The OakDefaultComponents inside the Oak builder class was introduced with
OAK-6826 and provides a set of default components. Those components can be overridden by calling the various Oak.with() methods.
There is a problematic OakDefaultComponents singleton INSTANCE used by Jcr. The singleton is mutable and may leak modifications from one Jcr instantiation to another one. More specifically, the SecurityProvider has a couple of configurations that extend ConfigurationBase with multiple setters.