Following are the main Source files of this application

/*
 * @author Rajat Gupta
 * @version 1.0
 *

 * Name of the Application        : SendMessage.java
 * Development Environment       : Oracle9i JDeveloper
 * Creation/Modification History  :
 *
 *
 *   Rajat Gupta        28-May-2003        Created
*/

package oracle.otnsamples.oc4jjms;


// IO Imports
import java.io.IOException;

// JMS Imports
import javax.jms.Queue;
import javax.jms.QueueConnection;
import javax.jms.QueueConnectionFactory;
import javax.jms.QueueSender;
import javax.jms.QueueSession;
import javax.jms.Session;


// Naming Imports
import javax.naming.Context;
import javax.naming.InitialContext;

// Servlet Imports
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;

// HTTP Servlet Imports
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


/**
 * This Servlet creates a connection to the queue and enqueues the message
 * sent by the Chat client to the queue. It uses JMS APIs to do this.
 */

public class SendMessage extends HttpServlet {

  /**
   * QueueConnectionFactory Object
   */
  //QueueConnectionFactory queueCF;


  /**
   * QueueConnection Object
   */
  QueueConnection queueConnection;

  /**
   * QueueSession Object
   */
  QueueSession queueSession;

  /**
   * Queue object
   */
  Queue queue;


  /**
   * Object of the sender. The application enqueues messages to the queue
   * through this object.
   */
  QueueSender sender;

  /**
   * Init method of the Servlet. This method initializes various objects.
   *
   * @exception ServletException
   *
   * @param config ServletConfig Object
   */
  public void init(ServletConfig config) throws ServletException{

    super.init(config);
    try{

      // Get the Initial Context
      Context jndiContext = new InitialContext();

      // Lookup the QueueConnection factory and create the
      // QueueConnectionFactory object
      QueueConnectionFactory queueCF = (QueueConnectionFactory)jndiContext.lookup
            ("jms/MainQueueConnectionFactory");

      // Create a Connection to the QueueTable. The connection is created in
      // stopped mode. No messages will be delivered until the
      // Connection.start method is explicitly called.
      queueConnection = queueCF.createQueueConnection();


      // Create a Session to the queue. It takes in two parameters which are
      //  1) Transacted - Indicates whether the session is transacted. This
      //     is a boolean value.
      //  2) AcknowledgeMode - Indicates whether the consumer or the client
      //     will acknowledge any messages it receives; ignored if the
      //     session is transacted. Valid values are Session.AUTO_ACKNOWLEDGE,
      //     Session.CLIENT_ACKNOWLEDGE and Session.DUPS_OK_ACKNOWLEDGE.
      queueSession = queueConnection.createQueueSession
                                           (true, Session.AUTO_ACKNOWLEDGE);

      // Lookup the Queue and create its object.
      queue = (Queue)jndiContext.lookup
                              ("jms/MainQueue");

      // Creates an object to send messages to the specified queue
      sender = queueSession.createSender(queue);


      // Close the context
      jndiContext.close();

      // Start the Connection
      queueConnection.start();
    }catch(Exception e){
      // Print the exception on the console
      e.printStackTrace();
    }
  }

  /**
   * This method is invoked when a client sends a message to this servlet.
   *
   * @exception ServletException
   * @exception IOException
   *
   * @param request ServletRequest Object

   * @param response ServletResponse Object
   */
  public void doGet(HttpServletRequest request, HttpServletResponse response)
                                          throws ServletException, IOException{
    try{
      // Get the message to be enqueued
      String message = request.getParameter("msg");

      // Enqueue the message in the queue. This method uses the default
      // delivery mode, priority, and time to live.
      sender.send(queueSession.createTextMessage(message));

      // Commit the transaction
      queueSession.commit();

    }catch(Exception e){
      // Print the exception on the console
      e.printStackTrace();
    }

  }

  /**
   * This method redirects the client request to the doGet() method.
   *
   * @exception ServletException
   * @exception IOException
   *
   * @param request
   * @param response
   */
  public void doPost(HttpServletRequest request, HttpServletResponse response)
                                          throws ServletException, IOException{
    doGet(request, response);
  }

  /**
   * This method will be called when the Servlet is destroyed. It closes
   * various objects that are no longer required by the application.
   */

  public void destroy(){
    try{
      // Close the connection
      queueConnection.stop();

      // Close the various resources
      sender.close();
      queueSession.close();
      queueConnection.close();
    }catch(Exception e){
      // Print the exception on the console
      e.printStackTrace();
    }
  }
}