson.core</groupId>
-            <artifactId>jackson-databind</artifactId>
-            <version>${jackson-databind-version}</version>
-        </dependency>
         <dependency>
             <groupId>javax.ws.rs</groupId>
             <artifactId>jsr311-api</artifactId>
@@ -350,7 +345,6 @@
         <gson-version>2.10.1</gson-version>
         <commons-lang3-version>3.13.0</commons-lang3-version>
         <jackson-databind-nullable-version>0.2.6</jackson-databind-nullable-version>
-        <jackson-databind-version>2.16.0</jackson-databind-version>
         <jakarta-annotation-version>1.3.5</jakarta-annotation-version>
         <junit-version>5.10.0</junit-version>
         <junit-platform-runner.version>1.10.0</junit-platform-runner.version>
diff --git a/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/JSON.java b/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/JSON.java
index db57f2dbba89b..d13cb5a17e5ae 100644
--- a/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/JSON.java
+++ b/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/JSON.java
@@ -13,11 +13,11 @@
 
 package org.openapitools.client;
 
-import com.fasterxml.jackson.databind.util.StdDateFormat;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonParseException;
 import com.google.gson.TypeAdapter;
+import com.google.gson.internal.bind.util.ISO8601Utils;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
 import com.google.gson.JsonElement;
@@ -31,16 +31,14 @@
 import java.lang.reflect.Type;
 import java.text.DateFormat;
 import java.text.ParseException;
+import java.text.ParsePosition;
 import java.time.LocalDate;
 import java.time.OffsetDateTime;
-import java.time.ZoneId;
-import java.time.ZoneOffset;
 import java.time.format.DateTimeFormatter;
 import java.util.Date;
 import java.util.Locale;
 import java.util.Map;
 import java.util.HashMap;
-import java.util.TimeZone;
 
 /*
  * A JSON utility class
@@ -57,11 +55,6 @@ public class JSON {
     private static LocalDateTypeAdapter localDateTypeAdapter = new LocalDateTypeAdapter();
     private static ByteArrayAdapter byteArrayAdapter = new ByteArrayAdapter();
 
-    private static final StdDateFormat sdf = new StdDateFormat()
-        .withTimeZone(TimeZone.getTimeZone(ZoneId.systemDefault()))
-        .withColonInTimeZone(true);
-    private static final DateTimeFormatter dtf = DateTimeFormatter.ISO_OFFSET_DATE_TIME;
-
     @SuppressWarnings("unchecked")
     public static GsonBuilder createGson() {
         GsonFireBuilder fireBuilder = new GsonFireBuilder()
@@ -562,7 +555,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
                         if (dateFormat != null) {
                             return new java.sql.Date(dateFormat.parse(date).getTime());
                         }
-                        return new java.sql.Date(sdf.parse(date).getTime());
+                        return new java.sql.Date(ISO8601Utils.parse(date, new ParsePosition(0)).getTime());
                     } catch (ParseException e) {
                         throw new JsonParseException(e);
                     }
@@ -572,7 +565,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
 
     /**
      * Gson TypeAdapter for java.util.Date type
-     * If the dateFormat is null, DateTimeFormatter will be used.
+     * If the dateFormat is null, ISO8601Utils will be used.
      */
     public static class DateTypeAdapter extends TypeAdapter<Date> {
 
