apache/flink · error · RuntimeException

File {} exists and overwriting is not allowed

Error message

File {} exists and overwriting is not allowed

What it means

ParameterTool.createPropertiesFile(path, overwrite) refuses to clobber an existing file when overwrite is false, throwing RuntimeException after the exists() check. With overwrite=true it deletes the existing file first. The method then writes the tool's defaultData as a properties file.

Source

Thrown at flink-core/src/main/java/org/apache/flink/util/ParameterTool.java:271

    public void createPropertiesFile(String pathToFile) throws IOException {
        createPropertiesFile(pathToFile, true);
    }

    /**
     * Create a properties file with all the known parameters (call after the last get*() call). Set
     * the default value, if overwrite is true.
     *
     * @param pathToFile Location of the default properties file.
     * @param overwrite Boolean flag indicating whether or not to overwrite the file
     * @throws IOException If overwrite is not allowed and the file exists
     */
    public void createPropertiesFile(String pathToFile, boolean overwrite) throws IOException {
        final File file = new File(pathToFile);
        if (file.exists()) {
            if (overwrite) {
                file.delete();
            } else {
                throw new RuntimeException(
                        "File " + pathToFile + " exists and overwriting is not allowed");
            }
        }
        final Properties defaultProps = new Properties();
        defaultProps.putAll(this.defaultData);
        try (final OutputStream out = new FileOutputStream(file)) {
            defaultProps.store(
                    out, "Default file created by Flink's ParameterUtil.createPropertiesFile()");
        }
    }

    @Override
    protected Object clone() throws CloneNotSupportedException {
        return new ParameterTool(this.data);
    }

    // ------------------------- Interaction with other ParameterUtils -------------------------

View on GitHub (pinned to 2f3c205e92)

Solutions

1. Pass overwrite=true if regenerating the file is intended.
2. Or delete/archive the existing file before re-running the setup step.
3. Make creation conditional: only call createPropertiesFile when the file is absent.

Example fix

// before
params.createPropertiesFile(path, false); // second run throws

// after
params.createPropertiesFile(path, true);
// or: if (!new File(path).exists()) params.createPropertiesFile(path, false);

File f = new File(pathToFile);
if (f.exists()) { /* archive or reuse existing file instead of recreating */ } else { params.createPropertiesFile(pathToFile, false); }

When it happens

Trigger: Calling createPropertiesFile(path, false) when path already exists — e.g. re-running a job initialization step on the same machine without cleanup.

Common situations: Idempotent-looking setup code executed twice (retry, restart, re-deploy); shared state dir between runs; scripts that do not remove generated config between executions.

Related errors

• Properties file {} does not exist
• Configuration cannot evaluate value %s as a byte[] value
• Value for config option %s must be one of %s (was %s)
• Could not parse value for key '%s'.
• Could not parse value '%s' for key '%s'.

AI-assisted analysis of apache/flink@2f3c205e92 (2026-08-14). Data as JSON: /api/errors/e3e26823c14699cb. Report an issue: GitHub.