c：设置变量不打印

Question

我想使用这个RecipeSelected变量值来用于c：set变量和print？但它不打印任何东西。

<%;
     String RecipeSelected = (String)session.getAttribute("Recipe");
     out.println("this is getAttribute from servlet "+RecipeSelected );%>
     <c:set var="id" value="${RecipeSelected }"/>
<%  out.println("using c:out id is : " );%>
<c:out value = '${id}'/>