JSTL pointers?

Here's one that can be useful. I created a HashMap of HashMaps (formFields). Each HashMap in the HashMap contains some data about a formfield. I noticed that depending on how I access the inner HashMaps, it either acts like call by value or call by reference. This is under Sun Appserver 8.1.

  <c:forEach var="field" items="${formFields}">
 <%-- this creates a copy --%>
       <c:set var="currentField" value="${field.value}"/>
       <%-- this creates a pointer: --%>
 <c:set var="currentField" value="${formFields[field.key]}"/>
 </c:forEach>