@@ -597,7 +590,7 @@ public void write(JsonWriter out, Date date) throws IOException {
                 if (dateFormat != null) {
                     value = dateFormat.format(date);
                 } else {
-                    value = date.toInstant().atOffset(ZoneOffset.UTC).format(dtf);
+                    value = ISO8601Utils.format(date, true);
                 }
                 out.value(value);
             }
@@ -616,7 +609,7 @@ public Date read(JsonReader in) throws IOException {
                             if (dateFormat != null) {
                                 return dateFormat.parse(date);
                             }
-                            return sdf.parse(date);
+                            return ISO8601Utils.parse(date, new ParsePosition(0));
                         } catch (ParseException e) {
                             throw new JsonParseException(e);
                         }
diff --git a/samples/client/petstore/java/rest-assured-jackson/pom.xml b/samples/client/petstore/java/rest-assured-jackson/pom.xml
index 499b537d6e625..30f05119867b5 100644
--- a/samples/client/petstore/java/rest-assured-jackson/pom.xml
+++ b/samples/client/petstore/java/rest-assured-jackson/pom.xml
@@ -227,11 +227,6 @@
             <artifactId>rest-assured</artifactId>
             <version>${rest-assured.version}</version>
         </dependency>
-        <dependency>
-            <groupId>com.fasterxml.jackson.core</groupId>
-            <artifactId>jackson-databind</artifactId>
-            <version>${jackson-databind-version}</version>
-        </dependency>
         <!-- JSON processing: jackson -->
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
@@ -241,6 +236,10 @@
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-annotations</artifactId>
         </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+        </dependency>
         <dependency>
             <groupId>org.openapitools</groupId>
             <artifactId>jackson-databind-nullable</artifactId>
@@ -281,8 +280,8 @@
         <rest-assured.version>5.3.2</rest-assured.version>
         <gson-version>2.10.1</gson-version>
         <gson-fire-version>1.9.0</gson-fire-version>
-        <jackson-databind-version>2.15.2</jackson-databind-version>
         <jackson-version>2.15.2</jackson-version>
+        <jackson-databind-version>2.15.2</jackson-databind-version>
         <jackson-databind-nullable-version>0.2.6</jackson-databind-nullable-version>
         <jakarta-annotation-version>1.3.5</jakarta-annotation-version>
         <beanvalidation-version>3.0.2</beanvalidation-version>
diff --git a/samples/client/petstore/java/rest-assured/src/main/java/org/openapitools/client/JSON.java b/samples/client/petstore/java/rest-assured/src/main/java/org/openapitools/client/JSON.java
index 5f2e9f70d6748..edcc9eed5b955 100644
--- a/samples/client/petstore/java/rest-assured/src/main/java/org/openapitools/client/JSON.java
+++ b/samples/client/petstore/java/rest-assured/src/main/java/org/openapitools/client/JSON.java
@@ -13,11 +13,11 @@
 
 package org.openapitools.client;
 
-import com.fasterxml.jackson.databind.util.StdDateFormat;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonParseException;
 import com.google.gson.TypeAdapter;
+import com.google.gson.internal.bind.util.ISO8601Utils;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
 import com.google.gson.JsonElement;
@@ -35,14 +35,11 @@
 import java.text.ParsePosition;
 import java.time.LocalDate;
 import java.time.OffsetDateTime;
-import java.time.ZoneOffset;
-import java.time.ZoneId;
 import java.time.format.DateTimeFormatter;
 import java.util.Date;
 import java.util.Locale;
 import java.util.Map;
 import java.util.HashMap;
-import java.util.TimeZone;
 
 public class JSON {
     private Gson gson;
@@ -53,11 +50,6 @@ public class JSON {
     private LocalDateTypeAdapter localDateTypeAdapter = new LocalDateTypeAdapter();
     private ByteArrayAdapter byteArrayAdapter = new ByteArrayAdapter();
 
-    private static final StdDateFormat sdf = new StdDateFormat()
-        .withTimeZone(TimeZone.getTimeZone(ZoneId.systemDefault()))
-        .withColonInTimeZone(true);
-    private static final DateTimeFormatter dtf = DateTimeFormatter.ISO_OFFSET_DATE_TIME;
-
     @SuppressWarnings("unchecked")
     public static GsonBuilder createGson() {
         GsonFireBuilder fireBuilder = new GsonFireBuilder()
@@ -380,7 +372,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
                         if (dateFormat != null) {
                             return new java.sql.Date(dateFormat.parse(date).getTime());
                         }
-                        return new java.sql.Date(sdf.parse(date).getTime());
+                        return new java.sql.Date(ISO8601Utils.parse(date, new ParsePosition(0)).getTime());
                     } catch (ParseException e) {
                         throw new JsonParseException(e);
                     }
@@ -390,7 +382,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
 
     /**
      * Gson TypeAdapter for java.util.Date type
-     * If the dateFormat is null, DateTimeFormatter will be used.
+     * If the dateFormat is null, ISO8601Utils will be used.
      */
     public static class DateTypeAdapter extends TypeAdapter<Date> {
 
