f887361f_ing_Configuring___Eclipsepedia__Cache_Annotation_Attributes_Description
[Attribute] expiry [Default] no expiry [Required?] Optional [Description] 
The int value to enable the expiration of the cached instance after a fixed period of time (milliseconds). Queries executed against the cache after this will be forced back to the database for a refreshed copy.
EclipseLink/UserGuide/JPA/Basic JPA Development/Caching/Configuring - Eclipsepedia