If the If-Modified-Since header indicates that the content hasn't been modified since the provided date, the servlet should return a 304 Not Modified response to indicate that the client's cached copy is still valid.

The HttpSession feature in servlets is commonly used for session management, allowing the tracking and management of user sessions, which is essential for implementing user logins in web applications.

For transmitting sensitive data, such as during user logins, servlets should use HTTPS (HTTP Secure) to ensure data security through encryption.

The best approach for implementing user authentication based on roles in servlets is to use Container-Managed Security, which is configured in the deployment descriptor (web.xml) and utilizes the container's security mechanisms.

Servlet filters complement the MVC architecture by providing a mechanism to preprocess requests and post-process responses. They add a layer of functionality that can be applied across multiple components, enhancing the flexibility of the MVC design.

In an MVC framework, a servlet often delegates business logic processing to the controller layer, which is responsible for handling user input and coordinating the application's response.

The servlet forwards the processed data to the view using the forward mechanism, allowing the view to render the updated information based on the servlet's processing.

Servlets in an MVC framework typically receive user input through request parameters, which are data sent by the client as part of the HTTP request and can be accessed by the servlet.

The Front Controller pattern used in MVC frameworks centralizes request handling in a single servlet.

In the MVC framework, servlets are typically used to implement the Controller component, responsible for handling user input, processing requests, and interacting with the model and view components.