You can use the default-web.xml file to define features such as filters and security constraints that apply to all web applications.
For example, directory listings are disabled by default for added security. To enable directory listings in your domain's default-web.xml file, search for the definition of the servlet whose servlet-name is equal to default, and set the value of the init-param named listings to true. Then restart the server.
<init-param> <param-name>listings</param-name> <param-value>true</param-value> </init-param>
If listings is set to true, you can also determine how directory listings are sorted. Set the value of the init-param named sortedBy to NAME, SIZE, or LAST_MODIFIED. Then restart the server.
<init-param> <param-name>sortedBy</param-name> <param-value>LAST_MODIFIED</param-value> </init-param>
The mime-mapping elements in default-web.xml are global and inherited by all web applications. You can override these mappings or define your own using mime-mapping elements in your web application's web.xml file. For more information about mime-mapping elements, see the Servlet specification.
You can use the Administration Console to edit the default-web.xml file, or edit the file directly using the following steps.
Place the JAR file for the filter, security constraint, or other feature in the domain-dir/lib directory.
Edit the domain-dir/config/default-web.xml file to refer to the JAR file.
To apply your changes, restart GlassFish Server.
See To Restart a Domain.