manasee patel

I have this JSP. The same JSP is to ask for data and display all the previously entered data. This JSP is making a POST request to servlet which put the data coming from parameters of each request in the ServletContext. The first time when I enter data and hit Submit button it works. But for second request there is "HTTP Status 405 - HTTP method GET is not supported by this URL" error. When I override doGet() or redirect the response instead of doing forward, it works.

In JSP the method is POST. i.e every time JSP is making POST request to the servlet. So why there is that 405 error?

The servlet Sample.java:
//necessary imports public class Sample extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { HashMap roomList = null; synchronized(getServletContext()) { roomList = (HashMap) getServletContext().getAttribute("roomList"); if(roomList == null) { roomList = new HashMap(); getServletContext().setAttribute("roomList", roomList); } } String roomName = request.getParameter("name"); String roomDescr = request.getParameter("description"); if(roomName != null && roomName.length() > 0) { synchronized(roomList) { roomList.put(roomName, new ChatRoom(roomName, roomDescr)); } } //response.sendRedirect("http://127.0.0.1:8080/Chat/ChatAdmin.jsp"); RequestDispatcher dispatcher = request.getRequestDispatcher("/ChatAdmin.jsp"); dispatcher.forward(request, response); } /*public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { doPost(request, response); }*/ }
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ChatAdmin.jsp Code Fragment
<form method="POST" action="sample.do"> <% //Java code to extract the data from ServletContext (application) and display it %> </br></br> Name: <input type="text" name="name"/></br> Description: <input type="text" name="description"/></br> <input type="submit" value="Submit"/>
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web.xml:
<servlet> <servlet-name>sample</servlet-name> <servlet-class>Sample</servlet-class> </servlet> <servlet-mapping> <servlet-name>sample</servlet-name> <url-pattern>/sample.do</url-pattern> </servlet-mapping>

I think I found the answer. It's here.

A member is marked static so that it will behave consistent regardless of the instance. Any how we can't instantiate interface. The variable of interface will be meaningful only when some class implements it. And that class can be instantiated. So why to make it static?

What if the classes implementing the interface want to change the value of interface variable? Or why should not they want? As in abstract class the subclass can change the values of variables declared in the abstract superclass. Why is it problem for interfaces?

Thank You. But then from where i.e. from which directory will I compile my j2ee classes? I don't know glass fish server. When I installed it (what I considered j2ee but found to be a server) there was only a directory named glassfishv3 and in that there is no j2ee. Yes, in start menu there are options but all for that server.

I want to download j2ee, the latest. I don't know is it 1.5 or 1.6? I want to compile my servlet, jdbc, ... files. I have tomcat configured and it is displaying the welcome page. So I want the link to download the thing required to compile j2ee files. What is it called? j2ee runtime? j2ee SDK? I already have downloaded java_ee_sdk-6-web-windows. But I guess it has only that glassfish server and not the thing required to compile j2ee files. I don't want any server or IDE coming along with it. I already have many of those plus my internet connection is slow. So what should I download?