.V
Richard Tomlinson wrote:
I've experienced loss of singleton's under heavy load. We used an object preserver as detailed by Mark Grand in 'Patterns in Java' to register the singleton with a permanently waiting thread.
The other option is to use of statics is to specify the JVM option of -Xnoclassgc to stop class collection.
Regards Richard
-----Original Message----- From: Adolfo Miguelez [mailto:[EMAIL PROTECTED] Sent: Wednesday, August 27, 2003 11:04 AM To: [EMAIL PROTECTED] Subject: Re: Is singleton DAO acceptable? -- Best Practices
Check out this link for some info about this topic. We tested under WAS 5, and its JDK should be 1.3.1 or something like that. Actually the JDK that comes which WAS 5.
http://www.javaworld.com/javaworld/javatips/jw-javatip52.html
It was curious because after a good perfomance, above certain stress load, singleton looks like to dissapear and app begin to throw errors.....
Can not tell you how to solve it since our solution was refactoring code and removing the singleton. Perhaps referencing from somewhere, ServletContext or a struts plugin could help. Maybe someone could help more accuracily,
Adolfo.
From: Mick Wever <[EMAIL PROTECTED]>
Reply-To: "Struts Users Mailing List"
<[EMAIL PROTECTED]>
To: [EMAIL PROTECTED] Subject: Re: Is singleton DAO acceptable? -- Best Practices Date: Wed, 27 Aug 2003 10:43:55 +0200
On Tue, 26 Aug 2003 20:10:07 +0000, Adolfo Miguelez wrote:
Just to share my experience with singletons: under heavy
stress we found
that a singleton class in our framework was garbage
collected. As far as
I
remember, singletons are eligible for that with current
SDKs despite
policy
has changed over times as I read from some document in the web.
They were eligible for GC if its ClassLoader is GCd and
they are not
referenced by any object... or something like that.
Please check for
accuracy.
This is very interesting. Which SDK implementation did you see this behavour?
The single reference to the DAO is actually inside the
DAOFactory not the
DAO itself (hence it is not a traditional Singleton) so
hopefully this
will prevent the scenerio of it being GC'd.
Or will I have to go further and reference it inside a
Struts context as
well? (Eg use the Struts plugin mechanism).
Mick.
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