Spring Security Cache Annotation Lookups

Several Security components use SecurityAnnotationScanners to look for annotations and apply Security's expression template support and enforce its uniqueness constraints.

Given that this is used by a number of method interceptors and AOT hints, it would be nice if the found merged annotations were cached. Indeed, the JavaDoc encourages this:

/**
  * Since the process of synthesizing an annotation can be expensive, it's recommended to
  * cache the synthesized annotation to prevent multiple computations.
  */