CsvParameterLayout throws NullPointerException on any event without parameters

[ramanathan1504]

Description

CsvParameterLayout.toSerializable passes Message.getParameters() to CSVFormat.printRecord with no null check. It is null for SimpleMessage, so every plain logger.info("some text") throws.

Only IOException is caught, so the NPE escapes to the appender: one error per event, no output, JVM exits 0. Parameterised calls work, so it survives testing and appears in production.

final Object[] parameters = message.getParameters();   // null for SimpleMessage
try {
    getFormat().printRecord(buffer, parameters);       // NPE
} catch (final IOException e) {                        // IOException only

Present on both lines:

• 2.x 04c93c1d33 — log4j-core/.../core/layout/CsvParameterLayout.java:98
• 3.x main — log4j-csv/.../csv/layout/CsvParameterLayout.java:104

Reproduced on 2.26.1, JDK 21.

Logs

ERROR An exception occurred processing Appender CsvParams
java.lang.NullPointerException: Cannot read the array length because "values" is null
	at org.apache.commons.csv.CSVFormat.printRecord(CSVFormat.java:2265)
	at CsvParameterLayout.toSerializable(CsvParameterLayout.java:98)

Reproduction

<File name="Csv" fileName="params.csv"><CsvParameterLayout format="Default"/></File>

logger.info("order {} accepted", 4711);   // fine
logger.info("plain text");                // NPE, file gains nothing

Suggested fix

getFormat().printRecord(buffer, parameters == null ? EMPTY : parameters);

An empty row is well-formed and matches the present-but-zero-length case. Widening the catch would stop the throw but leave the column count wrong, which is worse for a machine-read format.