apache/seatunnel · error · IllegalArgumentException

Expected Array type but got:

Error message

Expected Array type but got: 

What it means

AerospikeSinkWriter.convertValue validates the runtime type of each field against the configured Aerospike data type; for the BYTEARRAY case the value's class must be an array, otherwise it throws IllegalArgumentException 'Expected Array type but got: <class>'. This enforces that the incoming SeaTunnel field actually holds a byte array before writing it as an Aerospike blob.

Solutions

1. Change the sink field's AEROSPIKE data type to match the actual incoming type (e.g. STRING)
2. Convert the upstream field to a byte[] in a transform before the sink
3. Fix the source schema so the field is emitted as byte[]
4. Check value.getClass() in the error message to identify the actual delivered type

Example fix

// before
field {
  name = payload
  type = { data_type = BYTEARRAY }
}
// after (upstream delivers String)
field {
  name = payload
  type = { data_type = STRING }
}

Object v = row.getField(idx);
if (!(v instanceof byte[])) throw new IllegalArgumentException("field 'payload' must be byte[] for BYTEARRAY, got " + v.getClass());

boolean isByteArray(Object v) { return v != null && v.getClass().isArray() && v.getClass().getComponentType() == byte.class; }

try { writer.write(row); } catch (AerospikeConnectorException e) { if (e.getCause() instanceof IllegalArgumentException && e.getCause().getMessage().startsWith("Expected Array type")) { /* fix schema or transform field */ } }

When it happens

Trigger: A record field configured as Aerospike type BYTEARRAY carries a non-array Java object (e.g. String, ByteBuffer, List) when write() calls convertValue.

Common situations: Source table column declared as string/varbinary mismatch; upstream connector delivers String while sink config expects BYTEARRAY; schema drift between source and sink.

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

• Expected List type but got:
• Cannot convert to struct:
• COMMON-07
• COMMON-19
• COMMON-19

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/6ae0c4511cc4ef57. Report an issue: GitHub.

Appendix: source

Thrown at seatunnel-connectors-v2/connector-aerospike/src/main/java/org/apache/seatunnel/connectors/seatunnel/aerospike/sink/AerospikeSinkWriter.java:212

                    return timestamp.orElseGet(() -> Long.parseLong((String) value));
                } else {
                    return Long.parseLong(value.toString());
                }
            case DOUBLE:
                if (value instanceof Number) {
                    return ((Number) value).doubleValue();
                }
                return Double.parseDouble(value.toString());
            case BOOLEAN:
                if (value instanceof Boolean) {
                    return value;
                }
                return Boolean.parseBoolean(value.toString());
            case BYTEARRAY:
                if (value.getClass().isArray()) {
                    return value;
                }
                throw new IllegalArgumentException(
                        "Expected Array type but got: " + value.getClass());
            case LIST:
                if (value instanceof Iterable) {
                    return value;
                }
                throw new IllegalArgumentException(
                        "Expected List type but got: " + value.getClass());
            default:
                throw new IllegalArgumentException("Unsupported AEROSPIKE data type: " + dataType);
        }
    }

    private long parseDateTimeString(String datetime) {
        try {
            return LocalDateTime.parse(datetime)
                    .atZone(ZoneId.systemDefault())
                    .toInstant()
                    .toEpochMilli();

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