samples/mobilewebapp/war/WEB-INF/web.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app
    PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
    "http://java.sun.com/dtd/web-app_2_3.dtd">

<web-app>

  <!-- RequestFactory -->
  <servlet>
    <servlet-name>requestFactoryServlet</servlet-name>
    <servlet-class>com.google.web.bindery.requestfactory.server.RequestFactoryServlet</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>requestFactoryServlet</servlet-name>
    <url-pattern>/gwtRequest</url-pattern>
  </servlet-mapping>
  
  <!-- Default page to serve -->
  <welcome-file-list>
    <welcome-file>MobileWebApp.html</welcome-file>
  </welcome-file-list>

  <!-- Set the correct mime-type of media files. -->
  <mime-mapping>
    <extension>ogg</extension>
    <mime-type>audio/ogg</mime-type>
  </mime-mapping>
  <mime-mapping>
    <extension>mp3</extension>
    <mime-type>audio/mp3</mime-type>
  </mime-mapping>
  <mime-mapping>
    <extension>wav</extension>
    <mime-type>audio/wav</mime-type>
  </mime-mapping>
  <mime-mapping>
    <extension>ogv</extension>
    <mime-type>video/ogg</mime-type>
  </mime-mapping>
  <mime-mapping>
    <extension>mp4</extension>
    <mime-type>video/mp4</mime-type>
  </mime-mapping>

</web-app>