Same old story :( "Cannot load JDBC driver class 'null'" - Mailing list pgsql-jdbc

Hi all,
first of all, sorry for this long mail, but i´m working on this problem since 4 days. And i really
need help.
I read a lot of websites about this problem but i still can't fix my problem so i hope you could
help me.

Thank you very much.

Every time i try to connect the postgresql-Database with my little JSP (running in Tomcat) i got
this Error:
--> java.sql.SQLException: Cannot load JDBC driver class 'null' <--

my environment
-----------------------------------------------
PostgreDB and Tomcat are running on the same Server.
- the DB is named "mze"
- the user for this DB is named also "mze"
- the user has no password for the DB so it's ""

my Tomcat version 4.1.18
my Tomcat is listening on Port 4444

my Tomcat-Directory is: /opt/jakarta/tomcat
the Environment varibabl is: CATALINA_HOME=/opt/jakarta/tomcat

the Name of my Webapplication is:
%CATALINA_HOME%/webapps/Timerecording

my jsp is lying in:
%CATALINA_HOME%/webapps/Timerecording/WEB-INF/jsp

my javaclass is lying in:
%CATALINA_HOME%/webapps/Timerecording/WEB-INF/src

the JDBC-Driver "pg73jdbc3.jar is lying in:
%CATALINA_HOME%/common/lib
-----------------------------------------------


web.xml of my webapp:
 -----------------------------------------------
 <?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd">

<web-app>
    <servlet>....</servlet>
    <servlet-mapping>....</servlet-mapping>

    <resource-ref>
        <description>postgreSQL Connection</description>
        <res-ref-name>jdbc/mze</res-ref-name>
        <res-type>javax.sql.DataSource</res-type>
        <res-auth>Container</res-auth>
    </resource-ref>
</web-app>
-----------------------------------------------


javaclass of my webapp
-----------------------------------------------
public class Order {
    String connectionState = "Not Connected";

    public void init() throws Exception {
        DataSource ds=null;
        Connection conn=null;

        Context ctx = new InitialContext();
        ds = (DataSource) ctx.lookup("java:comp/env/jdbc/mze");

        try{
            conn = ds.getConnection();        //<----------------EXCEPTION HERE
        }
        catch(Exception e){ throw new Exception("Boom - No Connection -->"+e);    }

        try {
            if (conn != null) {
                ...
                conn.close();
            }

        }
        catch (Exception e) {throw new Exception(" conn == null -->" + e);    }
    }
-----------------------------------------------


server.xml of my tomcat
(sorry i don´t know what is important to fix my problem.So it´s very long! Sorry!
 the most important is at the tail of this file):
-----------------------------------------------
<Server port="8005" shutdown="SHUTDOWN" debug="0">

<Listener className="org.apache.catalina.mbeans.ServerLifecycleListener" debug="0"/>
<Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener"
debug="0"/>

<GlobalNamingResources>
    <Environment name="simpleValue" type="java.lang.Integer" value="30"/>
    <Resource name="UserDatabase" auth="Container"
type="org.apache.catalina.UserDatabase"
            description="User database that can be updated and saved"></Resource>
        <ResourceParams name="UserDatabase">
        <parameter>
            <name>factory</name>
            <value>org.apache.catalina.users.MemoryUserDatabaseFactory</value>
        </parameter>
        <parameter>
            <name>pathname</name>
            <value>conf/tomcat-users.xml</value>
        </parameter>
        </ResourceParams>
</GlobalNamingResources>

<Service name="Tomcat-Standalone">

<!-- Define a non-SSL Coyote HTTP/1.1 Connector on port 8080 -->
<Connector className="org.apache.coyote.tomcat4.CoyoteConnector"
    port="4444" minProcessors="5" maxProcessors="75"
    enableLookups="true" redirectPort="8443"
    acceptCount="100" debug="0" connectionTimeout="20000"
    useURIValidationHack="false" disableUploadTimeout="true" />

