I we disable cookies then it will bedifficult for the web 
container to manage the session with the help of cokkie.So 
we need to use the encodeURL() method for appending the 
jsessionid with the URL.

Cookies is used for identify to request.
if we disable the coookies then we cannot identify the 
request

It will give the exception saying that: "Illegal for 
useBean to use session scope when JSP page declares (via 
page directive) that it does not participate in sessions.
If you are not using the bean then it should be OK but most 
of the time it will generate the exceptions and container 
will not be able to manage the session for the page.

if we disable cookies then it cannot help us in the 
sessions,so we need to go for any other way,i.e., URL 
rewriting.In this URL rewriting we shud specify the 
jsessionid in the url itself..this mean we have to do 
little more work here,so best way to use cookies

if it cookies are disabled  it is hard to find the 
requesting users details. so it will be hard to maintain 
the session for the requesting user.

When there is no need to record/maintain the previous data 
of the user.

Like in google we are searching some infom
and after clicking on the searched item, it will forward to 
some other server or link, where there is no required to 
maintain any previous information of user.

that depends you need to think about the Scenario and use.

using cookies,url redirecting,

Using Seaaion Attribute

you can maintain session in 4 ways--
1. hidden form field eg.
<input type=hidden name=button1 value = butvalue>

2. Using cookie

3 . URL Rewriting

4 . Session Attribute - setAttrubute(key, value) and 
getAttribute(key)

In web.xml file, mention session attribute after
servlet-mapping. like this:
<session-config>
       <session-timeout>10</session-timeout> //10 mins
</session-config>

but the above ans is not suitable for any field like 
password.
that is for browser session out.
M i correct?

yes, u r right.
that is for session expiry.

when container sees the request for .jsp file it loads 
the .jsp file &converts into .java then compiles 
into .class file and it is servlet all the way(continer 
calss its no-arg constuctor,calss jspInit(),_jspservice()& 
finally jsp destory)

By using .jsp,we can compile in java, but it will executed 
in servlet

Jsp's are better choice as jsp can be easily turned to 
Servlets where the servlet container understands. 
As most of the projects run with java/j2ee, it is very easy 
to understand for the servlet engine, rather Asp being in 
third party language.

Jsp mens Java Server Pages it requires any java enabled web 
server for running and as we know that java is a sun 
product and Sun always comes with best product and JSp 
follows all java properties and it is a Object oriented 
base language.

ASP runs on microsoft related server.

Hi ur application was hacked by the some programmers..
u better develop one more application

Hey Tannu,
Can't u find some better project rather than a 500 year old
chatting application. Some 20lakh-50 lakh Chatting
applications are there on the net.

Start doing something interesting rather than some stupid
old chatting application.

Jsp is better for preparing presentation pages, while 
servlet is good for request processing as it's more 
difficult to write include, forward a static or dynamic url 
with in out.println() ,

Jsp has also all implicit objects, we need not have to 
instantiate any which is easier.

error handelling is easy in jsp isErrorPage="true" 
errorPage="/page"

we need not have to bother about init(),service(),destroy
(),doGet(),doPost()in jsp.

in servlet for each time changing we have to explicitly 
compile it.

Jsp automatically compiled by container when we reload the 
page.

Servlets are pure java programs.here we can't use HTML.
But in JSP we use HTML,so we can use and modify the data 
very easily.
   Servlets are faster than JSP.bcoz while running JSP 
programs it will be converted into Servlets and then 
executed,so it takes more time.

Servlets are pure java codes,here we can't used HTML.
But in JSP we can use HTML,so we can modify and also 
updated the data.
Another difference In Servlet  clientside validation is 
possible But in jsp clientside validation is not possible.

Both servlet and jsp are web components. But servlet is 
best suited for request processing, handling the business 
logic while jsp is suitable for content generating .Its 
easy to include html tag in jsp rather than servlet.Also 
jsp is compiled to servlet when first loaded to 
webserver.So in many framework servlet act as a controller 
while jsp as a view.Also implicit object and action 
elements available in jsp but not in servlet.

Jsp mainly used for the presentation only.It support only 
Http. whereas servlet support FTP,Http etc

1-The most important difference is that whenever we do some
changes in a servlet we need to build the application
completely but no need to do the same in case of jsp....

You can use the errorPage attribute of the page directive 
to have uncaught runtime exceptions automatically forwarded 
to an error processing page.
For example:
redirects the browser to the JSP page error.jsp if an 
uncaught exception is encountered during request 
processing. Within error.jsp, if you indicate that it is an 
error-processing page, via the directive: 
the Throwable object describing the exception may be 
accessed within the error page via the exception implicit 
object. 
Note: You must always use a relative URL as the value for 
the errorPage attribute.

My declarring errorpage attribute in page directive as
<% page errorPage="error.jsp"%>

and when u think that a jsp is supposed be encountered an 
error then <% page isErrorPage="true"%>