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.

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.");

View on GitHub (pinned to 0152f468fc)

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

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

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