apache/cassandra · error · MarshalException

Expected a long or a datestring representation of a…

Error message

Expected a long or a datestring representation of a timestamp value, but got a %s: %s

What it means

TimestampType.fromJSONObject accepts either a JSON string (datestring parseable by fromString) or a number (epoch millis). Any other JSON type raises ClassCastException which is wrapped as this MarshalException explaining both accepted forms.

Solutions

1. Send epoch-millis as a JSON number or a parseable date string (e.g. '2015-05-03 13:30:54.234').
2. Normalize client date objects to strings/millis before serialization.
3. Validate the JSON schema before submitting.

Example fix

// before
{"ts": {"$date": "2026-09-09T00:00:00Z"}}
// after
{"ts": "2026-09-09 00:00:00"}

if (!(parsed instanceof String || parsed instanceof Number)) throw new IllegalArgumentException("timestamp must be epoch-millis number or date string");

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

try { return TimestampType.instance.fromJSONObject(parsed); } catch (MarshalException e) { /* handle bad JSON type */ }

When it happens

Trigger: INSERT ... JSON / fromJson() where a timestamp column receives a JSON boolean, null, array or object rather than a string or number.

Common situations: ISODate/object serialization from MongoDB-style clients; null for missing timestamps; client sending nested objects for date fields.

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 a double value, but got a
• Expected a float value, but got a
• Expected a list, but got a
• Expected a list (representing a set), but got a
• Expected a map, but got a

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/10534b28ba825123. Report an issue: GitHub.

Appendix: source

Thrown at src/java/org/apache/cassandra/db/marshal/TimestampType.java:119

    @Override
    public long toTimeInMillis(ByteBuffer value)
    {
        return ByteBufferUtil.toLong(value);
    }

    @Override
    public Term fromJSONObject(Object parsed) throws MarshalException
    {
        if (parsed instanceof Long)
            return new Constants.Value(ByteBufferUtil.bytes((Long) parsed));

        try
        {
            return new Constants.Value(TimestampType.instance.fromString((String) parsed));
        }
        catch (ClassCastException exc)
        {
            throw new MarshalException(String.format(
                    "Expected a long or a datestring representation of a timestamp value, but got a %s: %s",
                    parsed.getClass().getSimpleName(), parsed));
        }
    }

    private String toString(Date date)
    {
        return date != null ? TimestampSerializer.getJsonDateFormatter().format(date.toInstant()) : "";
    }

    @Override
    public String toJSONString(ByteBuffer buffer, ProtocolVersion protocolVersion)
    {
        return '"' + toString(TimestampSerializer.instance.deserialize(buffer)) + '"';
    }

    @Override
    public boolean isCompatibleWith(AbstractType<?> previous)

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