alibaba/nacos · error · FileNotFoundException

cannot be resolved in the file system for checking its…

Error message

{getDescription()} cannot be resolved in the file system for checking its last-modified timestamp

What it means

Thrown by the default AbstractResource.lastModified() (the AbstractResource version, distinct from AbstractFileResolvingResource) when getFileForLastModifiedCheck() returns a File whose lastModified() is 0 and which does not exist. FileNotFoundException indicates the resource could not be resolved to an existing file for timestamp checking.

Solutions

1. Check the file exists (file.exists()) before calling lastModified().
2. Override getFileForLastModifiedCheck() in your subclass to return a real, existing File, or rely on a URL-based timestamp.
3. Catch FileNotFoundException and treat timestamp as unknown rather than fatal.
4. Use AbstractFileResolvingResource (URL-connection fallback) instead of bare AbstractResource if the resource may not be file-backed.

Example fix

// before
long ts = resource.lastModified(); // throws if file missing

// after
File f = resource.getFileForLastModifiedCheck();
long ts = f.exists() ? f.lastModified() : -1L;

File f = resource.getFileForLastModifiedCheck();
if (!f.exists()) {
    return -1L;
}
return resource.lastModified();

boolean hasFileTimestamp(Resource r) {
    try { return r.getFileForLastModifiedCheck().exists(); }
    catch (IOException e) { return false; }
}

try {
    long ts = resource.lastModified();
} catch (FileNotFoundException e) {
    log.debug("No file for timestamp: {}", e.getMessage());
    ts = -1L;
}

When it happens

Trigger: Calling lastModified() on an AbstractResource subclass where getFileForLastModifiedCheck() (defaulting to getFile()) returns a non-existent path; resource that has no file representation so getFile() yields a phantom path.

Common situations: A resource subclass whose getFile() returns a path inside a jar or a deleted file; stale resource handle after the underlying file was removed; subclass that overrode getFileForLastModifiedCheck() to return a wrong path.

Related errors

• Cannot create a relative resource for
• cannot be resolved in the file system for checking its…
• cannot be resolved in the file system for checking its…
• cannot be resolved to absolute file path
• cannot be opened because it does not exist

AI-assisted analysis of alibaba/nacos@9b989acdf1 (2026-08-14). Data as JSON: /api/errors/52ea33e5d8dd946f. Report an issue: GitHub.

Appendix: source

Thrown at common/src/main/java/com/alibaba/nacos/common/packagescan/resource/AbstractResource.java:191

                if (logger.isDebugEnabled()) {
                    logger.debug("Could not close content-length InputStream for " + getDescription(), ex);
                }
            }
        }
    }

    /**
     * This implementation checks the timestamp of the underlying File,
     * if available.
     *
     * @see #getFileForLastModifiedCheck()
     */
    @Override
    public long lastModified() throws IOException {
        File fileToCheck = getFileForLastModifiedCheck();
        long lastModified = fileToCheck.lastModified();
        if (lastModified == 0L && !fileToCheck.exists()) {
            throw new FileNotFoundException(getDescription()
                    + " cannot be resolved in the file system for checking its last-modified timestamp");
        }
        return lastModified;
    }

    /**
     * Determine the File to use for timestamp checking.
     * The default implementation delegates to {@link #getFile()}.
     *
     * @return the File to use for timestamp checking (never {@code null})
     * @throws FileNotFoundException if the resource cannot be resolved as
     *                               an absolute file path, i.e. is not available in a file system
     * @throws IOException           in case of general resolution/reading failures
     */
    protected File getFileForLastModifiedCheck() throws IOException {
        return getFile();
    }

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