Major Description
As part of improving the API for LOG4J2-653, and as mentioned on the mailing lists in the past, it would be great to have some basic annotations for automatic validation of plugin configurations. For instance, an annotation to mark a parameter/field as required, or have a min/max size, etc.
Ideally, this API should be somewhat flexible like the Java EE bean validation API. However, this API should be far more lightweight due to its limited need for equivalent functionality. It should probably resemble the plugin visitors API, and may in fact be implemented as a plugin visitor.