CacheControl issues inside REST web services

I am using this piece of code inside my webservice (Jersey REST Webservice calls) to speed up my application by providing a cache

         CacheControl cc = new CacheControl();
         cc.setMaxAge(300000);
         cc.setPrivate(true);
         httpresponse.addHeader("Cache-Control", cc.toString());

      

        
        
        
      

    

But I see that after a while, the return respawn is empty.

(database interleaving occurs)

Could you please let me know what could be causing this?