CoolInterview.com - World's Largest Collection of Interview Questions & Answers, FAQs, queries, sample papers, exam papers, dumps, what, why, how, where, when questions
Our Services
Get 9,000 Interview Questions & Answers in an eBook.




Get it now !!
Send your Resume to 6000 Companies

Search Interview Questions

Question: What is the difference between GenericServlet and HttpServlet?

Answer: GenericServlet is for servlets that might not use HTTP, like for instance FTP service.As of only Http is implemented completely in HttpServlet. The GenericServlet has a service() method that gets called when a client request is made. This means that it gets called by both incoming requests and the HTTP requests are given to the servlet as they are.



Category Servlet Interview Questions & Answers - Exam Mode / Learning Mode
Rating (3.5) By 44 users
Added on 10/25/2009
Views 3284
Rate it!
Question: What is the difference between GenericServlet and HttpServlet?
Answer:

GenericServlet is for servlets that might not use HTTP, like for instance FTP service.As of only Http is implemented completely in HttpServlet. The GenericServlet has a service() method that gets called when a client request is made. This means that it gets called by both incoming requests and the HTTP requests are given to the servlet as they are. Source: CoolInterview.com


Generic Servlet:- A GenericServlet has a service() method to
handle requests. It is protocol independent.

Http Servlet:- The HttpServlet extends GenericServlet and adds support for HTTP protocol based methods like doGet(), doPost(), doHead() etc. It is protocol dependent. Source: CoolInterview.com

Answered by: modi | Date: 2/2/2009 | Contact modi Contact modi

GenericServlet is not specific any protocol .The GenericServlet has a service()method that gets called when a client request is made.

But HttpServlet is specific to Http protocol Source: CoolInterview.com

Answered by: Anirudh Narayan | Date: 5/2/2009 | Contact Anirudh Narayan Contact Anirudh Narayan

When one writes a Servlet code, he must implement this interface directly or indirectly. Here, one always implements the interface indirectly by extending either the javas.servlet.GenericServlet or javax.servlet.http.HttpServlet classes.

The GenericServlet class implements the Servlet interface and, for convenience, the ServletConfig interface. Servlet developers typically subclass GenericServlet, or its descendent HttpServlet, unless the Servlet needs another class as a parent. (If a Servlet does need to subclass another class, the Servlet must implement the Servlet interface directly. This would be necessary when, for example, RMI or CORBA objects act as Servlets.)
The GenericServlet class was created to make writing Servlets easier. It provides simple versions of the life-cycle methods init() and destroy( ), and of the methods in the ServletConfig interface. It also provides a log method, from the ServletContext interface. The Servlet writer must override only the service method, which is abstract. Though not required, the Servlet implementer should also override the getServletInfo() method, and will want to specialize the init and destroy methods if expensive Servlet-wide resources are to be managed.


The HttpServlet class extends GenericServlet, and provides an HTTP specific implementation of the Servlet interface. This class containing the following methods:
i. The service( ) method:
protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, java.io.IOException

This method Receives standard HTTP requests from the public service method and dispatches them to the doXXX methods defined in this class. This method is an HTTP-specific version of the Servlet.service(javax.servlet.ServletRequest, javax.servlet.ServletResponse) method. There's no need to override this method.


ii. The doXXX( ) Methods:
a. protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, java.io.IOException

b. protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, java.io.IOException

c. protected void doPut(HttpServletRequest req, HttpServletResponse resp) throws ServletException, java.io.IOException

d. protected void doDelete(HttpServletRequest req, HttpServletResponse resp) throws ServletException, java.io.IOException

e. protected void doOptions(HttpServletRequest req, HttpServletResponse resp) throws ServletException, java.io.IOException

f. protected void doTrace(HttpServletRequest req, HttpServletResponse resp) throws ServletException, java.io.IOException
The signature of the each of these doXXX() methods is the same as the protected service() method.
The HttpServlet class provides proper implementations for the TRACE and OPTIONS methods, and there is no need to override doTrace() and doOptions().
For the other five methods, the HttpServlet class provides implementations that return HTTP errors. For the case of HTTP 1.0 complaint containers, these method return an HTTP error with status code 400, indicating that the request sent by the client is syntactically incorrect. For HTTP 1.1 complaint containers, these methods returns an HTTP error with status code 405, indicating that the requested HTTP method is not allowed for this Servlet. This class uses the getProtocol() method of the javax.servlet.ServletRequest interface to determine the protocol.
iii. The getLastModified() Method:
protected long getLastModified(HttpServletRequest req)

This method returns the time the HttpServletRequest object was last modified, in milliseconds since midnight January 1, 1970 GMT. If the time is unknown, this method returns a negative number (the default).
Servlets that support HTTP GET requests and can quickly determine their last modification time should override this method. This makes browser and proxy caches work more effectively, reducing the load on server and network resources.
Source: CoolInterview.com

Answered by: Sankhadip | Date: 5/29/2009 | Contact Sankhadip Contact Sankhadip

GenericServlet has service() method, to handle client request.
HttpServlet extends GenericServlet.
HttpServlet has init(),service(),destroy() methods.Both are abstract. Source: CoolInterview.com

Answered by: Selva.D | Date: 9/6/2009 | Contact Selva.D Contact Selva.D


If you have the better answer, then send it to us. We will display your answer after the approval

Rules to Post Answers in CoolInterview.com:-

  • There should not be any Spelling Mistakes.
  • There should not be any Gramatical Errors.
  • Answers must not contain any bad words.
  • Answers should not be the repeat of same answer, already approved.
  • Answer should be complete in itself.

