DefinitionProvider#getLastModified() would report the last time the underlying configuration (and => definition) has changed. This would help the structures which cache definition providers realise where some entries are stale and need to be purged.

• For the default DefinitionProvider which merely wraps a bean the last mod date would always be equal to the provider's creation date.
• For more dynamic definition providers which are actively connected to some data source (JCR node, YAML file etc) - the last modification date would be connected to last modification date of a corresponding data source.