Memory Management & Garbage Collection

Like Java, the CLR's garbage collector automatically reclaims objects no longer reachable — no manual free/delete. IDisposable (seen via using in Level 2) is for unmanaged resources (file handles, network sockets, database connections) that the garbage collector doesn't know how to release on its own timeline.

class FileWrapper : IDisposable {
    private FileStream _stream;

    public FileWrapper(string path) {
        _stream = File.OpenRead(path);
    }

    public void Dispose() {
        _stream.Dispose(); // release the OS file handle promptly
    }
}

using (var wrapper = new FileWrapper("data.txt")) {
    // ...
} // Dispose() called automatically here

Common mistakes

• Relying on the garbage collector alone to close a file or network connection "eventually" — it will, but not predictably; implement IDisposable and use using for anything holding a genuinely limited external resource.