Content that doesn't change or that doesn't change often should be included using a mechanism which won't try to interpret it.
Specifically, <%@ include file="..." %>, which includes the file in the JSP servlet translation phase (i.e. it happens once),
should be used instead of <jsp:include page="..." />, which includes the page on the file, when the content is being served to the user.
<jsp:include page="header.jsp"> <!-- Non-compliant -->
<%@ include file="header.jsp">