671e0429_n___Apache_Software_Foundation__Behavior
[Directive] private [Behavior] 
Public (shared) caches cannot store the response because the response is intended for a single user. If specific response header fields are specified with this value, the restriction applies only to those header fields within the response. If no response header fields are specified, the restriction applies to the entire response.
Server HTTP Transport - Apache CXF Documentation - Apache Software Foundation