Web application cache control

Web application cache control

Ok, I have a Glassfish 4 application server running under the ip say
50.50.50.25 and binded to i.e. app.myhost.com.
When I access to the main page via using the plain IP address 50.50.50.25
the network statistics are
12 requests ❘ 153 KB transferred ❘ 1.92 s (load:
2.32 s, DOMContentLoaded: 2.32 s)
If I open it via the address app.myhost.com the network statistics are
12 requests ❘ 417 KB transferred ❘ 3.53 s (load:
3.73 s, DOMContentLoaded: 3.68 s)
My chrome browser gets half of the requests from cache when the page is
accessed via ip address so it loads faster.
I am just confused how can I make my static content loaded from cache or
force it 304 not modified?