<!-- Define a Coyote/JK2 AJP 1.3 Connector on port 8009 -->
<Connector className="org.apache.coyote.tomcat4.CoyoteConnector"
    port="8009" minProcessors="5" maxProcessors="75"
    enableLookups="true" redirectPort="8443"
    acceptCount="10" debug="0" connectionTimeout="0"
    useURIValidationHack="false"
    protocolHandlerClassName="org.apache.jk.server.JkCoyoteHandler"/>

<!-- Define the top level container in our container hierarchy -->
<Engine name="Standalone" defaultHost="localhost" debug="0">

<!-- Global logger unless overridden at lower levels -->
<Logger className="org.apache.catalina.logger.FileLogger"
    prefix="catalina_log." suffix=".txt"
    timestamp="true"/>

<!-- Because this Realm is here, an instance will be shared globally -->
<Realm className="org.apache.catalina.realm.UserDatabaseRealm"
    debug="0" resourceName="UserDatabase"/>

<!-- Define the default virtual host -->
<Host name="localhost" debug="0" appBase="webapps" unpackWARs="true"
autoDeploy="true">

<Logger className="org.apache.catalina.logger.FileLogger"
    directory="logs"  prefix="localhost_log." suffix=".txt" timestamp="true"/>

<!-- Tomcat Examples Context -->
<Context path="/examples" docBase="examples" debug="0" reloadable="true"
crossContext="true">
<Logger className="org.apache.catalina.logger.FileLogger"
        prefix="localhost_examples_log." suffix=".txt" timestamp="true"/>
    <Ejb   name="ejb/EmplRecord" type="Entity"
        home="com.wombat.empl.EmployeeRecordHome"
        remote="com.wombat.empl.EmployeeRecord"/>

    <Environment name="maxExemptions" type="java.lang.Integer" value="15"/>
    <Parameter name="context.param.name" value="context.param.value"
override="false"/>

    <Resource name="jdbc/EmployeeAppDb" auth="SERVLET"
type="javax.sql.DataSource"/>
        <ResourceParams name="jdbc/EmployeeAppDb">
            <parameter><name>username</name><value>sa</value></parameter>
            <parameter><name>password</name><value></value></parameter>

<parameter><name>driverClassName</name><value>org.hsql.jdbcDriver</value></parameter>

<parameter><name>url</name><value>jdbc:HypersonicSQL:database</value></parameter>
        </ResourceParams>

    <Resource name="mail/Session" auth="Container" type="javax.mail.Session"/>
        <ResourceParams name="mail/Session">

<parameter><name>mail.smtp.host</name><value>localhost</value></parameter>
        </ResourceParams>

    <ResourceLink name="linkToGlobalResource"
        global="simpleValue"
        type="java.lang.Integer"/>

</Context>

<Context path="/webapps/Timerecording" docBase="Timerecording" debug="0"
                reloadable="true" crossContext="true">

    <!--  PostgreSQL anbindung -->
    <Resource name="jdbc/mze" auth="Container" type="javax.sql.DataSource"/>
    <ResourceParams name="jdbc/mze">
        <parameter>
            <name>factory</name>
            <value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
        </parameter>
        <parameter>
            <name>url</name>
            <value>jdbc:postgresql://127.0.0.1:5432/mze</value>
        </parameter>
        <parameter>
            <name>driverClassName</name>
            <value>org.postgresql.Driver</value>
        </parameter>
            <parameter>
            <name>username</name>
            <value>mze</value>
        </parameter>
        <parameter>
            <name>password</name>
            <value>mze</value>
        </parameter>
        <parameter>
            <name>maxActive</name>
            <value>20</value>
        </parameter>
        <parameter>
            <name>maxIdle</name>
            <value>10</value>
        </parameter>
        <parameter>
            <name>maxWait</name>
            <value>3000</value>
        </parameter>
    </ResourceParams>
</Context>

</Host>
</Engine>
</Service>
</Server>
-----------------------------------------------

Thank you for all help
Matthias









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