JSP and Servlet Interview Question Part-1

Q1. What is the servlet?

Ans: Servlet is simple java class and it extending the functionality of a web server and that are execute on the server side.

It requires a servlet container to run .

Q2. Why we used servlet?

Ans:To handle client request and response(mostly in the from of HTTP/HTTPS request)or forward the request to another servlet or jsp

Q3. Explain Servlet Life cycle?

Ans: servlet life cycle controller by Servlet Container and container performs the following steps.

If an instance of the servlet does not exist ,web container

Step 1 :load the servlet class.

Step 2 :Creates an instance of the servlet class and initialize the servlet instance by calling the init() method.

Step 3 :Invokes the serivce method, passing a request and response object.

to the service()  method.

Step 4:If the container needs to remove the servlet,it finilizes the servlet by calling the servlet's destory method.

Q4. What are scope object available?

Ans:Enable sharing information between we application via attributes mentioned in the Scope objectAttributs mentained in scope Object are

access with setAttributs and getAttribute();

Q5. JSP implicity Object?

Ans: Request

        Responce

        PageContext

        Session

        applicaiton

        Out

        Config

        page

        exception

Q6. JSP Scope Object?

Ans:Page Scope   :a Single page

    Request Scope:Pages Processing the same request

    Session Scope:Pages processing the request that are in same session

    Application Scop : all pages in an application

Q 7 .What is Request Dispatcher?

When building a web application ,you want to forward processing to another component. or if you want to include the

processing of another component in the current response.

In Servlet API,we need to use a Request Dispatcher.This is retrieve from the ServletContext.

  public RequestDispatcher  getRequestDispatcher(String path)

The RequestDispatcher is create base on the path used to to obtain it(You must begin with a "/")

  public void forwared(ServletRequest request,ServletResponSe response)

  public void include(ServletRequest request ,ServletResponce response)

Q8. What is difference between SendRediresct and Forward?

Ans: When we used forward method request is transfer to other resource within the same server for further processing.

and in case sendRequest request is transfer is transfer to another resource to differance domain or different server for further processing.

Next difference is visually we are not able to see the forwarded address,it is transparent and in sendRedirect we are see the new redirected address it's not transparent