vijai sahu

can anybody tell me in my jsp application some time when i am clicking on hyperlink its redirect page to login page
due to geting data from session .how i can resolve this.the code snippet is
try
{
String sub_id=(String)session.getAttribute("subscriber_id");
sub_id=sub_id.trim();
System.out.println("Subscriber Id ="+sub_id);
}catch(Exception e)
{
System.out.println("Error in getting data from session!");
String urlE = "http://"+request.getServerName()+":"+request.getServerPort()+"/cdr/jsp/login.jsp";
response.sendRedirect(urlE);
}