i am having problem in establishing connection pooling

i am using tomcat 6, postgresql 8.1.11

/META-INF/context.xml
Java Code:
<?xml version=”1.0? encoding=”UTF-8??><Context path="/envosys" docBase="envosys" debug="5" reloadable="true" crossContext="true"><Resource name="jdbc/test"auth="Container" type="javax.sql.DataSource" factory="org.apache.tomcat.dbcp.dbcp.BasicDataSourceFactory" username="root" password="" driverClassName="org.postgresql.Driver" url="jdbc:postgresql://localhost:5432/envosys?autoReconnect=true" maxWait="1000" removeAbandoned="true" maxActive="30" maxIdle="10" removeAbandonedTimeout="60" logAbandoned="true" /> </Context>
server.xml

Java Code:
<?xml version='1.0' encoding='utf-8'?><!--  Licensed to the Apache Software Foundation (ASF) under one or more  contributor license agreements.  See the NOTICE file distributed with  this work for additional information regarding copyright ownership.  The ASF licenses this file to You under the Apache License, Version 2.0  (the "License"); you may not use this file except in compliance with  the License.  You may obtain a copy of the License at
      http://www.apache.org/licenses/LICENSE-2.0
  Unless required by applicable law or agreed to in writing, software  distributed under the License is distributed on an "AS IS" BASIS,  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the License for the specific language governing permissions and  limitations under the License.--><!-- Note:  A "Server" is not itself a "Container", so you may not     define subcomponents such as "Valves" at this level.     Documentation at /docs/config/server.html --><Server port="8005" shutdown="SHUTDOWN">
  <!--APR library loader. Documentation at /docs/apr.html -->  <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" />  <!--Initialize Jasper prior to webapps are loaded. Documentation at /docs/jasper-howto.html -->  <Listener className="org.apache.catalina.core.JasperListener" />  <!-- Prevent memory leaks due to use of particular java/javax APIs-->  <Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener" />  <!-- JMX Support for the Tomcat server. Documentation at /docs/non-existent.html -->  <Listener className="org.apache.catalina.mbeans.ServerLifecycleListener" />  <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />
  <!-- Global JNDI resources       Documentation at /docs/jndi-resources-howto.html  -->  <GlobalNamingResources>    <!-- Editable user database that can also be used by         UserDatabaseRealm to authenticate users    -->    <Resource name="UserDatabase" auth="Container"              type="org.apache.catalina.UserDatabase"              description="User database that can be updated and saved"              factory="org.apache.catalina.users.MemoryUserDatabaseFactory"              pathname="conf/tomcat-users.xml" />  </GlobalNamingResources>
  <!-- A "Service" is a collection of one or more "Connectors" that share       a single "Container" Note:  A "Service" is not itself a "Container",        so you may not define subcomponents such as "Valves" at this level.       Documentation at /docs/config/service.html   -->  <Service name="Catalina">      <!--The connectors can use a shared executor, you can define one or more named thread pools-->    <!--    <Executor name="tomcatThreadPool" namePrefix="catalina-exec-"         maxThreads="150" minSpareThreads="4"/>    -->            <!-- A "Connector" represents an endpoint by which requests are received         and responses are returned. Documentation at :         Java HTTP Connector: /docs/config/http.html (blocking & non-blocking)         Java AJP  Connector: /docs/config/ajp.html         APR (HTTP/AJP) Connector: /docs/apr.html         Define a non-SSL HTTP/1.1 Connector on port 8080    -->    <Connector port="80" protocol="HTTP/1.1"                connectionTimeout="20000"                redirectPort="8443" />    <!-- A "Connector" using the shared thread pool-->    <!--    <Connector executor="tomcatThreadPool"               port="80" protocol="HTTP/1.1"                connectionTimeout="20000"                redirectPort="8443" />    -->               <!-- Define a SSL HTTP/1.1 Connector on port 8443         This connector uses the JSSE configuration, when using APR, the          connector should be using the OpenSSL style configuration         described in the APR documentation -->    <!--    <Connector port="8443" protocol="HTTP/1.1" SSLEnabled="true"               maxThreads="150" scheme="https" secure="true"               clientAuth="false" sslProtocol="TLS" />    -->
    <!-- Define an AJP 1.3 Connector on port 8009 -->    <Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />

