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.