SESSION VARIABLE BECOMES NULL AFTER SOME REFRESH
Hi,
I have a jsp page which is refreshed atuomatically every 10 seconds.I
get and put values in the session by using the implicit session variable
. Everything works fine for say 2-3 mins after that the session becomes
null and throws a null pointer exception.
IN the try block I even have a code as
try {
if (session == null || session.isNew()) {
//do something
} else {
//do otherwise
}
}catch(Exception e )
{ //print stack trace and value of session }
I get a null pointer exception and session is preinted as null but even
the if block is noit executed . I printed the value of
request.getSession(false);.This gives me session object ,where as the
implicit session does not have this after many refresh interval . During
the first few refresh both have the same value.
Also note that this runs fine in Windows ,I get this problem only in
UNIX . I use tomcat 3.2 in unix and view using IE in windows
Please help me out as to where I am going wrong .
thanks and Regards
Mukund
RE: SESSION VARIABLE BECOMES NULL AFTER SOME REFRESH
Hi There,
The NPE is coming from the { if (session == null || session.isNew()) }
since even if session is null then you are still trying to call a method of
session.
a safer alternative would be
if (session == null) {
//error
} else {
if (session.isNew()) {
} else {
}
}
Thanks
Pete
-Original Message-
From: MUKUND Premchander [mailto:[EMAIL PROTECTED]
Sent: 12 April 2004 11:19
To: [EMAIL PROTECTED]
Subject: SESSION VARIABLE BECOMES NULL AFTER SOME REFRESH
Hi,
I have a jsp page which is refreshed atuomatically every 10 seconds.I
get and put values in the session by using the implicit session variable
. Everything works fine for say 2-3 mins after that the session becomes
null and throws a null pointer exception.
IN the try block I even have a code as
try {
if (session == null || session.isNew()) {
//do something
} else {
//do otherwise
}
}catch(Exception e )
{ //print stack trace and value of session }
I get a null pointer exception and session is preinted as null but even
the if block is noit executed . I printed the value of
request.getSession(false);.This gives me session object ,where as the
implicit session does not have this after many refresh interval . During
the first few refresh both have the same value.
Also note that this runs fine in Windows ,I get this problem only in
UNIX . I use tomcat 3.2 in unix and view using IE in windows
Please help me out as to where I am going wrong .
thanks and Regards
Mukund
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To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
RE: SESSION VARIABLE BECOMES NULL AFTER SOME REFRESH
Hi ,
Thank you for your reply .
Guess I did not put my qn the right way .
In the code block
if (session == null || session.isNew()
I do not access any session variables
Actually I just redirect the page.
I am unable to understand why the implicit session variable becomes null
suddenly after some refresh and why this occurs only when tomcat runs in
UNIX .I don't get this problem in Windows
Thanks and Regards
Mukund
-Original Message-
From: Peter Guyatt [mailto:[EMAIL PROTECTED]
Sent: Monday, April 12, 2004 4:10 PM
To: Tomcat Users List
Subject: RE: SESSION VARIABLE BECOMES NULL AFTER SOME REFRESH
Hi There,
The NPE is coming from the { if (session == null ||
session.isNew()) } since even if session is null then you are still
trying to call a method of session.
a safer alternative would be
if (session == null) {
//error
} else {
if (session.isNew()) {
} else {
}
}
Thanks
Pete
-Original Message-
From: MUKUND Premchander [mailto:[EMAIL PROTECTED]
Sent: 12 April 2004 11:19
To: [EMAIL PROTECTED]
Subject: SESSION VARIABLE BECOMES NULL AFTER SOME REFRESH
Hi,
I have a jsp page which is refreshed atuomatically every 10 seconds.I
get and put values in the session by using the implicit session variable
. Everything works fine for say 2-3 mins after that the session becomes
null and throws a null pointer exception.
IN the try block I even have a code as
try {
if (session == null || session.isNew()) {
//do something
} else {
//do otherwise
}
}catch(Exception e )
{ //print stack trace and value of session }
I get a null pointer exception and session is preinted as null but even
the if block is noit executed . I printed the value of
request.getSession(false);.This gives me session object ,where as the
implicit session does not have this after many refresh interval . During
the first few refresh both have the same value.
Also note that this runs fine in Windows ,I get this problem only in
UNIX . I use tomcat 3.2 in unix and view using IE in windows
Please help me out as to where I am going wrong .
thanks and Regards
Mukund
-
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
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To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
Re: SESSION VARIABLE BECOMES NULL AFTER SOME REFRESH
Peter Guyatt wrote:
Hi There,
The NPE is coming from the { if (session == null || session.isNew()) }
since even if session is null then you are still trying to call a method of
session.
According to Java language specification, 15.24 Conditional-Or
Operator ||, it's not so. That says that right-hand operator only
executes when left-hand operator is false, so in this code session!=null.
-Original Message-
From: MUKUND Premchander [mailto:[EMAIL PROTECTED]
Sent: 12 April 2004 11:19
To: [EMAIL PROTECTED]
Subject: SESSION VARIABLE BECOMES NULL AFTER SOME REFRESH
Hi,
I have a jsp page which is refreshed atuomatically every 10 seconds.I
get and put values in the session by using the implicit session variable
. Everything works fine for say 2-3 mins after that the session becomes
null and throws a null pointer exception.
IN the try block I even have a code as
try {
if (session == null || session.isNew()) {
//do something
} else {
//do otherwise
}
}catch(Exception e )
{ //print stack trace and value of session }
I get a null pointer exception and session is preinted as null but even
the if block is noit executed . I printed the value of
request.getSession(false);.This gives me session object ,where as the
implicit session does not have this after many refresh interval . During
the first few refresh both have the same value.
May be some logic deep in your code invalidates session somehow? You
can set up RequestDumperFilter to look at HTTP headers you (your
browser) send and what is received. I don't know if that filter
available in Tomcat 3.2, 'cause I use it since 4.1 time, but you can
grab it from recent Tomcat distribution. Or you can use
javax.servlet.http.HttpSessionListener to be notified when a session is
about to be invalidated or timed out.
Also note that this runs fine in Windows ,I get this problem only in
UNIX . I use tomcat 3.2 in unix and view using IE in windows
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