On May 27, 2008, at 3:50 PM, Andrew Thorburn wrote:
Yes, that helps a lot. It's not the answer I wanted, but it does answer the question :).
I guess that means I'll have to play around and see what can be done.
How do separate classloaders work with statics (fields, etc). e.g. If I have a class A with static field B in the WAR, and again in the EJB jar, will I have two instances of that field, such that the WAR has one (because it has it's own separate classloader), and the EJB will have another? If so, then that's a problem.
With normal parent-first classloader delegation, only one copy of the class will be loaded, the one in the ejb jar. If you turn on inverse-classloading in the war, then you will get two copies: one in the ejb jar visible to the ejbs, and one in the war, visible to the web app. IMO it is almost never appropriate to turn on inverse-classloading. I didn't discuss this detail in my first reply.
I don't know much about Java Beans or Enterprise Java Beans, so this might be a bit silly, but: Can I put the MDB in the WAR? Or does it *have to* have it's own JAR?
An mdb has to be in an ejb jar. (or a jar accessible to the ejb apps classloader, such as in a jar in an ear lib directory). Since the web app/war has a separate classloader that is a child of the ear classloader, there's no way you will be able to get the mdb visible to an ejb app if it is in the war.
I guess I should mention that I think openejb standalone has a mode in which you can do something like what you seem to want to do, but it is not standard javaee. I don't know too much about it.
hope this helps
On Tue, May 27, 2008 at 6:03 PM, David Jencks <firstname.lastname@example.org
I'm not sure I've understood clearly what problem you are having. Maybe if I explain the classloader structure your app has and what I think you need to do it will help.
On May 26, 2008, at 6:28 PM, Andrew Thorburn wrote:
Ok, it now works. Well, kinda.
I think I must have originally also had a lib directory directly inside the EAR, as well as in the WAR, which was what was confusing Geronimo. Removed that, and my bean didn't start. Removed the (small but important) bits of code that relied on that, and everything works. Except it doesn't do logging anymore for my MDB. Works fine everywhere else.
Apologies for not having the faintest idea what my problem was, but there we go. I now have a new problem, however: How do I reference the stuff in the WAR from my MDB JAR? I'm sure I saw information on this somewhere, but I closed it because I thought I had a different problem :(. I can't duplicate the JARS, as I'm sure that'll cause a vast multitude of problems. I really just want to be able to reference them easily, so that I don't have to worry about this when coding my application. In fact, it's going to be very necessary to communicate between the WAR and the MDB for it to be of any use at all (AJAX stuff communicating between browser and database via Java app). Basically need the WAR to be processed first, and then have the MDB JAR processed, so that I can then reference all the classes in the WAR.
Is this possible? If not, what's the best alternative? Can I chuck my MDB into the WAR? I'd be very surprised if I could do that. And I don't know if that would solve any of my issues anyway...
The exact location of the classfiles doesn't matter, just so long as it all works...
Feh. This is starting to do my head in. Won't be posting again for nearly 24 hours (I only work part-time).
For an ear based application with no javaee app clients, there is one "base" classloader that includes all the ejb jars, all the rars, and all the jars in the lib directory.
Then for each war inside the ear, there is a separate classloader that is a child of the ear classloader that contains the jars in WEB-INF/lib and the classes in WEB-INF/classes. Since this is a child of the ear classloader, all the code in the war can see the classes in the ear (ejb, connector, and lib). Also, since these war classloaders are children of the ear, nothing in an ejb, connector or lib jar can see anything in any war classloader.
I think what you need to do is put any classes that need to be accessible to both the ejb app (such as your mdb) and the war(s) in either the ejb jar or in a jar in the ear's lib directory. Putting any such class anywhere in any war file will definitely prevent it being accessible from the ejb application.
Hope this relates to what you are asking about :-)
Anyway, thanks again,