apache/seatunnel · error · UnsupportedOperationException

Unsupported convert ${value.getClass()} to LocalDate

Error message

Unsupported convert ${value.getClass()} to LocalDate

What it means

The typeDefine-less convertLocalDate(Object) handles String, Number and temporal values; an unhandled class causes UnsupportedOperationException naming the value's class. The converter throws because it cannot interpret the value as a LocalDate.

Source

Thrown at seatunnel-api/src/main/java/org/apache/seatunnel/api/table/converter/BasicDataConverter.java:788

        if (value instanceof LocalDate) {
            return (LocalDate) value;
        }
        if (value instanceof Date) {
            return convertLocalDate((Date) value);
        }
        if (value instanceof LocalDateTime) {
            return ((LocalDateTime) value).toLocalDate();
        }
        if (value instanceof java.sql.Date) {
            return ((java.sql.Date) value).toLocalDate();
        }
        if (value instanceof String) {
            return convertLocalDate((String) value);
        }
        if (value instanceof Number) {
            return convertLocalDate((Number) value);
        }
        throw new UnsupportedOperationException(
                "Unsupported convert " + value.getClass() + " to LocalDate");
    }

    default LocalDate convertLocalDate(Date value) {
        return value.toInstant().atZone(ZoneId.systemDefault()).toLocalDate();
    }

    default LocalDate convertLocalDate(String value) {
        return LocalDate.parse(value);
    }

    default LocalDate convertLocalDate(Number value) {
        if (value.longValue() < 999999999) {
            return LocalDateTime.ofEpochSecond(
                            value.longValue(),
                            0,
                            ZoneId.systemDefault().getRules().getOffset(LocalDateTime.now()))
                    .toLocalDate();

View on GitHub (pinned to cf67b549a7)

Solutions

  1. Pre-convert the value to LocalDate, ISO-8601 String, or epoch Number before calling convert
  2. Inspect the named class and add a custom converter branch if the source always emits it
  3. Fix the source schema/mapping so the field type aligns with the DATE column

Example fix

// before
converter.convert(calendarObj); // throws
// after
LocalDate d = ((java.util.Calendar) calendarObj).toInstant().atZone(ZoneId.systemDefault()).toLocalDate();
converter.convert(d);
Defensive patterns

Strategy: type-guard

Validate before calling

if (!(v instanceof Number) && !(v instanceof String) && !(v instanceof java.time.temporal.TemporalAccessor) && !(v instanceof java.util.Date)) {
    throw new IllegalStateException("Unsupported date class: " + v.getClass());
}

Type guard

boolean isConvertibleToDate(Object v) {
    return v instanceof Number || v instanceof String
        || v instanceof java.time.temporal.TemporalAccessor
        || v instanceof java.util.Date;
}

Try / catch

try {
    converter.convert(value);
} catch (UnsupportedOperationException e) {
    LOG.warn("Date convert failed, class={}", value.getClass(), e);
    value = normalizeToDate(value);
}

Prevention

When it happens

Trigger: Calling convert()/convertLocalDate(Object) with e.g. java.util.Calendar, char[], or an application object for a DATE column where no instanceof branch matches.

Common situations: Custom transforms forwarding untyped Objects; upstream format change (e.g. Avro date logical type now deserialized as a custom class); accidentally passing a timestamp object where the target expects only a date.

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/fa52a74d0b3efc8b. Report an issue: GitHub.