Hello !!!
J have very simple jsp:
<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-2"%> <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <c:set var="p1" value="test1"/> <c:set var="p2" value="test2"/> <c:out value="${p1}" /> <c:out value="${p2}" /> <c:set var="p3" value="${p1}${p2}"/> <c:out value="---${p3}---${p1}" /> <c:out value="${p1} ${p2}" /> --- it's OK <c:out value="${p1}${p2}" /> --- here is error: The operator + is undefined for the argument type(s) java.lang.Object, java.lang.Object
A bit of google brought me to this one:
https://issues.apache.org/bugzilla/show_bug.cgi?id=46381
Best regards
Wolfgang