Sample of web.xml

<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> 

     <!-- //// -->
     <!-- ZK -->
	<listener>
		<description>ZK listener for cleanup when a session is destroyed</description>
		<listener-class>org.zkoss.zk.ui.http.HttpSessionListener</listener-class>
	</listener>
	<servlet>
		<description>ZK loader for evaluating ZUML pages</description>
		<servlet-name>zkLoader</servlet-name>
		<servlet-class>org.zkoss.zk.ui.http.DHtmlLayoutServlet</servlet-class>
		<!--
			Must. Specifies URI of the update engine (DHtmlUpdateServlet). It
			must be the same as <url-pattern> for the update engine.
		-->
		<init-param>
			<param-name>update-uri</param-name>
			<param-value>/zkau</param-value>
		</init-param>
		<load-on-startup>1</load-on-startup><!-- MUST -->
	</servlet>
	<servlet-mapping>
		<servlet-name>zkLoader</servlet-name>
		<url-pattern>*.zul</url-pattern>
	</servlet-mapping>
	<servlet-mapping>
		<servlet-name>zkLoader</servlet-name>
		<url-pattern>*.zhtml</url-pattern>
	</servlet-mapping>
	<servlet>
		<description>The asynchronous update engine for ZK</description>
		<servlet-name>auEngine</servlet-name>
		<servlet-class>org.zkoss.zk.au.http.DHtmlUpdateServlet</servlet-class>
	</servlet>
	<servlet-mapping>
		<servlet-name>auEngine</servlet-name>
		<url-pattern>/zkau/*</url-pattern>
	</servlet-mapping>
     <!-- //// -->

     <!-- MIME mapping -->
	<mime-mapping>
		<extension>gif</extension>
		<mime-type>image/gif</mime-type>
	</mime-mapping>
	<mime-mapping>
		<extension>html</extension>
		<mime-type>text/html</mime-type>
	</mime-mapping>
	<mime-mapping>
		<extension>htm</extension>
		<mime-type>text/html</mime-type>
	</mime-mapping>
	<mime-mapping>
		<extension>jad</extension>
		<mime-type>text/vnd.sun.j2me.app-descriptor</mime-type>
	</mime-mapping>
	<mime-mapping>
		<extension>jpeg</extension>
		<mime-type>image/jpeg</mime-type>
	</mime-mapping>
	<mime-mapping>
		<extension>jpg</extension>
		<mime-type>image/jpeg</mime-type>
	</mime-mapping>
	<mime-mapping>
		<extension>js</extension>
		<mime-type>application/x-javascript</mime-type>
	</mime-mapping>
	<mime-mapping>
		<extension>png</extension>
		<mime-type>image/png</mime-type>
	</mime-mapping>
	<mime-mapping>
		<extension>txt</extension>
		<mime-type>text/plain</mime-type>
	</mime-mapping>
	<mime-mapping>
		<extension>xml</extension>
		<mime-type>text/xml</mime-type>
	</mime-mapping>
	<mime-mapping>
		<extension>zhtml</extension>
		<mime-type>text/html</mime-type>
	</mime-mapping>
	<mime-mapping>
		<extension>zul</extension>
		<mime-type>text/html</mime-type>
	</mime-mapping>
	<welcome-file-list>
		<welcome-file>index.zul</welcome-file>
		<welcome-file>index.zhtml</welcome-file>
		<welcome-file>index.html</welcome-file>
		<welcome-file>index.htm</welcome-file>
	</welcome-file-list>
</web-app>