Within our AspectJ RuntimeTestWalker, the InstanceOfResidueTestVisitor resolves types via ClassUtils.forName(type.getName()). This can be become quite excessive and is fundamentally unnecessary, since the underlying AspectJ ReferenceType does hold the Class... It's just a bit buried.
The main problem is that a ClassLoader doesn't efficiently resolve classes that it loaded already. As a consequence, it cannot be treated as an efficient cache for class name -> Class. There is quite some lock contention going on there, at least on WebSphere's ClassLoader.
Affects: 3.2.6, 4.0 GA
#16124 CompoundClassLoader.loadClass is trying to load some framework class and comsuming all web container threads.
Fixed through downcasting to AspectJ's ReflectionType and ReflectionBasedReferenceTypeDelegate, obtaining the myClass field there. We only fall back to regular class loading if we encounter any other kind of type.