Hi all,
we are migrating an application from a very old version of OWB to the current
one and are experiencing huge memory problems.
They are caused by the following pattern, that is widely used in the
application:
@ApplicationScoped
public class MyService {
@Inject
@Current // custom qualifier
private Provider<User> currentUserProvider;
public void doSomething withCurrentUser() {
User currentUser = currentUserProvider.get();
…
}
}
Unfortunately in the Provider (in InstanceImpl) the created objects are stored
together with their CreationalContext in a map. I guess, that is required to
correctly implement Instance#destroy.
However that leads to the situation, that every user is stored forever in that
map and will never be removed, which leads to our memory problems.
I know that the correct solution would be to Instance#destroy the User after
usage. And we probably will do that in the migration project.
Although I don’t consider this observed behavior a bug, I wonder if we could
deal with that situation in a more intelligent way. I can think of three
possible ways:
1. When the injection point is of type Provider<T> (and not Instance<T>) we
should not store the creational context at all, because there is no way, that
it could ever be used.
2. The map where the creational contexts are stored could be a WeakHashMap.
When the created object is gone there is no way to call Instance#destroy, so we
don’t need the creational context.
3. We could detect, if a bean has any destruction logic at all, if not, we
should not store the creational context, because Instance#destroy is a NoOp
anyway
WDYT? If you are fine, I would implement one of the routes. Which one do you
prefer?
Cheers,
Arne
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