>Number: 4309
>Category: mod_jserv
>Synopsis: Problem serialiazing to/from file from within servlet
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: jserv
>State: open
>Class: sw-bug
>Submitter-Id: apache
>Arrival-Date: Mon Apr 26 07:40:00 PDT 1999
>Last-Modified:
>Originator: [EMAIL PROTECTED]
>Organization:
apache
>Release: 1.3.4 + 1.0b3
>Environment:
Solaris 2.6, JDK 1.2_01 Production release
>Description:
I am having a problem with a servlet, as described below:
My servlet collects up to two hours of data in a List. When I do something
that causes my servlet zone to reload all of the servlets, I would prefer that
the servlet didn't have to start collecting its data from scratch.
To avoid this, in the destroy method I write out (serialize) the data List
to a file. In the init method I read the data List back in if the file
exists.
The basic code in the destroy method:
os = new ObjectOutputStream(
new GZIPOutputStream(
new FileOutputStream(saveFile)));
os.writeObject(installations);
os.flush();
The basic code in the init method:
is = new ObjectInputStream(
new GZIPInputStream(
new FileInputStream(saveFile)));
installations = (List) is.readObject();
In order to give enough time to do the disk read/write, I have made the
following changes in the zone properties file:
init.timeout=120000
destroy.timeout=120000
After Apache is restarted, the init method successfully reads in an existing
file. If I do something that causes my servlet zone to reload all of the
servlets, the destroy method successfully writes out the file. However, on the
next initialization, the init method seems to freeze on the readObject() line
(CPU usage drops to 0, and nothing more appears in the logs, suggesting that
the next line never gets executed). I have to restart Apache - on the
subsequent init the file is read successfully, so I know it was written
properly in the destroy method.
Because this works once, I suspect that the problem is with Apache JServ, and
not with my code.
>How-To-Repeat:
>Fix:
>Audit-Trail:
>Unformatted:
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