If the struts configuration objects were to be created on 
the first call from the user it will adversely affect 
performance by delaying response for the first user.

By specifying load-on-startup = 1 we tell the servlet 
container to call the init() method immediately on start up 
of the servlet container.

If we use load on startup web container creates the objects 
based on the proirity when there are mutliple servlets.We 
use load on start up for giving the proirity.

If load_on_startup is not enabled in web.Xml then the
servlet crates the object that class and sevletConfig object
will be created after constructor will be executed after it
will go to life cycle methods in servlets.i.e means lot of
processing will be done when load-on-startup is not enabled.

If load_on_startup is enabled then that moment when
WEBAPPLICATION is deployed all lot of processing will be done.
Then immediately executes LIFECYCLE method in servlets  

Problem: suppose our webapplication contain 10 servlets then
which servlet object will be created?

solution: for this problem If we use load on startup web
container creates the objects based on the proirity when
there are mutliple servlets.We use load_ on_ start up for
giving the proirity.

Note:1 is highest priorty
     2 is next  highest priorty
    -1 ignores that value
EX:<load-on-startup>1</load-on-startup>

load_on_startup only shows the priority of the class loading
when u start ur web server in any web apps.

1----hightest prioritty
<load-on-startup>1</load-on-startup>

If we are using any of the custom tags related to struts
like <html:form> etc, then it compulsory we need the tag of
<load-on-startup> in web.xml then only we will get the
output of corresponding jsp on to the browse or else we will
get the some errors like ActionMapping cannot resolve...

To create the servlet objects  when the web application is 
started.

In Case of Struts Action servlet object is created when the 
application is started on proirity basis.We can specify 
some integer value for this in such cases servlets will be 
created on priority basis . Low value servlet will be 
created fisrt...