@@ -415,7 +407,7 @@ public void write(JsonWriter out, Date date) throws IOException {
                 if (dateFormat != null) {
                     value = dateFormat.format(date);
                 } else {
-                    value = date.toInstant().atOffset(ZoneOffset.UTC).format(dtf);
+                    value = ISO8601Utils.format(date, true);
                 }
                 out.value(value);
             }
@@ -434,7 +426,7 @@ public Date read(JsonReader in) throws IOException {
                             if (dateFormat != null) {
                                 return dateFormat.parse(date);
                             }
-                            return sdf.parse(date);
+                            return ISO8601Utils.parse(date, new ParsePosition(0));
                         } catch (ParseException e) {
                             throw new JsonParseException(e);
                         }
diff --git a/samples/client/petstore/java/retrofit2-play26/pom.xml b/samples/client/petstore/java/retrofit2-play26/pom.xml
index 25ad911845aad..fe70f28501bd0 100644
--- a/samples/client/petstore/java/retrofit2-play26/pom.xml
+++ b/samples/client/petstore/java/retrofit2-play26/pom.xml
@@ -204,11 +204,6 @@
             <artifactId>swagger-annotations</artifactId>
             <version>${swagger-annotations-version}</version>
         </dependency>
-        <dependency>
-            <groupId>com.fasterxml.jackson.core</groupId>
-            <artifactId>jackson-databind</artifactId>
-            <version>${jackson-databind-version}</version>
-        </dependency>
         <!-- @Nullable annotation -->
         <dependency>
             <groupId>com.google.code.findbugs</groupId>
@@ -252,6 +247,11 @@
                 <artifactId>jackson-annotations</artifactId>
                 <version>${jackson-version}</version>
             </dependency>
+            <dependency>
+                <groupId>com.fasterxml.jackson.core</groupId>
+                <artifactId>jackson-databind</artifactId>
+                <version>${jackson-databind-version}</version>
+            </dependency>
             <dependency>
                 <groupId>org.openapitools</groupId>
                 <artifactId>jackson-databind-nullable</artifactId>
@@ -297,8 +297,8 @@
         <maven.compiler.source>${java.version}</maven.compiler.source>
         <maven.compiler.target>${java.version}</maven.compiler.target>
         <swagger-annotations-version>1.6.3</swagger-annotations-version>
-        <jackson-databind-version>2.15.2</jackson-databind-version>
         <jackson-version>2.15.2</jackson-version>
+        <jackson-databind-version>2.15.2</jackson-databind-version>
         <jackson-databind-nullable-version>0.2.6</jackson-databind-nullable-version>
         <javax.ws.rs-api-version>2.1.1</javax.ws.rs-api-version>
         <play-version>2.6.7</play-version>
diff --git a/samples/client/petstore/java/retrofit2/pom.xml b/samples/client/petstore/java/retrofit2/pom.xml
index 619349f68783c..27a703dff5653 100644
--- a/samples/client/petstore/java/retrofit2/pom.xml
+++ b/samples/client/petstore/java/retrofit2/pom.xml
@@ -204,11 +204,6 @@
             <artifactId>swagger-annotations</artifactId>
             <version>${swagger-annotations-version}</version>
         </dependency>
-        <dependency>
-            <groupId>com.fasterxml.jackson.core</groupId>
-            <artifactId>jackson-databind</artifactId>
-            <version>${jackson-databind-version}</version>
-        </dependency>
         <!-- @Nullable annotation -->
         <dependency>
             <groupId>com.google.code.findbugs</groupId>
@@ -267,7 +262,6 @@
         <maven.compiler.target>${java.version}</maven.compiler.target>
         <gson-fire-version>1.9.0</gson-fire-version>
         <swagger-annotations-version>1.6.3</swagger-annotations-version>
-        <jackson-databind-version>2.15.2</jackson-databind-version>
         <retrofit-version>2.5.0</retrofit-version>
         <jakarta-annotation-version>1.3.5</jakarta-annotation-version>
         <oltu-version>1.0.1</oltu-version>
diff --git a/samples/client/petstore/java/retrofit2/src/main/java/org/openapitools/client/JSON.java b/samples/client/petstore/java/retrofit2/src/main/java/org/openapitools/client/JSON.java
index bce9a553a7d9d..65ad4ef6f55d1 100644
--- a/samples/client/petstore/java/retrofit2/src/main/java/org/openapitools/client/JSON.java
+++ b/samples/client/petstore/java/retrofit2/src/main/java/org/openapitools/client/JSON.java
@@ -13,11 +13,11 @@
 
 package org.openapitools.client;
 
