apache/seatunnel · error · UnsupportedOperationException

MAP type requires key and value types

Error message

MAP type requires key and value types

What it means

When converting a MAP type to a Hive map type, both the key type and value type from MapType.getKeyType()/getValueType() must be non-null. A null key or value type cannot be rendered as `map<k,v>` so the converter throws UnsupportedOperationException.

Source

Thrown at seatunnel-connectors-v2/connector-hive/src/main/java/org/apache/seatunnel/connectors/seatunnel/hive/utils/HiveTypeConvertor.java:143

                            (org.apache.seatunnel.api.table.type.ArrayType<?, ?>) seaTunnelType;
                    org.apache.seatunnel.api.table.type.SeaTunnelDataType<?> elementType =
                            arrayType.getElementType();
                    if (elementType == null) {
                        throw new UnsupportedOperationException("ARRAY type requires element type");
                    }
                    return "array<" + seatunnelToHiveType(elementType) + ">";
                }
                throw new UnsupportedOperationException("ARRAY type requires element type");
            case MAP:
                if (seaTunnelType instanceof org.apache.seatunnel.api.table.type.MapType) {
                    org.apache.seatunnel.api.table.type.MapType<?, ?> mapType =
                            (org.apache.seatunnel.api.table.type.MapType<?, ?>) seaTunnelType;
                    org.apache.seatunnel.api.table.type.SeaTunnelDataType<?> keyType =
                            mapType.getKeyType();
                    org.apache.seatunnel.api.table.type.SeaTunnelDataType<?> valueType =
                            mapType.getValueType();
                    if (keyType == null || valueType == null) {
                        throw new UnsupportedOperationException(
                                "MAP type requires key and value types");
                    }
                    return "map<"
                            + seatunnelToHiveType(keyType)
                            + ","
                            + seatunnelToHiveType(valueType)
                            + ">";
                }
                throw new UnsupportedOperationException("MAP type requires key and value types");
            case NULL:
                throw new UnsupportedOperationException("Orc does not support NULL type");
            default:
                throw new UnsupportedOperationException(
                        String.format(
                                "Unsupported type conversion from %s to Hive ORC type",
                                seaTunnelType.getSqlType()));
        }
    }

View on GitHub (pinned to cf67b549a7)

Solutions

1. Rebuild the MapType with explicit non-null key and value types, e.g. new MapType<>(BasicType.STRING_TYPE, BasicType.LONG_TYPE).
2. Validate keyType != null && valueType != null before conversion.
3. Re-derive the schema from the source if it was deserialized from an incompatible version.

Example fix

// before
MapType<?, ?> bad = new MapType<>(BasicType.STRING_TYPE, null);
// after
MapType<String, Long> ok = new MapType<>(BasicType.STRING_TYPE, BasicType.LONG_TYPE);

if (mapType.getKeyType() == null || mapType.getValueType() == null) {
    throw new IllegalArgumentException("MapType must have non-null key and value types");
}

static boolean hasKeyAndValueTypes(MapType<?, ?> m) {
    return m != null && m.getKeyType() != null && m.getValueType() != null;
}

try {
    String hiveType = HiveTypeConvertor.seatunnelToHiveType(mapType);
} catch (UnsupportedOperationException e) {
    if (e.getMessage().contains("MAP type requires")) {
        // rebuild the MapType with concrete key/value types
    }
    throw e;
}

When it happens

Trigger: Calling seatunnelToHiveType on a MapType whose getKeyType() or getValueType() returns null — possible only with a manually built or corrupted MapType, since the API constructor normally enforces non-null types.

Common situations: Hand-constructed MapType with a null value type; schema deserialization across incompatible SeaTunnel API versions losing type info; reflection-based schema building that skipped nested types.

Related errors

• ROW type requires non-empty field names and types with equal
• ROW type requires non-empty field names and types
• ARRAY type requires element type
• Orc does not support NULL type
• Unsupported type conversion from %s to Hive ORC type

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/4de5b3d3a1e60045. Report an issue: GitHub.