JSTL namespace in JSF2.x

Remember to use "http://java.sun.com/jsp/jstl/core" instead of "http://java.sun.com/jstl/core" in JSF2.x

<ui:composition xmlns="http://www.w3.org/1999/xhtml"
    xmlns:ui="http://java.sun.com/jsf/facelets"
    xmlns:h="http://java.sun.com/jsf/html"
    xmlns:f="http://java.sun.com/jsf/core"
    xmlns:c="http://java.sun.com/jsp/jstl/core">    

    ................................

</ui:composition>

Done!!