java - JSTL Reading if session value is set not working properly -

i'm making testing , have faced strange problem, i'm setting session on servlet:

sessions.setattribute("logged_in", "true"); 

this code on jstl page, want check if session name "logged_in" set

<c:choose>     <c:when test="${not empty sessionscope.logged_in}">         <a href="/logout">logout</a>     </c:when>     <c:otherwise>         <a href="/login">login</a>     </c:otherwise> </c:choose> 

but when check website, outputs:

<a href="/logout">logout</a> <a href="/login">login</a> 

it should output login or logout, not both. idea might wrong here?

look's tags not executed server.

have added jstljars in library , added <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> in jsp?