In JSF 1.2 you need to provide the below configuration in faces-config.xml in order to use Facelets. If you are using JSP and not using the Spring Faces components, you do not need to add anything to your faces-config.xml

<faces-config>
    <application>
        <!-- Enables Facelets -->
        <view-handler>com.sun.facelets.FaceletViewHandler</view-handler>  
    </application>
</faces-config>
        

In JSF 2.0 your faces-config.xml should use the faces-config schema version 2.0. Also you should remove the FaceletViewHandler shown above (if it is present) as Facelets are now the default rendering technology in JSF 2.

<?xml version='1.0' encoding='UTF-8'?>
<faces-config xmlns="http://java.sun.com/xml/ns/javaee"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-facesconfig_2_0.xsd"
        version="2.0">

</faces-config>