apache/cassandra · error · MarshalException

Expected a string representation of a time value, but got a

Error message

Expected a string representation of a time value, but got a %s: %s

What it means

TimeType.fromJSONObject expects the parsed JSON value for a time column to be a string in CQL time form (hh:mm:ss[.fff] or nanoseconds since midnight). Any non-string JSON value causes a ClassCastException, converted to this MarshalException.

Solutions

1. Send the time as a JSON string in CQL time format.
2. Convert numeric nanoseconds/millis to the string form client-side.
3. Validate the payload shape before submission.

Example fix

// before
{"t": 30600000}
// after
{"t": "08:30:00.000"}

if (!(parsed instanceof String)) throw new IllegalArgumentException("time must be an 'HH:mm:ss[.fff]' string");

boolean isTimeString(Object v) { return v instanceof String && v.toString().matches("\\d{2}:\\d{2}(:\\d{2}(\\.\\d{1,9})?)?"); }

try { return TimeType.instance.fromJSONObject(parsed); } catch (MarshalException e) { /* handle non-string JSON */ }

When it happens

Trigger: INSERT ... JSON / fromJson() where a time column receives a JSON number, boolean, null, array or object instead of a quoted time string like '08:30:00.123'.

Common situations: Clients sending milliseconds-since-midnight as a number; JS Date/time objects serialized as non-strings; null for missing times.

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 long or a datestring representation of a…

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/41ca34f0afb38392. Report an issue: GitHub.

Appendix: source

Thrown at src/java/org/apache/cassandra/db/marshal/TimeType.java:84

    {
        return ByteSourceInverse.getOptionalFixedLength(accessor, comparableBytes, 8);
    }

    @Override
    public boolean isValueCompatibleWithInternal(AbstractType<?> otherType)
    {
        return this == otherType || otherType == LongType.instance;
    }

    public Term fromJSONObject(Object parsed) throws MarshalException
    {
        try
        {
            return new Constants.Value(fromString((String) parsed));
        }
        catch (ClassCastException exc)
        {
            throw new MarshalException(String.format(
                    "Expected a string representation of a time value, but got a %s: %s", parsed.getClass().getSimpleName(), parsed));
        }
    }

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

    @Override
    public CQL3Type asCQL3Type()
    {
        return CQL3Type.Native.TIME;
    }

    @Override
    public TypeSerializer<Long> getSerializer()

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