<%@ taglib prefix="fn" uri="http://java.sun.com/jstl/fn" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jstl/core_rt" %>
<%@ tag body-content="scriptless" %>

<%-- Capture the body evaluation result in a variable --%>
<c:out value="${pageContext.request.servletPath}" />
Before conversion: <c:out value="${bodyRes}"/>
<%-- Convert special characters to character entities --%>
<c:set var="escapedBody" value="${fn:escapeXml(bodyRes)}" />

<%-- Replace "[code]/[/code]" with "<code>/</code>" --%>
<c:set var="convBody" 
  value="${fn:replace(escapedBody, '[code]', '<code>')}" />
<c:set var="convBody" 
  value="${fn:replace(convBody, '[/code]', '</code>')}" />

<%-- Ouput the result --%>
Result: ${convBody}