Using Facelets along with JSP in a JSF application

I wanted to use Facelets for some pages in an existing JSP/JSF application.
To achieve this I had to perform the following steps:

Download Facelets and copy the jsf-facelets.jar into your WEB-INF/lib directory
If you use maven you can include the following dependency in your pom:

        <dependency>
            <groupId>com.sun.facelets</groupId>
            <artifactId>jsf-facelets</artifactId>
            <version>1.1.14</version>
        </dependency>

Add the FaceletViewHandler to the faces-config.xml file.

<application>
    ...
    <view-handler>
        com.sun.facelets.FaceletViewHandler
    </view-handler>
</application>

Define which pages should be handled by Facelets, i.e. urls ending with '.xhtml'. Add the following snippet to your web.xml:

    <context-param> 
            <param-name>facelets.VIEW_MAPPINGS</param-name> 
            <param-value>*.xhtml</param-value> 
    </context-param>

For a useful debug-screen, you should also add the following snippet to your web.xml:

    <context-param>
        <param-name>facelets.DEVELOPMENT</param-name>
        <param-value>true</param-value>
    </context-param>