JodaTime Classes

DateTime

  private static class DateTimeTypeConverter
      implements JsonSerializer<DateTime>, JsonDeserializer<DateTime> {
    @Override
    public JsonElement serialize(DateTime src, Type srcType, JsonSerializationContext context) {
      return new JsonPrimitive(src.toString());
    }

    @Override
    public DateTime deserialize(JsonElement json, Type type, JsonDeserializationContext context)
        throws JsonParseException {
      try {
        return new DateTime(json.getAsString());
      } catch (IllegalArgumentException e) {
        // May be it came in formatted as a java.util.Date, so try that
        Date date = context.deserialize(json, Date.class);
        return new DateTime(date);
      }
    }
  }

Instant

  private static class InstantTypeConverter
      implements JsonSerializer<Instant>, JsonDeserializer<Instant> {
    @Override
    public JsonElement serialize(Instant src, Type srcType, JsonSerializationContext context) {
      return new JsonPrimitive(src.getMillis());
    }

    @Override
    public Instant deserialize(JsonElement json, Type type, JsonDeserializationContext context)
    throws JsonParseException {
      return new Instant(json.getAsLong());
    }
  }