    <!-- An Engine represents the entry point (within Catalina) that processes         every request.  The Engine implementation for Tomcat stand alone         analyzes the HTTP headers included with the request, and passes them         on to the appropriate Host (virtual host).         Documentation at /docs/config/engine.html -->
    <!-- You should set jvmRoute to support load-balancing via AJP ie :    <Engine name="Catalina" defaultHost="localhost" jvmRoute="jvm1">             -->     <Engine name="Catalina" defaultHost="localhost">
      <!--For clustering, please take a look at documentation at:          /docs/cluster-howto.html  (simple how to)          /docs/config/cluster.html (reference documentation) -->      <!--      <Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"/>      -->        
      <!-- The request dumper valve dumps useful debugging information about           the request and response data received and sent by Tomcat.           Documentation at: /docs/config/valve.html -->      <!--      <Valve className="org.apache.catalina.valves.RequestDumperValve"/>      -->
      <!-- This Realm uses the UserDatabase configured in the global JNDI           resources under the key "UserDatabase".  Any edits           that are performed against this UserDatabase are immediately           available for use by the Realm.  -->      <Realm className="org.apache.catalina.realm.UserDatabaseRealm"             resourceName="UserDatabase"/>
      <!-- Define the default virtual host           Note: XML Schema validation will not work with Xerces 2.2.       -->      <Host name="localhost"  appBase="webapps"            unpackWARs="true" autoDeploy="true"            xmlValidation="false" xmlNamespaceAware="false">
        <!-- SingleSignOn valve, share authentication between web applications             Documentation at: /docs/config/valve.html -->        <!--        <Valve className="org.apache.catalina.authenticator.SingleSignOn" />        -->
        <!-- Access log processes all example.             Documentation at: /docs/config/valve.html -->        <!--        <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"                 prefix="localhost_access_log." suffix=".txt" pattern="common" resolveHosts="false"/>        -->
      </Host>    </Engine>  </Service></Server>
web.xml
Java Code:
<?xml version="1.0" encoding="ISO-8859-1"?><!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN" "http://java.sun.com/j2ee/dtds/web-app_2_2.dtd"><web-app> <session-config></session-config> <session-timeout>30</session-timeout> <!-- The Welcome File List --> <welcome-file-list></welcome-file-list> <welcome-file>../form/CartingEntry.jsp</welcome-file>
<servlet>        <servlet-name>CartingEntry</servlet-name>        <servlet-class>CartingEntry</servlet-class>        </servlet> <servlet>        <servlet-name>CartingEntryT</servlet-name>        <servlet-class>CartingEntryT</servlet-class>        </servlet> <servlet>        <servlet-name>VesselVoyage</servlet-name>        <servlet-class>VesselVoyage</servlet-class>        </servlet> <servlet>        <servlet-name>LineBooking_VesselDetails</servlet-name>        <servlet-class>LineBooking_VesselDetails</servlet-class>        </servlet>
        <servlet-mapping>        <servlet-name>CartingEntry</servlet-name>        <url-pattern>/servlet/CartingEntry</url-pattern>        </servlet-mapping> <servlet-mapping>        <servlet-name>CartingEntryT</servlet-name>        <url-pattern>/servlet/CartingEntryT</url-pattern>        </servlet-mapping> <servlet-mapping>        <servlet-name>VesselVoyage</servlet-name>        <url-pattern>/servlet/VesselVoyage</url-pattern>        </servlet-mapping> <servlet-mapping>        <servlet-name>LineBooking_VesselDetails</servlet-name>        <url-pattern>/servlet/LineBooking_VesselDetails</url-pattern>        </servlet-mapping>
      <resource-ref>      <res-ref-name>jdbc/test</res-ref-name>      <res-type>javax.sql.DataSource</res-type>      <res-auth>Container</res-auth>      </resource-ref>
</web-app>
i am using following code to connect

Java Code:
package cartingentry;
import java.io.IOException;
import javax.naming.InitialContext;
import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.*;
import javax.sql.*;
public class CartingEntry extends HttpServlet
{ 
private DataSource dataSource=null;
private Connection connection=null;
private Statement statement; 
ServletConfig sc;
public void init(ServletConfig sc)
        {
           this.sc=sc;  
      } /* public void init() throws ServletException  { try {               // Get DataSource               Context initContext  = new InitialContext();               Context envContext  = (Context)initContext.lookup("java:/comp/env");   System.out.println("iniiiiiiittttttiii");
             dataSource = (DataSource)envContext.lookup("jdbc/test");                  }  catch (NamingException e) {               e.printStackTrace();           }  
     }   */
        public void doGet(HttpServletRequest req,HttpServletResponse resp) throws ServletException,IOException        {
String billno=(String)req.getParameter("billno"); System.out.println("===billno=="+billno); ResultSet resultSet = null;
 try { 
Context initContext  = new InitialContext();  
                      Context envContext  = (Context)initContext.lookup("java:/comp/env");
                        System.out.println("iniiiiiiittttttiii=="+envContext);
                        dataSource = (DataSource)envContext.lookup("jdbc/test");                                    if(dataSource!=null)            {             connection = dataSource.getConnection();             statement = connection.createStatement();              resultSet=statement.executeQuery("select * from carting");             while(resultSet.next())             {             System.out.println("billno==="+resultSet.getString(1));             }            }          //System.out.println("insert into carting values('"billno"')");          // int i=statement.executeUpdate("insert into carting values('"billno"')");            else            {             String message = "Could not find our DataSource in DBBroker. We're about to have problems.";                System.err.println("*** " + message);                throw new Exception(message);                          }            req.setAttribute("message","SUCCESS===BILLNO=="+billno);    sc.getServletContext().getRequestDispatcher("/form/CartingEntry.jsp").forward(req,resp);                System.out.println("afte dispatcher");                }                catch(Exception e)                {                        try                        {                        }                        catch(Exception ex)                        {                                System.out.println(ex);                        }                        System.out.println(e);                        sc.getServletContext().getRequestDispatcher("/form/CartingEntry.jsp").forward(req,resp);                }
        }
i have copied postgresql-8.1-414.jdbc2.jar in tomcat/lib

on trying the following error log comes

Java Code:
org.apache.tomcat.dbcp.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1150)
        at org.apache.tomcat.dbcp.dbcp.BasicDataSource.getConnection(BasicDataSource.java:880)
        at CartingEntry.doGet(CartingEntry.java:44)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
        at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852)
        at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
        at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
        at java.lang.Thread.run(Thread.java:595)

Caused by: java.lang.NullPointerException
        at org.postgresql.Driver.parseURL(Driver.java:530)
        at org.postgresql.Driver.acceptsURL(Driver.java:388)

        at java.sql.DriverManager.getDriver(DriverManager.java:232)
        at org.apache.tomcat.dbcp.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1143)
        ... 16 more
please help me out