<c:set var="Solution" value="Выход"/>
          <LI><a href="<%=request.getContextPath()%>/LogoutUser">${Solution}</a>

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * Servlet implementation class LogoutServlet
 */
@WebServlet(
        name = "LogoutUser",
        description = "Разрыв сессии пользователя",
        urlPatterns = "/LogoutUser"
)
public class LogoutUser extends HttpServlet {
    private static final long serialVersionUID = 1L;

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html");
        Cookie[] cookies = request.getCookies();
        if(cookies != null){
            for(Cookie cookie : cookies){
                if(cookie.getName().equals("JSESSIONID")){
                    System.out.println("JSESSIONID="+cookie.getValue());
                    break;
                }
            }
        }
        //invalidate the session if exists
        HttpSession session = request.getSession(false);
        System.out.println("User="+session.getAttribute("user"));
        if(session != null){
            session.invalidate();
        }
        response.sendRedirect("login.jsp");
    }

}

HTTP Status 405 - HTTP method GET is not supported by this URL

type Status report

message HTTP method GET is not supported by this URL

description The specified HTTP method is not allowed for the requested resource.