Accessing a Session Bean via a servlet

[Peter Matthews]

Hi All,

I'm encountering a problem when trying to access a session bean via a servlet - I'm getting the following security exception aswell as Null Pointer exception:

java.security.AccessControlException: access denied (java.lang.RuntimePermission exitVM)
at java.security.AccessControlContext.checkPermission(AccessControlContext.java:264)
at java.security.AccessController.checkPermission(AccessController.java:427)
at java.lang.SecurityManager.checkPermission(SecurityManager.java:532)
at java.lang.SecurityManager.checkExit(SecurityManager.java:744)
at com.sun.enterprise.J2EESecurityManager.checkExit(J2EESecurityManager.java:83)
at java.lang.Runtime.exit(Runtime.java:88)
at java.lang.System.exit(System.java:868)
at searchservlet.SearchServlet.processRequest(SearchServlet.java:45)
at searchservlet.SearchServlet.doGet(SearchServlet.java:87)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:747)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:860)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.apache.catalina.security.SecurityUtil$1.run(SecurityUtil.java:249)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAsPrivileged(Subject.java:517)
at org.apache.catalina.security.SecurityUtil.execute(SecurityUtil.java:282)
at org.apache.catalina.security.SecurityUtil.doAsPrivilege(SecurityUtil.java:165)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:257)
at org.apache.catalina.core.ApplicationFilterChain.access$000(ApplicationFilterChain.java:55)
at org.apache.catalina.core.ApplicationFilterChain$1.run(ApplicationFilterChain.java:161)
at java.security.AccessController.doPrivileged(Native Method)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:263)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:551)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:225)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:173)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:551)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:161)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:551)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:132)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:551)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:933)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:185)
at com.sun.enterprise.web.connector.grizzly.ProcessorTask.process(ProcessorTask.java:653)
at com.sun.enterprise.web.connector.grizzly.ProcessorTask.process(ProcessorTask.java:534)
at com.sun.enterprise.web.connector.grizzly.ProcessorTask.doTask(ProcessorTask.java:403)
at com.sun.enterprise.web.connector.grizzly.WorkerThread.run(WorkerThread.java:55)
|#]

[#|2006-04-15T10:22:08.229+0100|SEVERE|sun-appserver-pe8.1_02|javax.enterprise.system.container.web|_ThreadID=13;|StandardWrapperValve[SearchServlet]: Servlet.service() for servlet SearchServlet threw exception
java.lang.NullPointerException
at searchservlet.SearchServlet.processRequest(SearchServlet.java:56)
at searchservlet.SearchServlet.doGet(SearchServlet.java:87)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:747)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:860)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.apache.catalina.security.SecurityUtil$1.run(SecurityUtil.java:249)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAsPrivileged(Subject.java:517)
at org.apache.catalina.security.SecurityUtil.execute(SecurityUtil.java:282)
at org.apache.catalina.security.SecurityUtil.doAsPrivilege(SecurityUtil.java:165)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:257)
at org.apache.catalina.core.ApplicationFilterChain.access$000(ApplicationFilterChain.java:55)
at org.apache.catalina.core.ApplicationFilterChain$1.run(ApplicationFilterChain.java:161)
at java.security.AccessController.doPrivileged(Native Method)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:263)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:551)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:225)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:173)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:551)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:161)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:551)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:132)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:551)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:933)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:185)
at com.sun.enterprise.web.connector.grizzly.ProcessorTask.process(ProcessorTask.java:653)
at com.sun.enterprise.web.connector.grizzly.ProcessorTask.process(ProcessorTask.java:534)
at com.sun.enterprise.web.connector.grizzly.ProcessorTask.doTask(ProcessorTask.java:403)
at com.sun.enterprise.web.connector.grizzly.WorkerThread.run(WorkerThread.java:55)
|#]

I have used the session bean via a standard client, and all worked fine, so I'm not sure why also I have a Null Pointer exception. I am novice in both servlets and session beans, so any help would be very much appreciated.

Thanks, Peter

Here is my servlet code if it helps:

/*
 * SearchServlet.java
 *
 * Created on 14 April 2006, 19:47
 */
 
package searchservlet;
 
import java.io.*;
import java.util.ArrayList;
import java.util.Iterator;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.rmi.PortableRemoteObject;
 
import javax.servlet.*;
import javax.servlet.http.*;
 
/**
 *
 * @author Peter Matthews
 * @version
 */
public class SearchServlet extends HttpServlet {
    search.SearchRemote myHouse;
    
    /** Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods.
     * @param request servlet request
     * @param response servlet response
     */
    
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
         try {
            
            Context initial = new InitialContext();
            Object objref = initial.lookup("ejb/SearchBean");
            
            search.SearchRemoteHome home =
                    (search.SearchRemoteHome) PortableRemoteObject.narrow(objref,
                    search.SearchRemoteHome.class);
            
            search.SearchRemote myHouse = home.create();
           
        } catch (Exception ex) {
            System.err.println("Caught an exception:");
            ex.printStackTrace();
        }
        
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        ArrayList houseList;
        Integer bedrooms = Integer.valueOf(request.getParameter("select2"));
        houseList = myHouse.SearchByRooms(bedrooms);
        Iterator i = houseList.iterator();
 
        while (i.hasNext()) {
            Object details = (Object) i.next();
 
            out.println(details.toString());
        }
        
        /* TODO output your page here
        out.println("<html>");
        out.println("<head>");
        out.println("<title>Servlet SearchServlet</title>");
        out.println("</head>");
        out.println("<body>");
        out.println("<h1>Servlet SearchServlet at " + request.getContextPath () + "</h1>");
        out.println("</body>");
        out.println("</html>");
         */
        out.close();
    }
    
 
    
    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /** Handles the HTTP <code>GET</code> method.
     * @param request servlet request
     * @param response servlet response
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }
    
    /** Handles the HTTP <code>POST</code> method.
     * @param request servlet request
     * @param response servlet response
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }
    
    /** Returns a short description of the servlet.
     */
    public String getServletInfo() {
        return "Short description";
    }
    // </editor-fold>
    
}
    

[David O'Meara]

The main problem is caused by the NullPointer so you should try to solve that. The other (SecurityException) problem is caused by some code somwhere trying to call System.exit() and being blocked. You should also chase this down and remove it. It may even be causing the NPE too.

[Peter Matthews]

Thanks David - taking the System.out() out did the trick!

[Peter Matthews]

I meant System.exit() - these late nights are catching up with me!