apache/seatunnel · error · UnsupportedOperationException

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

Error message

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

What it means

The typeDefine-less convertDecimal(Object) handles Number and String values only; anything else causes UnsupportedOperationException naming the value's class. It indicates the DECIMAL conversion has no rule for that runtime type.

Source

Thrown at seatunnel-api/src/main/java/org/apache/seatunnel/api/table/converter/BasicDataConverter.java:847

    default BigDecimal convertDecimal(T typeDefine, Number value) {
        return convertDecimal(value);
    }

    default BigDecimal convertDecimal(T typeDefine, String value) {
        return convertDecimal(value);
    }

    default BigDecimal convertDecimal(Object value) throws UnsupportedOperationException {
        if (value instanceof BigDecimal) {
            return (BigDecimal) value;
        }
        if (value instanceof Number) {
            return convertDecimal((Number) value);
        }
        if (value instanceof String) {
            return convertDecimal((String) value);
        }
        throw new UnsupportedOperationException(
                "Unsupported convert " + value.getClass() + " to BigDecimal");
    }

    default BigDecimal convertDecimal(Number value) {
        return new BigDecimal(value.doubleValue());
    }

    default BigDecimal convertDecimal(String value) {
        return new BigDecimal(value);
    }

    default double convertDouble(T typeDefine, Object value) throws UnsupportedOperationException {
        if (value instanceof Double) {
            return (double) value;
        }
        if (value instanceof Number) {
            return convertDouble(typeDefine, (Number) value);
        }

View on GitHub (pinned to cf67b549a7)

Solutions

1. Pre-convert to BigDecimal, another Number, or a plain numeric String before calling convert
2. Add a custom converter branch for the class named in the message
3. Correct the source mapping so the field deserializes to a numeric type

Example fix

// before
converter.convert(rawDecimalBuffer); // throws
// after
BigDecimal bd = new BigDecimal(new String(rawDecimalBuffer));
converter.convert(bd);

if (!(v instanceof Number) && !(v instanceof String)) {
    throw new IllegalStateException("Unsupported decimal class: " + v.getClass());
}

boolean isConvertibleToDecimal(Object v) {
    return v instanceof Number || v instanceof String;
}

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

When it happens

Trigger: Calling convert()/convertDecimal(Object) with unhandled classes such as byte[], char[], or custom decimal wrappers for a DECIMAL column.

Common situations: Custom connectors passing raw binary decimal buffers; upstream version changes altering deserialization classes; mistakenly passing structured objects instead of scalars.

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

• Unsupported convert ${value.getClass()} to BigDecimal, typeD
• Unsupported convert ${value.getClass()} to LocalTime, typeDe
• Unsupported convert ${value.getClass()} to LocalTime
• Unsupported convert ${value.getClass()} to LocalDate, typeDe
• Unsupported convert ${value.getClass()} to LocalDate

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/e8ecfbe49a543a56. Report an issue: GitHub.