Re: conflict with automatic session serialization by tomcat?

From: Andrus Adamchik (andru..bjectstyle.org)
Date: Tue Jul 06 2004 - 15:22:14 EDT

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    Hi Twan,

    What version of Cayenne and Tomcat are you using?

    I just tried a very simple JSP app with the latest Cayenne (I used a
    CVS HEAD version, though M7_1 should be the same) and vanilla
    installation of Tomcat 4.1.27, and I don't have any problems. Caching
    just works. I get no exceptions on startup and I get my session state
    back as expected.

    Could you write a test app that reproduces a problem? If so, please
    submit a bug report and attach such app.

    Thanks
    Andrus

    On Jul 6, 2004, at 2:53 PM, Twan Kogels wrote:

    > Hello,
    >
    > I did find a very dirty solution: Tomcat 4.x doesn't seem to have
    > functionality to disable restart persistence. But when using:
    >
    > <Manager className="org.apache.catalina.session.StandardManager"
    > debug="0"
    > pathname="">
    > </Manager>
    >
    > in server.xml with a empty pathname the restart persistence is
    > disabled. Not really disabled though, because when tomcat shutdown it
    > will produce a lot of filenotfound exceptions. This is because a empty
    > pathname is no valid filename. But the advantage is that sessions.ser
    > isn't written anymore, so restart persistence is disabled. A bit
    > crude, but it seems to work.
    >
    > A better solution is still welcome ;-)
    >
    > Greetings,
    > Twan
    >
    > At 19:44 06-7-2004, you wrote:
    >> Hello,
    >>
    >> I'm currently in the process of getting
    >> cayenne/struts/velocity/velocitytools to work in jbuilder9. That's a
    >> lot of work but i almost got it right.
    >>
    >> There is one thing i can't figure out:
    >> Tomcat 4.x is saving (serialize) objects which are in session when
    >> tomcats shutsdown. The session data is saved into a file named
    >> "SESSIONS.ser". This file is loaded and session data is recovered
    >> when tomcats starts again.
    >>
    >> There seems to be a conflict with cayenne here. I'm using a
    >> WebApplicationListener to get the datacontext up and running like
    >> described here:
    >> <http://www.objectstyle.org/cayenne/userguide/deploy/web-
    >> application.html>.
    >>
    >> This works fine, but when i shutdown tomcat and restart tomcat a
    >> exception occurs:
    >>
    >> StandardManager[/proj]: Exception loading sessions from persistent
    >> storage
    >> java.lang.ExceptionInInitializerError
    >> at java.io.ObjectStreamClass.hasStaticInitializer(Native
    >> Method)
    >> at
    >> java.io.ObjectStreamClass.computeDefaultSUID(ObjectStreamClass.java:
    >> 1513)
    >> at
    >> java.io.ObjectStreamClass.access$100(ObjectStreamClass.java:45)
    >> at java.io.ObjectStreamClass$1.run(ObjectStreamClass.java:169)
    >> at java.security.AccessController.doPrivileged(Native Method)
    >>
    >> This means that the session data saved to disk can't be loaded. After
    >> this exception occurs very strange things happen, for example cayenne
    >> can't find the cayenne.xml.
    >>
    >> My solution is to delete the "SESSIONS.ser" when tomcat shutsdown,
    >> but thats a bit dirty.
    >>
    >> Does anybody know a solution to this problem? or maybe a way to turn
    >> off the automatic serialisation of session data by tomcat? (just for
    >> development purposes ;-)
    >>
    >> Cheers,
    >> Twan Kogels

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