apache/seatunnel · error · UnsupportedOperationException

reconvert not support

Error message

reconvert not support

What it means

DataConverter.reconvert(T typeDefine, Object value) is a default method that converters may override to convert data back from SeaTunnel internal types to external/source types. The default implementation does nothing but throw this UnsupportedOperationException, meaning the concrete converter does not support reverse conversion.

Source

Thrown at seatunnel-api/src/main/java/org/apache/seatunnel/api/table/converter/DataConverter.java:103

        for (int i = 0; i < fields.length; i++) {
            fields[i] = convert(hasTypeDefine ? typeDefine[i] : null, columnDefine[i], fields[i]);
        }
        return fields;
    }

    default Object reconvert(T typeDefine, Column columnDefine, Object value) {
        return reconvert(typeDefine, value);
    }

    /**
     * Convert object to an external system's data type.
     *
     * @param typeDefine
     * @param value
     * @return
     */
    default Object reconvert(T typeDefine, Object value) {
        throw new UnsupportedOperationException("reconvert not support");
    }

    default Object reconvert(Column columnDefine, Object value) {
        return reconvert(columnDefine.getDataType(), value);
    }

    /**
     * Convert {@link SeaTunnelDataType#getTypeClass()} to an external system's data type.
     *
     * @param typeDefine
     * @param value
     * @return
     */
    default Object reconvert(SeaTunnelDataType typeDefine, Object value) {
        throw new UnsupportedOperationException("reconvert not support");
    }
}

View on GitHub (pinned to cf67b549a7)

Solutions

1. Implement/override reconvert(T, Object) in the converter if reverse conversion is required
2. Avoid the reconvert code path for this converter and convert externally
3. Switch to a converter implementation that supports reconvert

Example fix

// before
// default: throws
default Object reconvert(T typeDefine, Object value) { throw new UnsupportedOperationException("reconvert not support"); }
// after
@Override
public Object reconvert(MyTypeDefine typeDefine, Object value) {
    return externalFormat((SeaTunnelRow) value, typeDefine);
}

// probe once at startup whether reconvert is supported
try {
    converter.reconvert(typeDefine, sampleValue);
    reconvertSupported = true;
} catch (UnsupportedOperationException e) {
    reconvertSupported = false;
}

try {
    Object nativeValue = converter.reconvert(typeDefine, value);
} catch (UnsupportedOperationException e) {
    // fall back to external reverse conversion or skip
    nativeValue = fallbackReconvert(value);
}

When it happens

Trigger: Calling reconvert(typeDefine, value) (including via the Column overload which delegates here) on a converter that has not overridden the method.

Common situations: Using a write-back or echo feature that assumes bidirectional conversion with a converter that only implements forward conversion.

Related errors

• Unsupported convert ${value.getClass()} to Float, typeDefine
• Unsupported convert ${value.getClass()} to Float
• Unsupported convert ${value.getClass()} to Long, typeDefine:
• Unsupported convert ${value.getClass()} to Long
• Unsupported convert ${value.getClass()} to Integer, typeDefi

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/3742f40b4a8e3d2a. Report an issue: GitHub.