@Override
        public void serializeWithType(final Map.Entry entry, final JsonGenerator jsonGenerator,
                                      final SerializerProvider serializerProvider, final TypeSerializer typeSerializer) throws IOException {
            typeSerializer.writeTypePrefixForObject(entry, jsonGenerator);
            ser(entry, jsonGenerator, serializerProvider);
            typeSerializer.writeTypeSuffixForObject(entry, jsonGenerator);
        }
GraphSON serializers for classes in {@code java.util.*} for the version 2.0 of GraphSON.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/structure/io/graphson/JavaUtilSerializersV2.java