there is no gc on static objects. static objects(methods,fields, or classes) are created once on startup and there is only one instance of the method or field ever created that all requestors to your class will use. But with Tomcat I do believe that if you have the same class in 2 different contexts, that it will load two separate instances of your bean due to the different class loaders.
This also means that if you are writing to the static fields on the first(or any) call, make sure to synchronize the write, in case 2 calls occur at the same time.
Charlie
-----Original Message-----
From: Jeff Kilbride [mailto:[EMAIL PROTECTED]]
Sent: Thursday, May 17, 2001 8:56 PM
To: [EMAIL PROTECTED]
Subject: Re: Bean Choices (code question)
Yeah, I know, but it's tempting to write all the methods as "public static".
Then I don't have to create the object at all, but I don't know the affects
on garbage collection.
--jeff
----- Original Message -----
From: "Ross Dyson" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, May 17, 2001 5:24 PM
Subject: RE: Bean Choices (code question)
> If you make the bean class have a private constructor and a static
reference
> to an instance of its own class, then there will always be a strong
> reference from the class itself to the instance of the class. (The first
> call to bean.getInstance() instantiates the private static member variable
> which is your singleton instance of your bean, the contructor does the db
> work etc.)
>
> Therefore, it won't get gc'd.
>
> That's the way I do my classes that do that kind of stuff, anyway.
>
> -----Original Message-----
> From: Jeff Kilbride [mailto:[EMAIL PROTECTED]]
> Sent: Friday, 18 May 2001 9:35 AM
> To: [EMAIL PROTECTED]
> Subject: Bean Choices (code question)
>
>
> I'm sorry if this is a little off-topic, since it is more about java code,
> but I thought Tomcat users would be interested/knowledgeable about the way
> beans work.
>
> I have a lot of informational beans that hold static reference data (think
> ISO codes, State abbreviations, etc...) With these types of beans, I have
> the choice of instantiating a singleton object reference to the bean and
> accessing the methods through the object, or making all the methods
"public
> static" so I can access them via BeanName.method(). For the former, the
bean
> does all of it's initialization and database access in it's constructor
and
> my JSP's have something like the following at the top:
>
> <%!
> private static BeanName bean = BeanName.getInstance();
> %>
>
> For the latter, the bean does all of it's initialization and database
access
> in a static block:
>
> static {
> // bean initialization and DB access
> }
>
> and my JSPs reference the static methods:
>
> <%= BeanName.method() %>
>
> My question concerns the way beans with all "public static" methods are
> instantiated and garbage collected. Because these beans hold unchanging
> reference info, I only want the data loaded from the database once the
first
> time the bean is referenced. For beans with all "public static" methods,
> since there are no object references to them, when are they garbage
> collected? Is it possible that the bean will be unloaded and the code in
my
> static block will be re-run when the bean is next referenced? Or do these
> all static objects somehow stick around forever? For the singleton, I know
> the object will last as long as the JSP is loaded, because there is a
> definite object reference to the singleton. I'm a little unclear as to
what
> happens with a bean that has all "public static" methods, though.
>
> Can anyone shed some light on this?
>
> Thanks,
> --jeff
>
>
