@Override
        public void serialize(final Map.Entry entry, final JsonGenerator jsonGenerator, final SerializerProvider serializerProvider)
                throws IOException {
            ser(entry, jsonGenerator, serializerProvider, null);
        }
GraphSON serializers for classes in {@code java.util.*}.
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/structure/io/graphson/JavaUtilSerializersV1.java