Servlet Life Cycle. .can anybody say whether this is correct or not

Question

Hello everyone
Servlet Life Cycle.This is what i understood .can anybody say whether this is correct or not
According to sevlet specification,servlet life cycle has 4 stages
1)Loading and instantiation
2)Initialization
3)service the request
4)destroy
When we start webcontainer, webcontainer looks for deployed web applications and reads deployment descriptor of each web application.In the process of reading web.xml webcontainer container creates servletcontext object for holding context parameters and servletconfig object for holding servlet init-parameters after finding the servlet classes of the web application.
After finding the servlet classes webcontainer loads the servlet classes.
Loading can be done in 2 ways
1)When Webcontainer starts(loads) the webaplication by using load on startup in web.xml.
or
2)when first request comes for the webapplication
Say webcontainer starts the webaplication by using load on startup in web.xml ,Webcontainer creates an instance of servlet class and call init method of GenericServlet class by passing ServletConfig as parameter to init method i.e init(ServletConfig config).The code that is part of this init method initilize the ServletConfig variable of GenericServlet class and call init() method of GenericServlet class.
So when a request comes,webcontainer creates HttpServletRequest object,
HttpServletResponse object ,identifies the servlet class based onthe URL and
allocates a thread for the request and calls
service(ServletRequest req,ServletResponse resp) of HttpServlet class by
passing HttpServletRequest object, HttpServletResponse object as arguments.
Since req,resp are of type ServletRequest,ServletResponse they are type
casted to HttpServletRequest , HttpServletResponse and calls
service(HttpServletRequest req,HttpServletResponse resp) of HttpServletand
here request method is determined and either doGet()/doPost() methods are executed.
And finally when desroy method is called.

Answer 1

Mostly, but a servlet that has been initialized may service any number of 0 or more requests before being destroyed. So the life cycle might be:
1) Load
2) Initialize
3) Service a Request
4) Destroy
or
1) Load
2) Initialize
3) Service a Request
3) Service a Request
3) Service a Request
3) Service a Request
3) Service a Request
3) Service a Request
3) Service a Request
3) Service a Request
3) Service a Request
3) Service a Request
3) Service a Request
4) Destroy
or
1) Load
2) Initialize
4) Destroy
For any given <servlet> definition, you might have a combination of all:
1) Load (instance 1)
2) Initialize
4) Destroy
1) Load (instance 2)
2) Initialize
3) Service a Request
3) Service a Request
3) Service a Request
3) Service a Request
3) Service a Request
3) Service a Request
3) Service a Request
3) Service a Request
3) Service a Request
3) Service a Request
3) Service a Request
4) Destroy
1) Load (instance 3)
2) Initialize
3) Service a Request
4) Destroy
And for some Servlets with special configurations you might get:
1) Load (instance 1)
2) Initialize
1) Load (instance 2)
2) Initialize
1) Load (instance 3)
2) Initialize
3) Service a Request (instance 1)
3) Service a Request (instance 2)
3) Service a Request (instance 3)
3) Service a Request (instance 2)
3) Service a Request (instance 2)
3) Service a Request (instance 2)
3) Service a Request (instance 1)
3) Service a Request (instance 2)
3) Service a Request (instance 2)
3) Service a Request (instance 3)
3) Service a Request (instance 1)
4) Destroy (instance 1)
3) Service a Request (instance 2)
4) Destroy (instance 3)
4) Destroy (instance 2)
Finally, if you have multiple <servlet> entries in the web.xml (maybe with different servlet names and mappings) then you could have multiple parallel chains of this sort of life-cycle.
The key concept you have is correct. But once you understand that it is important to know that you really have no control over the lifecycle of the Servlet and that you should not assume anything about it.