Why the difference between Tomcat and Tomcat7 regarding servlet mapping and defaults?

Question

With the following configuration:

<servlet-mapping>
    <servlet-name>default</servlet-name>
    <url-pattern>*.css</url-pattern>
</servlet-mapping>
<servlet-mapping>
    <servlet-name>default</servlet-name>
    <url-pattern>*.html</url-pattern>
</servlet-mapping>

then both Tomcat7 and Tomcat6 serves the following URL just fine: http://127.0.0.1:8087/mynet/index.html

However, if I reduce the configuration to just mention the CSS pattern:

<servlet-mapping>
    <servlet-name>default</servlet-name>
    <url-pattern>*.css</url-pattern>
</servlet-mapping>

Then Tomcat6 works, but Tomcat7 fails with: The requested resource () is not available.

Why is there a difference here?

Answer 1

You should not map container's default servlet in your webapp's web.xml. Whatever functional requirement for which you thought that this is the solution, it has definitely to be solved differently.

If you have for example overridden it with a custom front controller servlet on an URL pattern of /, then you should fix that servlet to listen on a more specific URL pattern instead. Use if necessary a filter to "hide" the servlet's specific URL pattern by collecting all static resources in a single folder such as /static or /resources and letting the filter check on that.

See also:

• 404 Error accessing static content when defualt servlet is defined in web.xml
• How to access static resources when using default servlet