Static static resources going through DispatcherServlet - spring

Question

In my Spring webapp I have annotated my dispatcher servlet like this:
<tx:annotation-driven />
<mvc:annotation-driven />
<context:annotation-config />
<context:component-scan base-package="com.myapp.package.controller" />
<mvc:resources location="/css/" mapping="/css/**" />
<mvc:resources location="/script/" mapping="/script/**" />
<mvc:resources location="/img/" mapping="/img/**" />
<mvc:resources location="/fonts/" mapping="/fonts/**" />
<!-- Uso de Tiles -->
<bean id="tilesConfigurer" class="org.springframework.web.servlet.view.tiles2.TilesConfigurer">
<property name="definitions">
<list>
<value>/WEB-INF/tiles-defs.xml</value>
</list>
</property>
</bean>
<bean id="viewResolver" class="org.springframework.web.servlet.view.UrlBasedViewResolver">
<property name="viewClass" value="org.springframework.web.servlet.view.tiles2.TilesView" />
</bean>
Now by activating spring's debug mode on log4j.properties, I've checked that every resource (even static resources) goes through DispatcherServlet, which I don't even know if it's expected behavior. The fact is, by debugging the processRequest method I've checked that this method is somehow causing high memory consumption on serving each webpage, my guess being that every static resource is being held in memory by this method.
This is the log output for a static resource such as jquery script library:
14:14:23,569 DEBUG RequestMappingHandlerMapping:220 - Looking up handler method for path /script/jquery/jquery-1.9.1.min.js
14:14:23,575 DEBUG RequestMappingHandlerMapping:230 - Did not find handler method for [/script/jquery/jquery-1.9.1.min.js]
14:14:23,576 DEBUG SimpleUrlHandlerMapping:169 - Matching patterns for request [/script/jquery/jquery-1.9.1.min.js] are [/script/**]
14:14:23,576 DEBUG SimpleUrlHandlerMapping:194 - URI Template variables for request [/script/jquery/jquery-1.9.1.min.js] are {}
14:14:23,576 DEBUG SimpleUrlHandlerMapping:124 - Mapping [/script/jquery/jquery-1.9.1.min.js] to HandlerExecutionChain with handler [org.springframework.web.servlet.resource.ResourceHttpRequestHandler#101f75b5] and 1 interceptor
14:14:23,576 DEBUG DispatcherServlet:912 - Last-Modified value for [/myapp/script/jquery/jquery-1.9.1.min.js] is: -1
14:14:23,576 DEBUG ResourceHttpRequestHandler:173 - Trying relative path [jquery/jquery-1.9.1.min.js] against base location: ServletContext resource [/script/]
14:14:23,577 DEBUG ResourceHttpRequestHandler:178 - Found matching resource: ServletContext resource [/script/jquery/jquery-1.9.1.min.js]
14:14:23,577 DEBUG ResourceHttpRequestHandler:132 - Determined media type 'application/javascript' for ServletContext resource [/script/jquery/jquery-1.9.1.min.js]
As far as I can tell it's properly identifying it as a static resource.
Is my configuration right? Shouldn't static resources be served directly instead of going throuhg Dispatcher Servlet? Could it be that every resource is being kept in memory on serving it to the response?

Answer 1

<mvc:resources location="/css/" mapping="/css/**" />
means that the dispatcher servlet will, indeed, serve static resources located in /css for any URL starting with /css/. This is what allows serving static resources from the classpath, for example, instead of serving them from static files in the webapp.
If you don't want the Spring servlet to serve static resources, the do as the documentation indicates:
<mvc:default-servlet-handler/>

Answer 2

If you've done configured something with Spring, Spring will handle it.
When you provide a config with this element
<mvc:resources location="/css/" mapping="/css/**" />
Spring registers a SimpleUrlHandlerMapping bean with a mapping between the specified mapping and a ResourceHttpRequestHandler for the location.
The DispatcherServlet registers all HandlerMapping beans it finds in the ApplicationContext. One of these will be the SimpleUrlHandlerMapping above. If a request arrives which the SimpleUrlHandlerMapping can handle, the DispatcherServlet will use it. The SimpleUrlHandlerMapping will then delegate to the appropriate ResourceHttpRequestHandler which will serve the static resource.
Could it be that every resource is being kept in memory on serving it
to the response?
No, the ResourceHttpRequestHandler does not cache the content of the resource.