Controller

private void processRequest(HttpServletRequest request, HttpServletResponse response) 
        throws ServletException, IOException {
    
    //set
    //request
    ArrayList<Movie> mlist = mg.searchAllMovies();
    request.setAttribute("mlist", mlist);
    
    //session
    Person p = new Person();
    p.setId(request.getParameter("username"));
    p.setPw(request.getParameter("password"));
    
    HttpSession session = request.getSession();
    session.setAttribute("person", p);
    session.setAttribute("person", null);
    
    //application
    ServletContext application = request.getServletContext();
    application.setAttribute("key3", "global variable");
    
    
    //get
    //request
    String readfromrequest = (String) request.getAttribute("key1");
    String projectRootPath = request.contextPath();
    String currentShortPath = request.getPathInfo();
    switch (path) {
            case "/list":

    //session
    HttpSession session = request.getSession();
    Person p = (Person) session.getAttribute("person");
    
    //application
    String readfromapplication = (String) request.getServletContext().getAttribute("key3");
    
    //get from JSP (Form or URL)
    string u = request.getParameter("username");    
    
}

JSP

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!-- request -->
<!-- get pageContext root path -->
<td><a href="${pageContext.request.contextPath }/HomePage.jsp">Home</a></td>

<!-- get para form request -->
<!--following is ok -->
<c:forEach var="hero" items="${mlist}">
<c:forEach var="hero" items="${param.mlist}">
<c:forEach var="hero" items="${param["mlist"]}">
<c:forEach var="hero" items="${param['mlist']}">

<c:forEach var="hero" items="${requestScope.mlist}">
<c:forEach var="hero" items="${requestScope["mlist"]}">
<c:forEach var="hero" items="${requestScope['mlist']}">

<!-- session -->
<c:if test="${sessionScope.role.equals('Admins')}">
    <li><a href="${pageContext.request.contextPath }/loadData">MyPage</a></li>
</c:if>

<c:url var="addurl" scope="page" value="/views/Admin/SetUpPageCourse.jsp">
    <c:param name="newCourseID" value="${sessionScope.newCourseID }" />
    <c:param name="insert" value="true" />
</c:url>
<a href="${addurl}">Add</a>