Top Ten Servlet Interview Inquiry Answers - J2ee

This fourth dimension its servlet interview questions, I was thinking what to selection for my interview serial too thus I idea nearly J2EE too Servlet is my favorite on that space. Servlet is an of import purpose of whatever J2EE evolution too serves equally Controller on many spider web MVC frameworks too that’s why it’s quite pop on J2EE interviews. These Servlet questions are based on my sense equally good equally collected past times friends too colleague too they are non alone proficient for interview do but besides shows a novel direction of learning for anyone who is non real familiar amongst servlet technology.

java interview questions , UNIX ascendence interview questions too Java threading interview questions.

You tin give notice abide by answers to all these questions on google but I convey besides listed my answers for quick reference.

Servlet Questions Asked inwards Interview

Question 1: In web.xml file   <load-on-startup>1</load-on-startup> is defined betwixt <servlet></servlet> tag what does it means. (detailed answer)

Ans: whenever nosotros asking for whatever servlet the servlet container volition initialize the servlet too charge it which is defined inwards our config file called web.xml past times default it volition non initialize when our context is loaded .defining similar this <load-on-startup>1</load-on-startup> is besides known equally pre-initialization of servlet way at i time the servlet for which nosotros convey defined this tag has been initialized inwards starting when context is loaded earlier getting whatever request.When this servlet inquiry was asked to me inwards an interview few years dorsum , I was non fifty-fifty aware of this chemical constituent but this questions pointed me to await DTD of web.xml too empathise other elements equally well.

Question 2: How tin give notice nosotros do deadlock status on our servlet? (detailed answer)

Ans: i uncomplicated way to telephone telephone doPost() method within doGet() too doGet()method within doPost() it volition do deadlock province of affairs for a servlet. This is rather a uncomplicated servlet interview questions but notwithstanding tricky if y'all don’t remember of it J

Question 3: For initializing a servlet tin give notice nosotros utilization a constructor inwards house of init()? (detailed answer)

Ans: No, nosotros tin give notice non utilization constructor for initializing a servlet because for initialization nosotros demand an object of servletConfig using this object nosotros acquire all the parameter which are defined inwards deployment descriptor for initializing a servlet too inwards servlet shape nosotros convey alone default constructor according to older version of coffee thus if nosotros desire to travel past times a Config object nosotros don’t convey parametrized constructor too apart from this servlet is loaded too initialized past times container thus it's a chore of container to telephone telephone the method according to servlet specification they convey lifecycle method so init() method is called firstly.

More of import Java doesn't allow interfaces to declare constructors. These kinds of servlet interview questions are quite pop on service based companies who merely desire to dig i score more. You tin give notice besides refer Programming Interviews Exposed for to a greater extent than of such questions. 

Question 4: Why super.init (config) is the source tilt within init(config) method. (detailed answer)

Ans: This volition last the source tilt if nosotros are overriding the init(config) method past times this way nosotros volition shop the config object for futurity reference too nosotros tin give notice utilization past times getServletConfig()  to acquire information nearly config object if volition non do this config object volition last lost too nosotros convey alone i way to acquire config object because servlet travel past times config object alone inwards init method . Without doing this if nosotros telephone telephone the ServletConfig method volition acquire NullPointerException.

Question5: Can nosotros telephone telephone destroy() method within the init() method is yep what volition happen? (detailed answer)

Ans: Yes nosotros tin give notice telephone telephone similar this but  if nosotros convey non overridden this method container volition telephone telephone the default method too zilch volition happen.after calling this if whatever nosotros convey overridden the method thus the code written within is executed.

Question 6: How tin give notice nosotros refresh servlet on customer too server side automatically? (detailed answer)

Ans: On the customer side nosotros tin give notice utilization Meta HTTP refresh too server side nosotros tin give notice utilization server push.

Question 7: How tin give notice y'all acquire the information nearly i servlet context inwards roughly other servlet? (detailed answer)

Ans: In context object nosotros tin give notice fix the attribute which nosotros desire on roughly other servlet too nosotros tin give notice acquire that attribute using their refer on roughly other servlet.

Context.setAttribute (“name”,” value”)

Context.getAttribute (“name”)

Question 8: Why nosotros demand to implement Single Thread model inwards the instance of Servlet. (detailed answer)

Ans: In J2EE nosotros tin give notice implement our servlet inwards 2 dissimilar ways either past times using:

1. Single Thread Model

2. Multithread Model

Depending upon our scenario, if nosotros convey implemented unmarried thread way alone i instance is going handgrip i asking at a fourth dimension no 2 thread volition concurrently execute service method of the servlet.

The example inwards banking accounts where sensitive information is handled to a greater extent than oftentimes than non this scenario was used this interface is deprecated inwards Servlet API version 2.4.

As the refer signifies multi-thread way a servlet is capable of treatment multiple requests at the same time. This servlet interview inquiry was quite pop few years dorsum on entry score but at i time it's losing its shine.

Question 9: What is servlet collaboration? (detailed answer)

Ans communication betwixt 2 servlets is called servlet collaboration which is achieved past times three ways.

1. RequestDispatchers include () too forward() method .

2. Using sendRedirect()method of Response object.

3. Using servlet Context methods

Question 10: What is the divergence betwixt ServletConfig too ServletContext? (detailed answer)

Ans: ServletConfig equally the refer implies furnish the information nearly the configuration of a servlet which is defined within the web.xml file or nosotros tin give notice tell deployment descriptor.its a specific object for each servlet.

ServletContext is an application specific object which is shared past times all the servlet belongs to i application inwards i JVM .this is a unmarried object which represents our application too all the servlet access application specific information using this object.servlet besides utilization their method to communicate amongst the container.

Question 11: Explain Servlet Life Cycle inwards Java EE environment?
Influenza A virus subtype H5N1 moving painting is worth K words, hither is a diagram which explains the Servlet life cycle:

Question 12: What is the divergence betwixt HttpServlet too GenericServlet inwards Servlet API? (answer)
GenericServlet provides framework to do a Servlet for whatever protocol e.g. y'all tin give notice write Servlet to have content from FTP, SMTP etc, spell HttpServlet is built-in Servlet provided past times Java for treatment HTTP requests. See detailed respond for deep discussion.

These Servlet interview questions are proficient for the quick recap of of import concept earlier appearing on whatever J2EE interview. Please portion if y'all convey come upwards across whatever other interesting interview inquiry on Servlets.

Further Learning
Java Web Fundamentals By Kevin Jones
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