Session Attribute Property Returns Null

[Steve Dyke]

I cannot figure out how this last line of this code fragment could return null.
I am checking for the validity of the session so this line of code should never be reached.

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		
		String lifecycle = "";
		try{lifecycle = (request.getParameter("lifecycle") != null?request.getParameter("lifecycle"):"");}catch(Exception e){}
		String jReturnString = "\"\"";
		RequestDispatcher disp = null;
		
		try{
			
			
			if(request.getSession(false) != null){
				
				final HttpSession session = request.getSession();
				final LogOn logOn = (LogOn)session.getAttribute("logonObj");
				final DefaultPrams dft = (DefaultPrams)session.getAttribute("defaultpramsObj");
				final SessionParms qmssessionParms = (SessionParms)session.getAttribute("QMSSessionParmsObj");
				
				
				if(lifecycle.equals("")){
					
					disp = getServletContext().getRequestDispatcher("/Layout/Layout-Misc/TimedOutDisplayForm.jsp");
					disp.forward(request, response);
					
				}
				else if(lifecycle.equals("initializencr")){
					
					session.removeAttribute("documentInitializeOptionsParmsObj");
					session.removeAttribute("documentItemV8Obj");
					session.removeAttribute("ncrV8Obj");
					
					dft.setErrorIndex(21);

[Paul Clapham]

The session may be "valid" but your problem is that the valid session doesn't include an attribute named "QMSSessionParmsObj". So line 15 assigns null to the dft variable.

It may be that lines 14 to 16 all assign null to those variables because the session attributes don't exist, but your line 31 is the first place where the code tries to use any of them.

[Steve Dyke]

Paul Clapham wrote:The session may be "valid" but your problem is that the valid session doesn't include an attribute named "QMSSessionParmsObj". So line 15 assigns null to the dft variable.

It may be that lines 14 to 16 all assign null to those variables because the session attributes don't exist, but your line 31 is the first place where the code tries to use any of them.

So since I assign these attributes when the session gets instantiated, I either have a request.getSession() called without the false parameter or I am removing the assigned attributes.

[Ron McLeod]

While I don't see how it could be a problem in the code that you posted, you do actually call getSession() without specifying setting the create parameter to false.

Maybe

final HttpSession session = request.getSession(false);		
if(session != null){
	...

instead of

if(request.getSession(false) != null){
	...
	final HttpSession session = request.getSession();

To debug, why not call the HttpSession#getAttributeNames method and iterate/log all the attribute names.