Need help using HashMap in a Message Driven App

Question

Hi ppl,
Im new to the forum and to Java as well. I do have some basic Java knowledge though. Anyway Im a 4th Year student and I got an assignment to build a message server that uses map messages. I fiddled around with the NewsApp example provided at NetBeans ( http://www.netbeans.org/kb/55/ejb30.html)and tried modifying it to set up to use a HashMap but no success :(
Here are some snippets,
NewsEntity.java
package ejb;
import java.io.Serializable;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
* Entity class NewsEntity
* @author Kiran
@Entity
public class NewsEntity implements Serializable {
    private String title;
    private String body;
    private HashMap hm = new HashMap();
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    /** Creates a new instance of NewsEntity */
    public NewsEntity() {
    public Long getId() {
        return this.id;
    public void setId(Long id) {
        this.id = id;
    @Override
    public int hashCode() {
        int hash = 0;
        hash += (this.getId() != null ? this.getId().hashCode() : 0);
        return hash;
    @Override
    public boolean equals(Object object) {
        // TODO: Warning - this method won't work in the case the id fields are not set
        if (!(object instanceof NewsEntity)) {
            return false;
        NewsEntity other = (NewsEntity)object;
        if (this.getId() != other.getId() && (this.getId() == null || !this.getId().equals(other.getId()))) return false;
        return true;
     * Returns a string representation of the object.  This implementation constructs
     * that representation based on the id fields.
     * @return a string representation of the object.
    @Override
    public String toString() {
        return "ejb.NewsEntity[id=" + getId() + "]";
    public String getTitle() {
        return title;
    public void setTitle(String title) {
        this.title = title;
    public String getBody() {
        return body;
    public void setBody(String body) {
        this.body = body;
public HashMap getHm() {
        return hm;
    public void setHm(HashMap hm) {
        this.hm = hm;
PostMessage.java
public class PostMessage extends HttpServlet {
    @Resource(mappedName="jms/NewMessageFactory")
    private  ConnectionFactory connectionFactory;
    @Resource(mappedName="jms/NewMessage")
    private  Queue queue;
    /** 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 {
        response.setContentType("text/html;charset=UTF-8");
        String title=request.getParameter("title");
        String body=request.getParameter("body");
        HashMap hm = new HashMap();
        hm.put("title", request.getParameter("title"));
        hm.put("body", request.getParameter("body"));
        if ((title!=null) && (body!=null)) {
            try {
                Connection connection = connectionFactory.createConnection();
                Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
                MessageProducer messageProducer = session.createProducer(queue);
                ObjectMessage message = session.createObjectMessage();
                // here we create NewsEntity, that will be sent in JMS message
                NewsEntity e = new NewsEntity();
                e.setTitle(title);
                e.setBody(body);
                e.setHm(hm);
                message.setObject(e);               
                messageProducer.send(message);
                messageProducer.close();
                connection.close();
                // response.sendRedirect("ListNews");
            } catch (JMSException ex) {
                ex.printStackTrace();
        }(Some other code goes here to display the HTML form. not important)
ListNews.Java
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        HashMap hm = new HashMap();
        out.println("<html>");
        out.println("<head>");
        out.println("<title>Show Messages</title>");
        out.println("</head>");
        out.println("<body bgcolor='#FFCCFF'>");
        out.println("<h1>Showing all Messages</h1>");
        List news = newsEntityFacade.findAll();
        for (Iterator it = news.iterator(); it.hasNext();) {
             NewsEntity elem = (NewsEntity) it.next();
            hm = elem.getHm();
            out.println(" <table width='35%' border='0' cellpadding='1' cellspacing='1' bgcolor='#000000'> ");
            out.println("   <tr bordercolor='#000000' bgcolor='#CC99FF'> ");
            out.println("     <td width='19%' bgcolor='#CC99FF'><font color='#000000'><strong>Name</strong></font></td>");
            out.println("     <td width='81%' bgcolor='#CC99FF'><font color='#000000'>" + elem.getTitle() + "</font></td>");
            out.println("   </tr>");
            out.println("   <tr bordercolor='#000000' bgcolor='#CC99FF'> ");
            out.println("     <td><font color='#000000'><strong>Message</strong></font></td>");
            out.println("     <td><font color='#000000'>" + elem.getBody() + "</font></td>");
            out.println("   </tr>");
            out.println(" </table>");
            out.println("-----" + hm.get("title")); //I just want to try to get 1 item to see if it works
            out.println("   <br />");
        }Well thats the important parts of the code. it works fine when I send simple messages but when I try out the HashMap the servlet is displayed but no messages are sent to the queue. It would be great if anyone could help.
I know this isnt that clear but Im really tired and frustrated right now if you need more info please ask and I can supply it. Thanks

Answer 1

Hi, so I've added a weblogic-ejb.jar.xml file with a reference to the JNDI name of the work manager:
<?xml version="1.0" encoding="UTF-8"?>
<wls:weblogic-ejb-jar xmlns:wls="http://xmlns.oracle.com/weblogic/weblogic-ejb-jar" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/ejb-jar_3_0.xsd http://xmlns.oracle.com/weblogic/weblogic-ejb-jar http://xmlns.oracle.com/weblogic/weblogic-ejb-jar/1.0/weblogic-ejb-jar.xsd">
    <wls:weblogic-enterprise-bean>
        <wls:ejb-name>DependencyWorker</wls:ejb-name>
        <wls:resource-description>
            <wls:res-ref-name>MyWorkManager</wls:res-ref-name>
            <wls:jndi-name>wm/MyWorkManager</wls:jndi-name>
        </wls:resource-description>
    </wls:weblogic-enterprise-bean>
</wls:weblogic-ejb-jar>But I still get exactly the same error when I try to start my server. The example you referred to kind of cryptically suggests that adding a plan.xml suddenly fixed everything, but what am I missing here that actually hooks the work manager up to JNDI? am I getting these problems because I'm using annotations, or are people not supposed to access work managers in this way?
Thanks,
Edited by: 806682 on 05-Nov-2010 08:57