What's supposed to happen is that when a JSF 2 application is in Development stage, the resources are not cached. Then, when in Production stage, they are cached, for a default of 10 minutes. Mojarra configures the duration with this context param:

<context-param>
<param-name>com.sun.faces.defaultResourceMaxAge</param-name>
<param-value>604800</param-value>
</context-param>

And the project stage is set via this context param:

<context-param>
<param-name>javax.faces.PROJECT_STAGE</param-name>
<param-value>Production</param-value>
</context-param>

Perversely, what I'm seeing is that when using Development stage, the resources are being cached, and when in Production stage they are only being cached when clicking to refresh, but are not cached when clicking outputLinks to GET different pages in the application. Tested by browsing from page to page within ace-showcase. Issue shows up even when not clicking to a different page, but also when repeatedly clicking to show the current page. Setting com.sun.faces.defaultResourceMaxAge or not doesn't seem to affect this immediate caching defect.

Following Deryk's suggestion, I've enabled tomcat's access logging, by uncommenting this from server.xml:

<Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
prefix="localhost_access_log." suffix=".txt" pattern="common" resolveHosts="false"/>

The reason being that Firebug's Net tab seems to be lying about what it's getting from it's cache versus what it's going to the server for.

So, let's go through a few scenarios.

ace-showcase, PROJECT_STAGE=Production, deployed=Yesterday, Browser=Firefox 3.6.13

1. SHIFT-REFRESH of dateTimeEntry.jsf
Firebug: 200 * [Good]
Tomcat: 200 * [Good]

2. Click outputLink to GET dateTimeEntry.jsf
Firebug: 200 * [Bad]
Tomcat: No access except 200 dateTimeEntry.jsf [Good]

3. RERESH of dateTimeEntry.jsf
Firebug: 304 * [Good]
Tomcat: 304 * [Good]

4. Click on outputLink to GET sliderEntry.jsf
Firebug: 200 * [Bad]
Tomcat: No access except 200 sliderEntry.jsf [Good]

ace-showcase, PROJECT_STAGE=Development, deployed=Now, Browser=Firefox 3.6.13

1. SHIFT-REFRESH of dateTimeEntry.jsf
Firebug: 200 * [Good]
Tomcat: 200 * [Good]

2. Click outputLink to GET dateTimeEntry.jsf
Firebug: 304 * [Good]
Tomcat: 304 * [Good]

3. RERESH of dateTimeEntry.jsf
Firebug: 304 * [Good]
Tomcat: 304 * [Good]

4. Click on outputLink to GET sliderEntry.jsf
Firebug: 304 core mandatory, 200 yui_loaded * [Bad-ish]
Tomcat: 304 * [Good]

ace-showcase, PROJECT_STAGE=Production, deployed=Now, Browser=Safari 5.0.5

1. SHIFT-REFRESH of dateTimeEntry.jsf
Tomcat: 200 * [Good]

2. Click outputLink to GET dateTimeEntry.jsf
Tomcat: No access except 200 dateTimeEntry.jsf [Good]

3. RERESH of dateTimeEntry.jsf
Tomcat: 304 * [Good]

4. Click on outputLink to GET sliderEntry.jsf
Tomcat: No access except 200 sliderEntry.jsf and other resources specific to sliderEntry not accessed yet [Good]

ace-showcase, PROJECT_STAGE=Development, deployed=Now, Browser=Safari 5.0.5

1. SHIFT-REFRESH of dateTimeEntry.jsf
Tomcat: 200 * [Good]

2. Click outputLink to GET dateTimeEntry.jsf
Tomcat: 304 * [Good]

3. RERESH of dateTimeEntry.jsf
Tomcat: 304 * [Good]

4. Click on outputLink to GET sliderEntry.jsf
Tomcat: 304 * [Good]

ace-showcase, PROJECT_STAGE=Production, deployed=Now, Browser=IE 7

1. CONTROL-REFRESH of dateTimeEntry.jsf
Tomcat: 200 * [Good]

2. Click outputLink to GET dateTimeEntry.jsf
Tomcat: No access except 200 dateTimeEntry.jsf [Good]

3. RERESH of dateTimeEntry.jsf
Tomcat: 304 * [Good]

4. Click on outputLink to GET sliderEntry.jsf
Tomcat: No access except 200 sliderEntry.jsf and other resources specific to sliderEntry not accessed yet [Good]

ace-showcase, PROJECT_STAGE=Development, deployed=Now, Browser=IE 7

1. CONTROL-REFRESH of dateTimeEntry.jsf
Tomcat: 200 for page resources, 304 for YUI3 loaded resources [Efficient, not necessarily Good]

2. Click outputLink to GET dateTimeEntry.jsf
Tomcat: 304 * [Good]

3. RERESH of dateTimeEntry.jsf
Tomcat: 304 * [Good]

4. Click on outputLink to GET sliderEntry.jsf
Tomcat: 304 * [Good]

So, there doesn't seem to be any problem with the caching, as tested in ace-showcase. The only thing that would indicate a problem, is that Firebug lies about getting resources, which Tomcat shows it is not re-getting.

http://wiki.icefaces.org/display/ICE/JSF+Configuration