-import com.fasterxml.jackson.databind.util.StdDateFormat;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonParseException;
 import com.google.gson.TypeAdapter;
+import com.google.gson.internal.bind.util.ISO8601Utils;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
 import com.google.gson.JsonElement;
@@ -34,14 +34,11 @@
 import java.text.ParsePosition;
 import java.time.LocalDate;
 import java.time.OffsetDateTime;
-import java.time.ZoneOffset;
-import java.time.ZoneId;
 import java.time.format.DateTimeFormatter;
 import java.util.Date;
 import java.util.Locale;
 import java.util.Map;
 import java.util.HashMap;
-import java.util.TimeZone;
 
 public class JSON {
     private Gson gson;
@@ -50,11 +47,6 @@ public class JSON {
     private OffsetDateTimeTypeAdapter offsetDateTimeTypeAdapter = new OffsetDateTimeTypeAdapter();
     private LocalDateTypeAdapter localDateTypeAdapter = new LocalDateTypeAdapter();
 
-    private static final StdDateFormat sdf = new StdDateFormat()
-        .withTimeZone(TimeZone.getTimeZone(ZoneId.systemDefault()))
-        .withColonInTimeZone(true);
-    private static final DateTimeFormatter dtf = DateTimeFormatter.ISO_OFFSET_DATE_TIME;
-
     public static GsonBuilder createGson() {
         GsonFireBuilder fireBuilder = new GsonFireBuilder()
           .registerTypeSelector(Animal.class, new TypeSelector() {
@@ -293,7 +285,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
                         if (dateFormat != null) {
                             return new java.sql.Date(dateFormat.parse(date).getTime());
                         }
-                        return new java.sql.Date(sdf.parse(date).getTime());
+                        return new java.sql.Date(ISO8601Utils.parse(date, new ParsePosition(0)).getTime());
                     } catch (ParseException e) {
                         throw new JsonParseException(e);
                     }
@@ -303,7 +295,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
 
     /**
      * Gson TypeAdapter for java.util.Date type
-     * If the dateFormat is null, DateTimeFormatter will be used.
+     * If the dateFormat is null, ISO8601Utils will be used.
      */
     public static class DateTypeAdapter extends TypeAdapter<Date> {
 
@@ -329,7 +321,7 @@ public void write(JsonWriter out, Date date) throws IOException {
                 if (dateFormat != null) {
                     value = dateFormat.format(date);
                 } else {
-                    value = date.toInstant().atOffset(ZoneOffset.UTC).format(dtf);
+                    value = ISO8601Utils.format(date, true);
                 }
                 out.value(value);
             }
@@ -348,7 +340,7 @@ public Date read(JsonReader in) throws IOException {
                             if (dateFormat != null) {
                                 return dateFormat.parse(date);
                             }
-                            return sdf.parse(date);
+                            return ISO8601Utils.parse(date, new ParsePosition(0));
                         } catch (ParseException e) {
                             throw new JsonParseException(e);
                         }
diff --git a/samples/client/petstore/java/retrofit2rx2/pom.xml b/samples/client/petstore/java/retrofit2rx2/pom.xml
index 62305514590e5..283c5647bd8b2 100644
--- a/samples/client/petstore/java/retrofit2rx2/pom.xml
+++ b/samples/client/petstore/java/retrofit2rx2/pom.xml
@@ -204,11 +204,6 @@
             <artifactId>swagger-annotations</artifactId>
             <version>${swagger-annotations-version}</version>
         </dependency>
-        <dependency>
-            <groupId>com.fasterxml.jackson.core</groupId>
-            <artifactId>jackson-databind</artifactId>
-            <version>${jackson-databind-version}</version>
-        </dependency>
         <!-- @Nullable annotation -->
         <dependency>
             <groupId>com.google.code.findbugs</groupId>
@@ -277,7 +272,6 @@
         <maven.compiler.target>${java.version}</maven.compiler.target>
         <gson-fire-version>1.9.0</gson-fire-version>
         <swagger-annotations-version>1.6.3</swagger-annotations-version>
-        <jackson-databind-version>2.15.2</jackson-databind-version>
         <retrofit-version>2.5.0</retrofit-version>
         <rxjava-version>2.1.1</rxjava-version>
         <jakarta-annotation-version>1.3.5</jakarta-annotation-version>
diff --git a/samples/client/petstore/java/retrofit2rx2/src/main/java/org/openapitools/client/JSON.java b/samples/client/petstore/java/retrofit2rx2/src/main/java/org/openapitools/client/JSON.java
index bce9a553a7d9d..65ad4ef6f55d1 100644
--- a/samples/client/petstore/java/retrofit2rx2/src/main/java/org/openapitools/client/JSON.java
+++ b/samples/client/petstore/java/retrofit2rx2/src/main/java/org/openapitools/client/JSON.java
@@ -13,11 +13,11 @@
 
 package org.openapitools.client;
 
