Instead of
<% session.setAttribute("emailvalue",request.getParameter("<%=request.getQueryString() %>"));String str=(String)session.getAttribute("emailvalue"); %>
store the value obtained from request.getQueryString() in another variable. The code you have has a jsp systemout tag <%=...%> inside another jsp java tag <%...%> which is not supported by the jsp compiler.
Instead make the code simpler to make it work like the following
<% String queryString = request.getQueryString(); session.setAttribute("emailvalue",queryString ); String str=(String)session.getAttribute("emailvalue");%>