Spring Avoid cloning empty Annotation array in TypeDescriptor

Rework AnnotatedElementAdapter to avoid cloning the underlying Annotation array if it is empty when getAnnotations() is called.

Additionally, make the class static and add a factory method that returns a singleton instance for null or an empty Annotation arrays.

Comment From: sbrannen

This has been merged into main in 7fa2a289708a4d7d0c8e63433db6f6205ade4229 and revised in 5345a139186f44cbb73f841a1124efe652eea667.

Thanks

Comment From: jhoeller

Backported to 6.1.6, 6.0.19, 5.3.34 as well now since it is a straightforward internal optimization in a hot code path.

Comment From: sbrannen