-import com.fasterxml.jackson.databind.util.StdDateFormat;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonParseException;
 import com.google.gson.TypeAdapter;
+import com.google.gson.internal.bind.util.ISO8601Utils;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
 import com.google.gson.JsonElement;
@@ -34,14 +34,11 @@
 import java.text.ParsePosition;
 import java.time.LocalDate;
 import java.time.OffsetDateTime;
-import java.time.ZoneOffset;
-import java.time.ZoneId;
 import java.time.format.DateTimeFormatter;
 import java.util.Date;
 import java.util.Locale;
 import java.util.Map;
 import java.util.HashMap;
-import java.util.TimeZone;
 
 public class JSON {
     private Gson gson;
@@ -50,11 +47,6 @@ public class JSON {
     private OffsetDateTimeTypeAdapter offsetDateTimeTypeAdapter = new OffsetDateTimeTypeAdapter();
     private LocalDateTypeAdapter localDateTypeAdapter = new LocalDateTypeAdapter();
 
-    private static final StdDateFormat sdf = new StdDateFormat()
-        .withTimeZone(TimeZone.getTimeZone(ZoneId.systemDefault()))
-        .withColonInTimeZone(true);
-    private static final DateTimeFormatter dtf = DateTimeFormatter.ISO_OFFSET_DATE_TIME;
-
     public static GsonBuilder createGson() {
         GsonFireBuilder fireBuilder = new GsonFireBuilder()
           .registerTypeSelector(Animal.class, new TypeSelector() {
@@ -293,7 +285,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
                         if (dateFormat != null) {
                             return new java.sql.Date(dateFormat.parse(date).getTime());
                         }
-                        return new java.sql.Date(sdf.parse(date).getTime());
+                        return new java.sql.Date(ISO8601Utils.parse(date, new ParsePosition(0)).getTime());
                     } catch (ParseException e) {
                         throw new JsonParseException(e);
                     }
@@ -303,7 +295,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
 
     /**
      * Gson TypeAdapter for java.util.Date type
-     * If the dateFormat is null, DateTimeFormatter will be used.
+     * If the dateFormat is null, ISO8601Utils will be used.
      */
     public static class DateTypeAdapter extends TypeAdapter<Date> {
 
@@ -329,7 +321,7 @@ public void write(JsonWriter out, Date date) throws IOException {
                 if (dateFormat != null) {
                     value = dateFormat.format(date);
                 } else {
-                    value = date.toInstant().atOffset(ZoneOffset.UTC).format(dtf);
+                    value = ISO8601Utils.format(date, true);
                 }
                 out.value(value);
             }
@@ -348,7 +340,7 @@ public Date read(JsonReader in) throws IOException {
                             if (dateFormat != null) {
                                 return dateFormat.parse(date);
                             }
-                            return sdf.parse(date);
+                            return ISO8601Utils.parse(date, new ParsePosition(0));
                         } catch (ParseException e) {
                             throw new JsonParseException(e);
                         }
diff --git a/samples/client/petstore/java/retrofit2rx3/pom.xml b/samples/client/petstore/java/retrofit2rx3/pom.xml
index 4abc9a52d93da..5546912ccb141 100644
--- a/samples/client/petstore/java/retrofit2rx3/pom.xml
+++ b/samples/client/petstore/java/retrofit2rx3/pom.xml
@@ -204,11 +204,6 @@
             <artifactId>swagger-annotations</artifactId>
             <version>${swagger-annotations-version}</version>
         </dependency>
-        <dependency>
-            <groupId>com.fasterxml.jackson.core</groupId>
-            <artifactId>jackson-databind</artifactId>
-            <version>${jackson-databind-version}</version>
-        </dependency>
         <!-- @Nullable annotation -->
         <dependency>
             <groupId>com.google.code.findbugs</groupId>
@@ -277,7 +272,6 @@
         <maven.compiler.target>${java.version}</maven.compiler.target>
         <gson-fire-version>1.9.0</gson-fire-version>
         <swagger-annotations-version>1.6.3</swagger-annotations-version>
-        <jackson-databind-version>2.15.2</jackson-databind-version>
         <retrofit-version>2.5.0</retrofit-version>
         <rxjava-version>3.0.4</rxjava-version>
         <jakarta-annotation-version>1.3.5</jakarta-annotation-version>
diff --git a/samples/client/petstore/java/retrofit2rx3/src/main/java/org/openapitools/client/JSON.java b/samples/client/petstore/java/retrofit2rx3/src/main/java/org/openapitools/client/JSON.java
index bce9a553a7d9d..65ad4ef6f55d1 100644
--- a/samples/client/petstore/java/retrofit2rx3/src/main/java/org/openapitools/client/JSON.java
+++ b/samples/client/petstore/java/retrofit2rx3/src/main/java/org/openapitools/client/JSON.java
@@ -13,11 +13,11 @@
 
