apache/flink · error · RuntimeException

Can not new instance for custom class from %s

Error message

Can not new instance for custom class from %s

What it means

Error "Can not new instance for custom class from %s" thrown in apache/flink.

Source

Thrown at flink-connectors/flink-connector-files/src/main/java/org/apache/flink/connector/file/table/PartitionTimeExtractor.java:53

    LocalDateTime extract(List<String> partitionKeys, List<String> partitionValues);

    static PartitionTimeExtractor create(
            ClassLoader userClassLoader,
            String extractorKind,
            String extractorClass,
            String extractorPattern,
            String formatterPattern) {
        switch (extractorKind) {
            case DEFAULT:
                return new DefaultPartTimeExtractor(extractorPattern, formatterPattern);
            case CUSTOM:
                try {
                    return (PartitionTimeExtractor)
                            userClassLoader.loadClass(extractorClass).newInstance();
                } catch (ClassNotFoundException
                        | IllegalAccessException
                        | InstantiationException e) {
                    throw new RuntimeException(
                            "Can not new instance for custom class from " + extractorClass, e);
                }
            default:
                throw new UnsupportedOperationException(
                        "Unsupported extractor kind: " + extractorKind);
        }
    }
}

View on GitHub (pinned to 2f3c205e92)

Solutions

1. Address the cause reported by the error message: Can not new instance for custom class from the reported value
2. Verify the inputs, configuration values, and classpath/dependency setup related to this operation, then retry.

Example fix

Correct the condition described ("Can not new instance for custom class from the reported value") and rerun the job or command.

When it happens

Trigger: Triggered at runtime when the operation fails because: Can not new instance for custom class from the reported value.

Common situations: Commonly caused by misconfiguration, missing dependencies or files, unsupported types or operations, or invalid user input leading to: Can not new instance for custom class from the reported value.

AI-assisted analysis of apache/flink@2f3c205e92 (2026-08-14). Data as JSON: /api/errors/55fda11034a2b19e. Report an issue: GitHub.