GuardedBy
The field or method to which this annotation is applied can only be accessed
when holding a particular lock, which may be a built-in (synchronization)
lock, or may be an explicit java.util.concurrent.Lock.
When this annotation is applied to a method, it indicates that if this method
is overridden in a subclass, the overriding method should invoke this method
(through method invocation on super).
This qualifier is applied to an annotation to denote that the annotation
defines a default type qualifier that is visible within the scope of the
element it is applied to.