apache/flink · error · RuntimeException

Can not create new instance for custom class from

Error message

Can not create new instance for custom class from %s

What it means

Thrown by createPolicyChain when the custom PartitionCommitPolicy class configured via sink.partition-commit.policy.class cannot be instantiated (class not found, constructor mismatch, reflective invocation or access failure).

Solutions

1. Address the cause reported by the error message: Can not create 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 create 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 create 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 create new instance for custom class from the reported value.

AI-assisted analysis of apache/flink@2f3c205e92 (2026-08-14). Data as JSON: /api/errors/6ce4577e8240570a. Report an issue: GitHub.

Appendix: source

Thrown at flink-connectors/flink-connector-files/src/main/java/org/apache/flink/connector/file/table/PartitionCommitPolicyFactory.java:92

                                                    parameters.toArray(new String[0]);
                                            Class<?>[] classes = new Class<?>[parameters.size()];
                                            for (int i = 0; i < parameters.size(); i++) {
                                                classes[i] = String.class;
                                            }
                                            return (PartitionCommitPolicy)
                                                    cl.loadClass(customClass)
                                                            .getConstructor(classes)
                                                            .newInstance((Object[]) paramStrings);
                                        } else {
                                            return (PartitionCommitPolicy)
                                                    cl.loadClass(customClass).newInstance();
                                        }
                                    } catch (ClassNotFoundException
                                            | IllegalAccessException
                                            | InstantiationException
                                            | NoSuchMethodException
                                            | InvocationTargetException e) {
                                        throw new RuntimeException(
                                                "Can not create new instance for custom class from "
                                                        + customClass,
                                                e);
                                    }
                                default:
                                    throw new UnsupportedOperationException(
                                            "Unsupported policy: " + name);
                            }
                        })
                .collect(Collectors.toList());
    }
}

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