apache/seatunnel · error · UnsupportedOperationException

Unsupported convert to Double

Error message

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

What it means

The typeDefine-less convertDouble(Object) accepts Number and String; an unhandled class causes UnsupportedOperationException naming the value's class. It signals there is no double conversion rule for the supplied runtime type.

Solutions

1. Pre-convert the value to a Number or numeric String before calling convert
2. Add a custom converter branch for the offending class
3. Correct the source mapping so the field deserializes as a numeric type

Example fix

// before
converter.convert(flag); // Boolean, throws
// after
double d = ((Boolean) flag) ? 1.0 : 0.0;
converter.convert(d);

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

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

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

When it happens

Trigger: Calling convert()/convertDouble(Object) with classes like byte[], char[], Boolean, or domain objects for a DOUBLE column.

Common situations: Custom transforms forwarding raw Objects; upstream format changes altering the deserialized class; mistakenly passing structured or boolean values where scalars are expected.

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 to Double, typeDefine
• COMMON-17
• Unsupported convert to BigDecimal, typeDefine
• Unsupported convert to BigDecimal
• Unsupported convert to Boolean, typeDefine

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/765fe9b60a26b5be. Report an issue: GitHub.

Appendix: source

Thrown at seatunnel-api/src/main/java/org/apache/seatunnel/api/table/converter/BasicDataConverter.java:894

    default double convertDouble(T typeDefine, Number value) {
        return convertDouble(value);
    }

    default double convertDouble(T typeDefine, String value) {
        return convertDouble(value);
    }

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

    default double convertDouble(Number value) {
        return value.doubleValue();
    }

    default double convertDouble(String value) {
        return Double.parseDouble(value);
    }

    default float convertFloat(T typeDefine, Object value) throws UnsupportedOperationException {
        if (value instanceof Float) {
            return (float) value;
        }
        if (value instanceof Number) {
            return convertFloat(typeDefine, (Number) value);
        }

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