U5) Servlet and JSP

Question 1

What is a Servlet?

Answer 1

A Java class that handles HTTP requests in a web app and runs on a web server (e.g., Tomcat).

It is used to create dynamic web content.

Question 2

What is the architecture of a web application?

Answer 2

It follows a 3-tier model: Client (Browser),
Web Server (Servlet/JSP), and Database Server.

The Servlet runs in the middle layer (server-side).

Question 3

What is the HTTP protocol?

Answer 3

Rules for data exchange between browser and server.

Question 4

What are common HTTP methods?

Answer 4

GET: Request data,
POST: Send data,
PUT: Update data,
DELETE: Remove data.

Question 5

What is the difference between a Web Server and a Web Container?

Answer 5

A Web Server handles static content (HTML, CSS),

while a Web Container executes Servlets and JSP (e.g., Tomcat) and provides Servlet life cycle management.

Question 6

What are the main Servlet interfaces?

Answer 6

Servlet (base interface),

GenericServlet (abstract class for protocol-independent Servlets),

HttpServlet (handles HTTP-specific requests).

Question 7

What are the stages of the Servlet life cycle?

Answer 7

1. Initialization (init()): Called once when servlet loads.
2. Request (service()): Called for every request. 3. Destroy (destroy()): Called before unloading servlet.

Question 8

What is the difference between ServletConfig and ServletContext?

Answer 8

ServletConfig is per servlet and holds config parameters,

while ServletContext is application-wide and shared across servlets.

Question 9

How does Servlet communicate with a Browser?

Answer 9

Using sendError(code), setHeader(name, value), and sendRedirect(“url”).

Question 10

How do Servlets communicate with each other?

Answer 10

Using forward() to pass requests and include() to include responses from another servlet.

Question 11

What is a Session Object?

Answer 11

Server-side storage of user data.

Example:
HttpSession session = request.getSession(); session.setAttribute
(“name”,”King”);

Question 12

What are Cookies?

Answer 12

Small text files stored on the client side.

Example: Cookie c = new Cookie(“user”, “King”); response.addCookie(c);

Question 13

What is URL Rewriting?

Answer 13

Appending session data in the URL.

Example: /product.jsp?user=King

Question 14

What are Hidden Form Fields?

Answer 14

Data passed in HTML <input></input> fields.