JAVA Servlet Interview Questions and Answers

Explain the life cycle methods of a Servlet?

The javax.servlet.Servlet interface defines the three methods known as life-cycle method.
public void init(ServletConfig config) throws ServletException
public void service( ServletRequest req, ServletResponse res) throws ServletException, IOException
public void destroy()


First the servlet is constructed, then initialized wih the init() method. 
Any request from client are handled initially by the service() method before delegating to the doXxx() methods in the case of HttpServlet. 
The servlet is removed from service, destroyed with the destroy() method, then garbaged collected and finalized. 

What is the difference between the getRequestDispatcher(String path) method of javax.servlet.ServletRequest interface and javax.servlet.ServletContext interface?

The getRequestDispatcher(String path) method of javax.servlet.ServletRequest interface accepts parameter the path to the resource to be included or forwarded to, which can be relative to the request of the calling servlet. If the path begins with a "/" it is interpreted as relative to the current context root.

The getRequestDispatcher(String path) method of javax.servlet.ServletContext interface cannot accepts relative paths. All path must sart with a "/" and are interpreted as relative to curent context root.

Explain the directory structure of a web application?.

The directory structure of a web application consists of two parts. 
A private directory called WEB-INF
A public resource directory which contains public resource folder.
WEB-INF folder consists of 
1. web.xml
2. classes directory
3. lib directory

What are the common mechanisms used for session tracking?

Cookies
SSL sessions
URL- rewriting

Explain ServletContex?.
ServletContext interface is a window for a servlet to view it's environment. A servlet can use this interface to get information such as initialization parameters for the web application or servlet container's version. Every web application has one and only one ServletContext and is accessible to all active resource of that application.
What is preinitialization of a servlet?
A container doesnot initialize the servlets as soon as it starts up, it initializes a servlet when it receives a request for that servlet first time. This is called lazy loading. The servlet specification defines the element, which can be specified in the deployment descriptor to make the servlet container load and initialize the servlet as soon as it starts up. The process of loading a servlet before any request comes in is called preloading or preinitializing a servlet.

What is the difference between Difference between doGet() and doPost()?

A doGet() method is limited with 2k of data to be sent, and doPost() method doesn't have this limitation. A request string for doGet() looks like the following: 
http://www.abc.com/svt1?p1=v1&p2=v2&...&pN=vN
doPost() method call doesn't need a long text tail after a servlet name in a request. All parameters are stored in a request itself, not in a request string, and it's impossible to guess the data transmitted to a servlet only looking at a request string. 

What is the difference between HttpServlet and GenericServlet?

A GenericServlet has a service() method aimed to handle requests.
HttpServlet extends GenericServlet and adds support for doGet(), doPost(), doHead() methods (HTTP 1.0) plus doPut(), doOptions(), doDelete(), doTrace() methods (HTTP 1.1). Both these classes are abstract.

What is the difference between ServletContext and ServletConfig?

ServletContext: Defines a set of methods that a servlet uses to communicate with its servlet container, for example, to get the MIME type of a file, dispatch requests, or write to a log file.The ServletContext object is contained within the ServletConfig object, which the Web server provides the servlet when the servlet is initialized. 

ServletConfig: The object created after a servlet is instantiated and its default constructor is read. It is created to pass initialization information to the servlet.

Latest Updates

General Knowledge of India

‘Kanchipuram’ is in which of the following states?

General Knowledge of World

In which year was Pulitzer Prize established?

Indian History

The roads of cities in the Indus Valley Civilization generally divided the city into?

Which dynasty was ruling over North India when Alexander invaded India?

Who was the Spanish navigator who set out to discover India, but instead landed on the soil of America?

Who was the Viceroy of India, when Quit India Resolution was passed in 1942?

Order Sequence

There is a queue in a ticketing office. Amanda is 10​ th​ from the front while Murthy is 25​ th from behind and Marta is just in the middle of the two. If there be 50 persons in the queue. What position does Marta occupy from the front?

Direction

A man walks 5 Km towards south and then turns to the right. After walking 3 Km he turns to the left and walks 5 Km. Now in which direction is he from the starting place?

Series

Find the missing term: 60, 40, 55, 45, 50, 50,....?

Numbers

X is a whole number. If the only common factors of X and X2 are 1 and X, then X is _______?

Ratio and Proportion

An alloy contains copper and zinc in the ratio 5 : 3 and another contains copper and tin in the ratio 8 : 5, If equal weights of the two are melted together to form a 3​ rd​ alloy, find the weight of tin per kg in the new alloy?

Simplification

Aamir and Birju can cut 5000 g of wood in 20 min. Birju and Charles can cut 5000 g of wood in 40 min. Charles and Aamir can cut 5 kg of wood in 30 min. How much time Charles will take to cut 5 kg wood alone?

Compound Interest

The difference between the compound interest and the simple interest earned at the end of the third year on a sum of money at a rate of 10% per annum is Rs 77.5. What is the sum?

General Knowledge of MP

According to history, who established Gwalior?

General Knowledge of India

The headquarters of the Hindustan Aeronautics Limited is located at?

Indian Economy

The Reserve Bank of India was established in?

General Knowledge of MP

Who constructed the Chaturbhuj Temple of Orchha?

Highest peak in the Vindhya Range is the?

Latest Job Notifications

Jobs in West Bengal

इंडियन पोस्ट सर्विस Indian Post Service - 2357 पद - 19/08/2021 अंतिम तिथि - पश्चिम बंगाल पोस्टल सर्कल

Banking Jobs

भारतीय स्टेट बैंक State Bank of India(SBI) - 6100 पद - 26/07/2021 अंतिम तिथि - CRPD/APPR/2021-22/10

SSC Recruitment

कर्मचारी चयन आयोग Staff Selection Commission(SSC) - 25271 पद - 31/08/2021 अंतिम तिथि

Jobs in Madhya Pradesh

राष्ट्रीय स्वास्थ्य मिशन मध्य प्रदेश National Health Mission MP(NRHM) - 5215 पद - 22/06/2021 अंतिम तिथि

Jobs in Punjab

पंजाब स्टेट पावर कॉर्पोरेशन लिमिटेड Punjab State Power Corporation Limited (PSPCL) - 2632 पद - 20/06/2021 अंतिम तिथि

Jobs in Chhattisgarh

स्वास्थ्य सेवा निदेशालय, छत्तीसगढ़ Department of Health & Family Welfare, Chhattisgarh - 267 पद - 26/06/2021 अंतिम तिथि

Government Jobs

दिल्ली सबऑर्डिनेट सर्विस सिलेक्शन बोर्ड Delhi Subordinate Services Selection Board(DSSSB) - 5807 पद - 03/07/2021 अंतिम तिथि

Jobs in Madhya Pradesh

राष्ट्रीय स्वास्थ्य मिशन मध्य प्रदेश National Health Mission MP(NRHM) - 2850 पद - 31/05/2021 अंतिम तिथि

Government Jobs

इंडियन पोस्ट सर्विस Indian Post Service - 4368 पद - 29/05/2021 अंतिम तिथि

दिल्ली सबऑर्डिनेट सर्विस सिलेक्शन बोर्ड Delhi Subordinate Services Selection Board(DSSSB) - 7236 पद - 24/06/2021 अंतिम तिथि