The empty string is converted to null

Hi there, When I query the empty string, I find that the value I get is null, So I debug the source code to find the empty string is converted to null. why it is designed this way? Below is the source code section.

    @Nullable
    private Object toValue(@Nullable final String strValue, final @Nonnull FluxColumn column) {

        Arguments.checkNotNull(column, "column");

        // Default value
        if (strValue == null || strValue.isEmpty()) {
            String defaultValue = column.getDefaultValue();
            if (defaultValue == null || defaultValue.isEmpty()) {
                return null;
            }

            return toValue(defaultValue, column);
        }

        String dataType = column.getDataType();
        switch (dataType) {
            case "boolean":
                return Boolean.valueOf(strValue);
            case "unsignedLong":
                return Long.parseUnsignedLong(strValue);
            case "long":
                return Long.parseLong(strValue);
            case "double":
                switch (strValue) {
                    case "+Inf":
                        return Double.POSITIVE_INFINITY;
                    case "-Inf":
                        return Double.NEGATIVE_INFINITY;
                    default:
                        return Double.parseDouble(strValue);
                }
            case "base64Binary":
                return Base64.getDecoder().decode(strValue);
            case "dateTime:RFC3339":
            case "dateTime:RFC3339Nano":
                return Instant.parse(strValue);
            case "duration":
                return Duration.ofNanos(Long.parseUnsignedLong(strValue));
            default:
            case "string":
                return strValue;
        }
    }

influxdata / influxdb-client-java

The empty string is converted to null #644