alibaba/nacos · error · FileNotFoundException

{getDescription()} cannot be resolved in the file system for

Error message

{getDescription()} cannot be resolved in the file system for checking its content length

What it means

Thrown by AbstractFileResolvingResource.contentLength() when the resource resolves to a file-system URL, the File reports length 0, and the file does not actually exist. FileNotFoundException signals the resource path pointed nowhere on disk. If the URL is not a file URL, a URLConnection content-length is used instead and this branch is skipped.

Source

Thrown at common/src/main/java/com/alibaba/nacos/common/packagescan/resource/AbstractFileResolvingResource.java:233

    public ReadableByteChannel readableChannel() throws IOException {
        try {
            // Try file system channel
            return FileChannel.open(getFile().toPath(), StandardOpenOption.READ);
        } catch (FileNotFoundException | NoSuchFileException ex) {
            // Fall back to InputStream adaptation in superclass
            return super.readableChannel();
        }
    }

    @Override
    public long contentLength() throws IOException {
        URL url = getUrl();
        if (ResourceUtils.isFileUrl(url)) {
            // Proceed with file system resolution
            File file = getFile();
            long length = file.length();
            if (length == 0L && !file.exists()) {
                throw new FileNotFoundException(getDescription()
                        + " cannot be resolved in the file system for checking its content length");
            }
            return length;
        } else {
            // Try a URL connection content-length header
            URLConnection con = url.openConnection();
            customizeConnection(con);
            return con.getContentLengthLong();
        }
    }

    @Override
    public long lastModified() throws IOException {
        URL url = getUrl();
        boolean fileCheck = false;
        if (ResourceUtils.isFileUrl(url) || ResourceUtils.isJarUrl(url)) {
            // Proceed with file system resolution
            fileCheck = true;

View on GitHub (pinned to 9b989acdf1)

Solutions

1. Verify the file exists with Files.exists(Path) before calling contentLength().
2. For classpath resources that may live in jars, use getInputStream() rather than getFile()/contentLength() to avoid file-system resolution.
3. Fix the resource base path / working directory so resolution targets a real file.
4. Re-extract or redeploy the artifact so the referenced file is present.

Example fix

// before
long len = resource.contentLength(); // throws if file vanished

// after
File f = resource.getFile();
if (f.isFile()) {
    long len = f.length();
} else {
    try (InputStream in = resource.getInputStream()) {
        long len = in.readAllBytes().length;
    }
}

File f = resource.getFile();
if (!f.isFile()) {
    throw new FileNotFoundException("resource not on disk: " + f);
}
long len = resource.contentLength();

boolean isResolvableFile(Resource r) {
    try { return r.getFile().isFile(); }
    catch (IOException e) { return false; }
}

try {
    long len = resource.contentLength();
} catch (FileNotFoundException e) {
    log.warn("Resource missing on disk, falling back to stream: {}", e.getMessage());
}

When it happens

Trigger: Calling resource.contentLength() on a file:// (or a path resolved to File) whose target was deleted or never extracted; scanning resources where a listed class file is absent at runtime; a jar-extracted file path that no longer maps to disk.

Common situations: Deployed artifact references a file deleted during redeploy; a relative file resource resolved against a working directory that changed; classpath resource resolved to a file that is actually inside a jar (so getFile() returns a non-existent path); antivirus/quarantine removing a file after listing.

Related errors

• {getDescription()} cannot be resolved in the file system for
• {getDescription()} cannot be resolved to absolute file path
• {getDescription()} cannot be resolved in the file system for
• Cannot create a relative resource for {getDescription()}
• {getDescription()} cannot be opened because it does not exis

AI-assisted analysis of alibaba/nacos@9b989acdf1 (2026-08-14). Data as JSON: /api/errors/5b211cfb97926d26. Report an issue: GitHub.