JSF web.xml error

I have a problem on the first line of my web.xml , on web-app . Below is the body of 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 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns="http://xmlns.jcp.org/xml/ns/javaee"xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"id="WebApp_ID" version="3.1">



<display-name>Bootstrap</display-name>
    <welcome-file-list>
        <welcome-file>index.jsf</welcome-file>
    </welcome-file-list>
    <servlet>
        <servlet-name>Faces Servlet</servlet-name>
        <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>Faces Servlet</servlet-name>
        <url-pattern>*.jsf</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>Faces Servlet</servlet-name>
        <url-pattern>/faces/*</url-pattern>
    </servlet-mapping>
    <context-param>
        <param-name>primefaces.THEME</param-name>
        <param-value>bootstrap</param-value>
    </context-param>
    <context-param>
        <param-name>javax.faces.STATE_SAVING_METHOD</param-name>
        <param-value>client</param-value>
    </context-param>
     <context-param>
  <param-name>facelets.DEVELOPMENT</param-name>
  <param-value>true</param-value>
 </context-param>
  <param-name>com.sun.faces.verifyObjects</param-name>
  <param-value>true</param-value>
 </context-param>
 <context-param>
  <param-name>org.ajax4jsf.SKIN</param-name>
  <param-value>classic</param-value>
 </context-param>
 <filter>
  <display-name>Ajax4jsf Filter</display-name>
  <filter-name>ajax4jsf</filter-name>
  <filter-class>org.ajax4jsf.Filter</filter-class>
 </filter>
 <filter-mapping>
  <filter-name>ajax4jsf</filter-name>
  <servlet-name>Faces Servlet</servlet-name>
  <dispatcher>REQUEST</dispatcher>
  <dispatcher>FORWARD</dispatcher>
  <dispatcher>INCLUDE</dispatcher>
 </filter-mapping>
    <context-param>
        <param-name>javax.servlet.jsp.jstl.fmt.localizationContext</param-name>
        <param-value>resources.application</param-value>
    </context-param>
</web-app>