CopyOnWriteArraySet - JBCL-20

[adrian.brock]

https://jira.jboss.org/jira/browse/JBCL-20

I was seeing a lot of time spent in CopyOnWriteArraySet when checking
blacklisting in the classloader.

The reason is that the class isn't intended for large data sets,
in fact it uses a CopyOnWriteArrayList underneath and does linear traversals.

I've changed the usage to a ConcurrentHashMap where I effectively
only use the key side.

It might be an idea to add a ConcurrentSet implementation to common-core
that is implemented on top of a ConcurrentHashMap?

[adrian.brock]

Incidently the reason the blacklist is so large is because we are still using the
old annotation scanning (which has the problem I reported a couple of months ago).

i.e. if you have an unpacked subdeployment, it thinks
subdeployment.jar/org/jboss/whatever/Some.class
might be a class.

When it fails to the load the class, it fills ups the blacklist.

This is besides it wasting time scanning things it doesn't need to
and creating lots of unnecessary ClassNotFoundExceptions.

[alesj]

It might be an idea to add a ConcurrentSet implementation to common-core
that is implemented on top of a ConcurrentHashMap?

OK, I'll add this to the common-core.
Any other collection API we can/should add?

[alesj]

Incidently the reason the blacklist is so large is because we are still using the
old annotation scanning (which has the problem I reported a couple of months ago).

This should all go away once we switch to my annotation scanning. ;-)
It should be soon, since I saw Emanuel finished the Metadata changes required to have more optimized lookup actions.