autoscan | Autoscan replaces the default Plex | Media library

It's on-demand bean injection.

Spring looks for all the configuration classes, from these classes it starts scanning packages and XML files to create beans.

While scanning if it founds that a particular bean has to be created then it will try to create that bean, while creating it may encounter that this bean is depending on other beans, now it will try to create other dependents beans. Once dependent beans are created they can now be autowired either using Field injection or construction injection. While creating it needs to also consider lazy and optional beans. Spring follows the bean creation path as they require, if you give package name in the scanner then this can create a cycle as well.

For XML things become more complex, for example, a XML bean might be depending on package scanner based and vice-versa then spring has to go through each XML file to see how to create that bean.