Obtener tamaño de array en jstl

<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/functions" prefix="fn" %>
<c:set var="numCategoryProducts" value="${fn:length(categoryProductList)}"/>

<c:out="${numCategoryProducts}"/>