JSF2.2 tags working with *.xhtml but not working with *.html

Question

I am not able to use jsf tags in (*.html), but if I change the page to *.xhtml its working.

help me understand why it is so.

Following is web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    version="2.5">
    <display-name>Project</display-name>
    <session-config>
        <session-timeout>30</session-timeout>
    </session-config>
    <welcome-file-list>
        <welcome-file>index.xhtml</welcome-file>
    </welcome-file-list>
    <servlet>
        <description></description>
        <display-name>FacesServlet</display-name>
        <servlet-name>FacesServlet</servlet-name>
        <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>FacesServlet</servlet-name>
        <url-pattern>*.xhtml</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>FacesServlet</servlet-name>
        <url-pattern>*.html</url-pattern>
    </servlet-mapping>
</web-app>`

Answer 1

include this in your web.xml

<context-param>
    <param-name>javax.faces.DEFAULT_SUFFIX</param-name>
    <param-value>.html</param-value>
</context-param>