What's the point of package annotations?

Question

I understand the purpose of class annotations, thanks to How and where are Annotations used in Java?. What is the purpose of package annotations, as described in this blog p

Answer 1

JAXB for example allows most annotations that are normally used on a type to be equally well applied to a package. The meaning in that case would be to specify the default for all classes in that package.

For example, if you want all properties of all classes in a package that are exposed via getter/setters to be mapped in XML you could specify @XmlAccessorType(XMLAccessType.PROPERTY) on each class or simply specify it on the package.