Debugging rows gotten by JSTL sql:query

I have some questions written in this article. Sometimes I want to handle the data gotten by sql:query, those can be accessed with the expression like ${row.id}.

I don't know the class using as row in following JSTL. At first, trying to clear what kind of class of row.

<sql:query var="rs" dataSrouce="someDataSource">
  SELECT ID, NAME FROM EMP
</sql:query>

<c:forEach var="row" items="${rs.rows}">
  <c:out value="${row.id}" />:<c:out value="${row.name}" />
</c:forEach>

I'm not sure what kind of class of row. So changing above code to like below.

<c:forEach var="row" items="${rs.rows}">
  <%= pageContext.findAttribute("row").getClass().getName() %>
</c:forEach>

And then, I found that row is a java.util.TreeMap. I'm not sure that sql:query always returns the List of java.util.TreeMap, but it is true in my test environment at least. So, I can access the data included into the row with the following code.

<c:forEach var="row" items="${rs.rows}">
<% 
StringBuffer sb = new StringBuffer();
java.util.TreeMap m = (java.util.TreeMap)pageContext.findAttribute("row");
sb.append(m.get("id")).append(":").append(m.get("name"));
out.print(sb.toString());
%>
</c:forEach>