Post your answer here

Inform me about updated answers to this question.
Related Questions
View Answer
What are the differences between GET and POST service methods?
View Answer
What is the difference between ServletContext and ServletConfig?
View Answer
Can I invoke a JSP error page from a servlet?
View Answer
Can I just abort processing a JSP?
View Answer
What is a better approach for enabling thread-safe servlets and JSPs? SingleThreadModel Interface or Synchronization?
View Answer
If you want a servlet to take the same action for both GET and POST request, what should you do?
View Answer
What is the servlet life cycle?
View Answer
Which code line must be set before any of the lines that use the PrintWriter?
View Answer
How HTTP Servlet handles client requests?
View Answer
What is the Servlet Interface?
View Answer
When a servlet accepts a call from a client, it receives two objects. What are they?
View Answer
What information that the ServletRequest interface allows the servlet access to?
View Answer
What information that the ServletResponse interface gives the servlet methods for replying to the client?
View Answer
What is the servlet?
View Answer
What are the uses of Servlets?
View Answer
What are the advantages using servlets than using CGI?
View Answer
What is the difference between servlets and applets?
View Answer
Difference between single thread and multi thread model serv
View Answer

Please Note: We keep on updating better answers to this site. In case you are looking for Jobs, Pls Click Here Vyoms.com - Best Freshers & Experienced Jobs Website.

View All Servlet Interview Questions & Answers - Exam Mode / Learning Mode




India News Network
Latest 20 Questions
An offer which is open for acceptance over a period of time is: (a) Cross Offer (b) Counter Offer (c) Standing Offer (d) Implied Offer
Specific offer can be communicated to__________ (a) All the parties of contract (b) General public in universe (c) Specific person (d) None of the above
_________ amounts to rejection of the original offer. (a) Cross offer (b) Special offer (c) Standing offer (d) Counter offer
A advertises to sell his old car by advertising in a newspaper. This offer is caleed: (a) General Offer (b) Special Offer (c) Continuing Offer (d) None of the above
In case a counter offer is made, the original offer stands: (a) Rejected (b) Accepted automatically (c) Accepted subject to certain modifications and variations (d) None of the above
In case of unenforceable contract having some technical defect, parties (a) Can sue upon it (b) Cannot sue upon it (c) Should consider it to be illegal (d) None of the above
If entire specified goods is perished before entering into contract of sale, the contract is (a) Valid (b) Void (c) Voidable (d) Cancelled
______________ contracts are also caled contracts with executed consideration. (a) Unilateral (b) Completed (c) Bilateral (d) Executory
A offers B to supply books @ Rs 100 each but B accepts the same with condition of 10% discount. This is a case of (a) Counter Offer (b) Cross Offer (c) Specific Offer (d) General Offer
_____________ is a game of chance. (a) Conditional Contract (b) Contingent Contract (c) Wagering Contract (d) Quasi Contract
There is no binding contract in case of _______ as one's offer cannot be constructed as acceptance (a) Cross Offer (b) Standing Offer (c) Counter Offer (d) Special Offer
An offer is made with an intention to have negotiation from other party. This type of offer is: (a) Invitation to offer (b) Valid offer (c) Voidable (d) None of the above
When an offer is made to the world at large, it is ____________ offer. (a) Counter (b) Special (c) General (d) None of the above
Implied contract even if not in writing or express words is perfectly _______________ if all the conditions are satisfied:- (a) Void (b) Voidable (c) Valid (d) Illegal
A specific offer can be accepted by ___________. (a) Any person (b) Any friend to offeror (c) The person to whom it is made (d) Any friend of offeree
An agreement toput a fire on a person's car is a ______: (a) Legal (b) Voidable (c) Valid (d) Illegal
"Holiday Packages" announced as an advertisement are an example of _________: (a) Offer (b) Counter Offer (c) Invitation to Offer (d) None of the above
A match fixing contract between a player and a broker is a: (a) Valid Contract (b) Unenforceable Contract (c) Void Contract (d) Illegal Contract
When a bookseller sells a book on cash payment then it is called as ___________: (a) Unilateral Contract (b) Bilateral Contract (c) Executed Contract (d) Executory Contract
____________ agreements are created by situation: (a) Written (b) Oral (c) Void (d) Implied
Cache = 0.046875 Seconds