Session Id problem in servlet

[harshad kadam]

Hello,
I have one simple login service implemented in a servlet.

if(jsnObj.has("username") && jsnObj.has("password"))
		{
			String username = jsnObj.getString("username");
			String password = jsnObj.getString("password");
			
			UserMaster userMaster = userMasterDao.getUserMasterByUserNamePassword(username, password);
			
			if(userMaster != null && userMaster.getId() != 0)
			{
				request.getSession().setAttribute("user_id", userMaster.getId());
				sessionId = request.getSession().getId();  //PLEASE_SEE_HERE
			}
			Date loggedInDate = new Date();
			String loggedInDateStr = Util.DateToString(loggedInDate, "dd-MM-yyyy");
			loginServiceJsonString = loginServiceBuildJson.loginJson(userMaster, sessionId, callback, loggedInDateStr);
		}

here i get the session id for this servlet context. To authenticate user later in other service, i have other method which matches the session id generated at after login, with currentSessId = request.getSession(false).getId();

                         if(op.equals("validate_sessid"))
			{
				authServiceBean = new AuthServiceBean();
				String currentSessId = request.getSession(false).getId();
				System.out.println("CURRENT_SESS_ID_AT_VALIDATE:\t"+currentSessId);
				String validateSession = authServiceBean.validateSession(request, param, callback, currentSessId);
				out.println(validateSession);
			}

where, validateSession method matches currentSessId with sessionId dat was generated at login time (which comes through URL request).

This approach is working fine when i access the this servlet through ip, means
http://192.168.5.9:8080/MyProj/MyServlet?_service=login&_param={%27username%27:%27admin%27,%20%27password%27:%27admin%27}

But when i access application through domain, it is creating new session Id every time i make the request.
http://local.myproj.com/MyServlet?_service=login&_param={%27username%27:%27admin%27,%20%27password%27:%27admin%27}


Please advice me what is going wrong here?