Connection Pooling

Question.
I have the following servlet:
/*
 * Created on Mar 18, 2005
 *
 * To change the template for this generated file go to
 * Window>Preferences>Java>Code Generation>Code and Comments
 */
package com.csj.bulkgarbage;

import java.io.IOException;
import java.sql.*;
import java.util.*;
import javax.naming.InitialContext;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.sql.DataSource;

import com.csj.bulkgarbage.util.*;

/**
 * @author RPower
 *
 * To change the template for this generated type comment go to
 * Window>Preferences>Java>Code Generation>Code and Comments
 */
public class CancelGarbage extends HttpServlet {
        /************************************
        * Put in the parameters and variables 
        * for datasource. 
        * 
        * @author RPower Jun 2, 2005
        ************************************/
        private static DataSource ds = null;
        private static String collectionName;
        private static String garbschedmstTable;
        private String dsname;
        private DatabaseMetaData dmd;
        private ServletContext context;
        private String jdbc_source;

        public void doGet(HttpServletRequest req, HttpServletResponse 
resp)
                throws ServletException, IOException {
                performTask(req, resp);
        }

        public void doPost(HttpServletRequest req, HttpServletResponse 
resp)
                throws ServletException, IOException {
                performTask(req, resp);
        }

        private void getDS() {
                try {
                        Hashtable parms = new Hashtable();
                        parms.put(
                                "java.naming.factory.initial",
 "com.ibm.websphere.naming.WsnInitialContextFactory");
                        InitialContext cxt = new InitialContext(parms);
                        ds = (DataSource) cxt.lookup("jdbc/" + dsname);
                } catch (Exception e) {
                        e.printStackTrace();
                }
        }

        public void init(ServletConfig config) throws ServletException {
                super.init(config);
                try {
                        context = getServletContext();
                        garbschedmstTable =
 context.getInitParameter("bulk.garbmastertable");
                        collectionName = 
context.getInitParameter("pubwrk.lib");
                        dsname = context.getInitParameter("ds.name");
                } catch (Exception e) {
                        System.err.println(e);
                }
        }

        public void performTask(HttpServletRequest req, 
HttpServletResponse resp) {
                HttpSession sess;
                Connection conn = null;
                Customer customer;
                String type;
                String date;
                String counter;
                String url;
                try {
                        sess = req.getSession(true);
                        //!---New code put in Jun 2, 2005
                        if (ds == null)
                                getDS();
                        conn = ds.getConnection();
                        dmd = conn.getMetaData();
                        // -----End New Code------->
                        BulkGarbageSchedMaster b = 
(BulkGarbageSchedMaster) sess.getAttribute("bBulkGarbage");
                        customer = (Customer) 
sess.getAttribute("customer");
                        RecordLock.unlock(ds, conn, collectionName, 
garbschedmstTable, "WGSCHDID", b.getGarbageId(), "WGINUSBY", "WGINUSTM", 
req.getRemoteUser(), false);
                        req.setAttribute("newCustomer", "no");
                        sess.setAttribute("customer", customer);
                        sess.setAttribute("disabled", "disabled");
                        if (req.getParameter("counter")!=null){
                                counter = req.getParameter("counter");
                                date = req.getParameter("date");
                                type = req.getParameter("type");
                                url = "Edit_Pickupdate_Apps?type=" + type 
+ "&date=" + date + "&counter=" + counter;
                        } else {
                                url = "LoadCustomer?" + 
customer.getCustId();
                        }
 getServletConfig().getServletContext().getRequestDispatcher(
                                url).forward(
                                req,
                                resp);
                } catch (Exception e) {
                        e.printStackTrace();
                }
        }
}

When it's being run on the server, sometimes I get the error that the 
connection is closed exception.  Basically, I think that the threads are 
modifying each other as they are running.  How do I make the connection 
thread safe?

Ron Power
Programmer
Information Services
City Of St. John's, NL
P.O. Box 908
St. John's, NL
A1C 5M2
709-576-8132
rpower@xxxxxxxxxx
http://www.stjohns.ca/
___________________________________________________________________________
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Sir Winston Churchill





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