MuntashirAkon/AppManager · error · FileNotFoundException

+ path + does not exist.

Error message

+ path + does not exist.

What it means

VirtualFileSystem.newInputStream(path) throws FileNotFoundException when getNode(path) returns null, i.e. the path does not resolve to a node in this virtual filesystem. The library requires the target to exist (and be a readable file) before opening an input stream. Unlike java.io.FileInputStream, existence is checked against the VFS tree, not the raw OS filesystem.

Solutions

1. Verify the path exists first via VFS exists()/ls on the parent directory before calling newInputStream
2. Check for races: ensure no other thread/process deletes the entry between creation and read
3. Re-check the path string for typos, casing, and the VFS's expected separator
4. If the source was unmounted/remounted, re-resolve the path against the new mount instead of reusing a stale absolute path

Example fix

// before
FileInputStream in = vfs.newInputStream("/docs/config.json");
// after
if (vfs.exists("/docs/config.json")) {
    FileInputStream in = vfs.newInputStream("/docs/config.json");
} else {
    // create, mount, or surface a user-facing "file missing" state
}

if (vfs == null || !vfs.exists(path)) throw new IllegalStateException("VFS path missing: " + path);

boolean isReadableFile(VirtualFileSystem vfs, String path) {
    try {
        return vfs.checkAccess(path, OsConstants.R_OK);
    } catch (IOException e) {
        return false;
    }
}

try {
    FileInputStream in = vfs.newInputStream(path);
} catch (FileNotFoundException e) {
    // path missing in VFS: recreate/mount or inform user
} catch (IOException e) {
    // access or type problem
}

When it happens

Trigger: Calling newInputStream() with a path that was never created/mounted in the VFS, a path that was deleted (or whose node was evicted from the VFS cache), or a misspelled/incorrectly-cased path. Also when checkAccess(R_OK) passes but the node lookup fails (e.g. dangling entry after an unmount).

Common situations: Opening a file before the remote source is mounted or lazily populated; racing with a delete/removal from another thread; constructing paths with wrong separators or case; stale path cached from a previous mount session.

Understand the failure class

Background: "File not found" and ENOENT errors: why libraries can't find a file that should exist — this error's family across 50 libraries.

Related errors

• Bad mode: + mode
• + path + cannot be opened for both reading.
• + path + cannot be opened for both reading and writing.
• + path + cannot be opened for both writing.
• + path + is not a file.

AI-assisted analysis of MuntashirAkon/AppManager@0152f468fc (2026-09-12). Data as JSON: /api/errors/954cde588a3db369. Report an issue: GitHub.

Appendix: source

Thrown at app/src/main/java/io/github/muntashirakon/io/fs/VirtualFileSystem.java:968

    public void setUidGid(String path, int uid, int gid) {
        // TODO: 7/12/22 This should either throw ErrnoException or a boolean value
        checkMounted();
    }

    public boolean createLink(String link, String target, boolean soft) {
        checkMounted();
        return false;
    }

    /* I/O APIs */
    @NonNull
    public FileInputStream newInputStream(String path) throws IOException {
        if (!checkAccess(path, OsConstants.R_OK)) {
            throw new IOException(path + " is inaccessible.");
        }
        Node<?> targetNode = getNode(path);
        if (targetNode == null) {
            throw new FileNotFoundException(path + " does not exist.");
        }
        if (!targetNode.isFile()) {
            throw new IOException(path + " is not a file.");
        }
        return new FileInputStream(getCachedFile(targetNode, false));
    }

    @NonNull
    public FileOutputStream newOutputStream(String path, boolean append) throws IOException {
        if (!checkAccess(path, OsConstants.W_OK)) {
            throw new IOException(path + " is inaccessible.");
        }
        Node<?> targetNode = getNode(path);
        if (targetNode == null) {
            throw new FileNotFoundException(path + " does not exist.");
        }
        if (!targetNode.isFile()) {
            throw new IOException(path + " is not a file.");

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