When is the servlet instance created in the life cycle of servlet? What is the importance of configuring a servlet?

Servlet Interview Questions and Answers

(Continued from previous question...)

22. When is the servlet instance created in the life cycle of servlet? What is the importance of configuring a servlet?

An instance of servlet is created when the servlet is loaded for the first time in the container. Init() method is used to configure this servlet instance. This method is called only once in the life time of a servlet, hence it makes sense to write all those configuration details about a servlet which are required for the whole life of a servlet in this method.

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Other Interview Questions

• What is Servlet?
• Why is Servlet so popular?
• What is servlet container?
• When a client request is sent to the servlet container, how does the container choose which servlet to invoke?
• If a servlet is not properly initialized, what exception may be thrown?
• Given the request path below, which are context path, servlet path and path info?
• What is filter? Can filter be used as request or response?
• When using servlets to build the HTML, you build a DOCTYPE line, why do you do that?
• What is new in ServletRequest interface?(Servlet 2.4)
• Request parameter How to find whether a parameter exists in the request object?
• How can I send user authentication information while makingURLConnection?
• Can we use the constructor, instead of init(), to initialize servlet?
• How can a servlet refresh automatically if some new data has entered the database?
• The code in a finally clause will never fail to execute, right?
• What mechanisms are used by a Servlet Container to maintain session information?
• Difference between GET and POST
• What is session?
• What is servlet mapping?
• What is servlet context ?
• Which interface must be implemented by all servlets?
• Explain the life cycle of Servlet.
• When is the servlet instance created in the life cycle of servlet? What is the importance of configuring a servlet?
• Why don't we write a constructor in a servlet?
• When we don't write any constructor for the servlet, how does container create an instance of servlet?
• Once the destroy() method is called by the container, will the servlet be immediately destroyed? What happens to the tasks(threads) that the servlet might be executing at that time?
• What is the difference between callling a RequestDispatcher using ServletRequest and ServletContext?
• Why is it that we can't give relative URL's when using ServletContext.getRequestDispatcher() when we can use the same while calling ServletRequest.getRequestDispatcher()?