 package org.openapitools.client;
 
-import com.fasterxml.jackson.databind.util.StdDateFormat;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.JsonParseException;
 import com.google.gson.TypeAdapter;
+import com.google.gson.internal.bind.util.ISO8601Utils;
 import com.google.gson.stream.JsonReader;
 import com.google.gson.stream.JsonWriter;
 import com.google.gson.JsonElement;
@@ -34,14 +34,11 @@
 import java.text.ParsePosition;
 import java.time.LocalDate;
 import java.time.OffsetDateTime;
-import java.time.ZoneOffset;
-import java.time.ZoneId;
 import java.time.format.DateTimeFormatter;
 import java.util.Date;
 import java.util.Locale;
 import java.util.Map;
 import java.util.HashMap;
-import java.util.TimeZone;
 
 public class JSON {
     private Gson gson;
@@ -50,11 +47,6 @@ public class JSON {
     private OffsetDateTimeTypeAdapter offsetDateTimeTypeAdapter = new OffsetDateTimeTypeAdapter();
     private LocalDateTypeAdapter localDateTypeAdapter = new LocalDateTypeAdapter();
 
-    private static final StdDateFormat sdf = new StdDateFormat()
-        .withTimeZone(TimeZone.getTimeZone(ZoneId.systemDefault()))
-        .withColonInTimeZone(true);
-    private static final DateTimeFormatter dtf = DateTimeFormatter.ISO_OFFSET_DATE_TIME;
-
     public static GsonBuilder createGson() {
         GsonFireBuilder fireBuilder = new GsonFireBuilder()
           .registerTypeSelector(Animal.class, new TypeSelector() {
@@ -293,7 +285,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
                         if (dateFormat != null) {
                             return new java.sql.Date(dateFormat.parse(date).getTime());
                         }
-                        return new java.sql.Date(sdf.parse(date).getTime());
+                        return new java.sql.Date(ISO8601Utils.parse(date, new ParsePosition(0)).getTime());
                     } catch (ParseException e) {
                         throw new JsonParseException(e);
                     }
@@ -303,7 +295,7 @@ public java.sql.Date read(JsonReader in) throws IOException {
 
     /**
      * Gson TypeAdapter for java.util.Date type
-     * If the dateFormat is null, DateTimeFormatter will be used.
+     * If the dateFormat is null, ISO8601Utils will be used.
      */
     public static class DateTypeAdapter extends TypeAdapter<Date> {
 
@@ -329,7 +321,7 @@ public void write(JsonWriter out, Date date) throws IOException {
                 if (dateFormat != null) {
                     value = dateFormat.format(date);
                 } else {
-                    value = date.toInstant().atOffset(ZoneOffset.UTC).format(dtf);
+                    value = ISO8601Utils.format(date, true);
                 }
                 out.value(value);
             }
@@ -348,7 +340,7 @@ public Date read(JsonReader in) throws IOException {
                             if (dateFormat != null) {
                                 return dateFormat.parse(date);
                             }
-                            return sdf.parse(date);
+                            return ISO8601Utils.parse(date, new ParsePosition(0));
                         } catch (ParseException e) {
                             throw new JsonParseException(e);
                         }