05/02/25
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Q)What is a servlet?
     =>A Servlet Container managed public Java class that implements
     Servlet interface is nothing but a servlet.
Q)What is the general structure of a servlet?
public class MyServlet implements Servlet{
      public void init(ServletConfig sc){
             //resources allocation for eg. database connection
      }
      public void service(ServletRequest request,ServletResponse response){
            //serving the client request(5 duties)
      }
      public void destroy(){
           //resources deallocation for eg. closing the database connection
      }
      ......
}
Q)What is the life cycle of a servlet?
    =>Servlet Container controls the life cycle of a servlet.
    =>3 life cycle methods and 4 life cycle phases describe the
    life cycle of a servlet.

    =>Life cycle methods are
                 1)init()
		 2)service()
		 3)destroy()

      =>Life cycle phases are
              1)instantiation phase
	      2)initialization phase
	      3)servicing phase
	      4)destruction phase

Instantiation phase
---------------------
Servlet Container creating the instance of a servlet class is nothing but
instantiation phase of the servlet.

initialization phase
-------------------
=>During instnatiation phase, servlet instance is there but it can't
serve the client request.

=>Servlet Container calling the init method on the servlet instance is nothing
but the initialization phase of the servlet.

=>Servlet Container calls init method only once in the life time of a servlet.

=>Once init method is completely executed, servlet instance is ready
to serve the client request.

=>Programmer can provide resources required for the
servlet  in init method.

destruction phase
--------------------
=>Servlet Container calling destroy() method on servlet instance 
is nothing but destruction phase.

=>Servlet Container calls destroy method only once in the life time of a servlet.

=>Programmer can release the  resources given to the
servlet  here. For eg. database connection closing