diff --git a/jsf/src/main/webapp/el_intro.xhtml b/jsf/src/main/webapp/el_intro.xhtml
index acf84752af..4ca5e44703 100644
--- a/jsf/src/main/webapp/el_intro.xhtml
+++ b/jsf/src/main/webapp/el_intro.xhtml
@@ -2,6 +2,7 @@
 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
 <html xmlns="http://www.w3.org/1999/xhtml"
       xmlns:h="http://java.sun.com/jsf/html"
+      xmlns:c="http://java.sun.com/jsp/jstl/core"
       xmlns:f="http://java.sun.com/jsf/core">
     <h:head>
         <title>Baeldung | The EL Intro</title>
