1. What is a Servlet?
Servlet is a java object that provides the implementation of Servlet interface.
Servlet is a java object that provides the implementation of Servlet interface.
2. In which package
Servlet interface in present?
Servlet interface is present in javax.servlet package.
Servlet interface is present in javax.servlet package.
3. How many methods
does Servlet interface consist of?
Servlet interface consists of 5 methods.
Servlet interface consists of 5 methods.
4. List the methods
present in Servlet interface.
public void init(ServletConfig config)
public void init(ServletConfig config)
public ServletConfig getServletConfig()
public void
service(ServletRequest
request,ServletResponse response)
public String
getServletInfo()
public void destroy()
5.
What is life cycle
of a servlet?
The life cycle of
a servlet consists of three methods. They are init (), service () and destroy
().
6.
When init ()
method is invoked?
The init () method
is invoked when the servlet object is created.
7.
When service ()
method is invoked?
The service ()
method is invoked when we send a request to the servlet.
8.
When destroy ()
method is invoked?
The destroy ()
method is invoked when the servlet object is about to destroyed.
9. What are
ServletRequest and ServletResponse?
ServletRequest and ServletResponse are the interfaces present in javax.servlet package.
ServletRequest and ServletResponse are the interfaces present in javax.servlet package.
10. What is
ServletConfig?
ServletConfig is the interface present in javax.servlet package and this interface is used to get the init parameters to a single servlet.
ServletConfig is the interface present in javax.servlet package and this interface is used to get the init parameters to a single servlet.
11. How servlet object
is created?
Servlet object is created by web container like tomcat web server.
Servlet object is created by web container like tomcat web server.
12. What is the
limitation of Servlet interface?
Servlet interface consists of five methods. When we implement the servlet interface, we have to implement all the abstract methods present in that interface even though there is no use of the method. To overcome this limitation we can use a class known as HttpServlet class present in javax.servlet.http package.
Servlet interface consists of five methods. When we implement the servlet interface, we have to implement all the abstract methods present in that interface even though there is no use of the method. To overcome this limitation we can use a class known as HttpServlet class present in javax.servlet.http package.
13. What is
HttpServlet?
HttpServlet is the class present in javax.servlet.http package.
HttpServlet is the class present in javax.servlet.http package.
14. What is
ServletContext?
The servlet context is an object that contains information about the Web application and container. Using the context, a servlet can log events, obtain URL references to resources, and set and store attributes that other servlets in the context can use.
The servlet context is an object that contains information about the Web application and container. Using the context, a servlet can log events, obtain URL references to resources, and set and store attributes that other servlets in the context can use.
15. What is servlet
mapping?
The servlet mapping defines an association between a URL pattern and a servlet. The mapping is used to map requests to Servlets.
The servlet mapping defines an association between a URL pattern and a servlet. The mapping is used to map requests to Servlets.
16. What
are context initialization parameters?
Context initialization parameters are specified in the web.xml
file, these are initialization parameter for the whole application.
17. What
are initialization parameters?
Initialization parameters are specified in the web.xml file
under servlet tag, these are initialization parameter for a single servlet.
18.
What are different ways for session tracking?
Cookies, URL rewriting, HttpSession, Hidden form fields.
19.
What is the difference between GET and POST methods?
In GET, your entire form submission can be encapsulated in one
URL, like a hyperlink. Query length is limited to 255 characters, not secure,
faster, quick and easy. The data is submitted as part of URL.
In POST data is submitted inside body of the HTTP request. The data is not visible on the URL and it is more secure.
In POST data is submitted inside body of the HTTP request. The data is not visible on the URL and it is more secure.
20.
What is Redirection in a web application?
In Redirection,
when we give one url in the browser then we get output from another url. For Example,
when we give url like www.oldmail.com, then we get
output from www.newmail.com where both
websites belong to same company.
In Redirection,
there are multiple requests to execute multiple servlets.
21.
What are servlet configuration tags?
These are the tags
that are provided in web.xml and these tags provide information to the web
server which .class file is to be executed for a given request.
22.
How servlet configuration tags are written in web.xml.
23.What
is web.xml known as?
web.xml file is
known as deployment descriptor.
24.What
is a war file?
A war file
consists of the web information of a web application.
25.What
does lib folder consists of in a servlet web application?
The lib folder
consists of jar files which are required for a web application.
26.What
does classes folder consists of in a servlet web application?
The classes folder consists of .class
files which are executed in a web application.
27.What
is a web application?
A web application
is a set of web resources like html file or a servlet.
28.What
is root directory in a web application?
Root directory is
nothing but a project name given to a web application.
29.How
many web.xml files are present in a servlet web application?
There in only one
web.xml present in a servlet web application and this web.xml file is known as
deployment descriptor.
30.How
many servlet context objects are present in a servlet web application?
There in only one servlet context
object present in a servlet web application and this object is known as
application object.
31.What
is an application object present in servlet web application?
Servlet context
object is known as application object in servlet web application.
32.What
is RequestDispatcher?
RequestDispatcher
is an interface present in javax.servlet package and this interface consists of
two methods. They are include () and forward () methods.
33.What
is the difference between include () and forward () methods of
RequestDispatcher interface?
When we use
include () method, output from both servlets are included in the output.
Whereas when we
use forward () method, output is as that of redirection i.e. from second
servlet or last servlet.
34.What
is the difference between redirection and forward () method of
RequestDispatcher interface?
In redirection, there are multiple
requests to execute multiple servlets whereas in forward () method there is
single request to execute multiple servlets.
35.What
is a stateful protocol?
If the protocol
remembers the conversational state of a client then that protocol is known as
stateful protocol.
36.What
is a stateless protocol?
If the protocol
doesnot remembers the conversational state of a client then that protocol is
known as stateless protocol.
37.What
is http protocol?
http protocol is a
stateless protocol.
38.What
techniques are used to maintain the state of a client?
There are 3
techniques to maintain the state of a client. They are hidden fields, cookie
and session.
39.What
is a cookie?
Cookie is a small
piece of information that is set by the server on the browser.
Cookie is the
class present in javax.servlet.http package.
40.What
is session?
The session is an
object used by a servlet to track a user’s interaction with a web application
across multiple HTTP request. The session object is stored on the server.