Thread: Tomcat - PostgreSQL - Cannot load JDBC driver class "null"

Craig,

So what happens, does it fail, does it run, does it throw an exeption?

Dave
On Fri, 2003-09-26 at 12:29, CRAIG GOLBY wrote:
> Help, I am tearing my hair out.
>
> I am a newbie to Linux and Tomcat, and am therefore amazed that I have
> got as far as I have, that said I now seem to be stuck in front of a
> brick wall, with no ladder !!
>
> Tomcat 4.1.24 is running on ServerOne (Red Hat 9), it is currently
> serving out a couple of very basic JSP's and seems to be working quite
> well. ServerOne also has J2SDK 1.4.1_03 installed.  PostgreSQL 7.3 is
> running on ServerTwo (Red Hat 9).  Have also installed pgAdminIII on
> both a Windows Laptop and ServerTwo.  The Laptop version works fine,
> if a little unstable, so TCP/IP connectivity is working fine.
>
> Within PostgreSQL I have created a new Db called "PersonalDb", within
> the public Schema I have created a table called "testOne".  TestOne
> has three columns, Id, FieldOne and DateStamp, and there are currently
> 2 rows of data within the table
>
> Sample of code used is below, along with a list of the Jar files in
> common/lib.
>
> I have read through so many mailing lists now and tried so many things
> that I dont know what I have and havent done, am fairly sure that it
> is either a configuration issue or a missing file so will no doubt
> kick myself when I find out the answer.
>
> Any assistance would be greatly appreciated.
>
> Regards
>
>
> Craig
>
>
> *******************************************************
> Server XML :- Tomcat/conf
> *******************************************************
> <Context path="/DBTest"
>          docBase="DBTest"
>          debug="5"
>          reloadable="true"
>          crossContext="true">
>
> <Logger className="org.apache.catalina.logger.FileLogger"
>         prefix="localhost_DBTest_log." suffix=".txt"
>         timestamp="true"/>
>
> <Resource name="jdbc/PersonalDb"
>           type="javax.sql.DataSource"
>           auth="Container"/>
>
> <ResourceParams name="jdbc/PersonalDb">
>  <parameter>
>   <name>factory</name>
>   <value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
>  </parameter>
>
>  <parameter>
>   <name>driverClassName</name>
>   <value>org.postgresql.Driver</value>
>  </parameter>
>
>  <parameter>
>   <name>url</name>
>   <value>jdbc:postgresql://ServerTwo:5432/PersonalDb</value>
>  </parameter>
>
>  <parameter>
>   <name>username</name>
>   <value>myUser</value>
>  </parameter>
>
>  <parameter>
>   <name>password</name>
>   <value>myPassword</value>
>  </parameter>
>
>  <parameter>
>   <name>maxActive</name>
>   <value>10</value>
>  </parameter>
>
>  <parameter>
>   <name>maxIdle</name>
>   <value>30</value>
>  </parameter>
>
>  <parameter>
>   <name>maxWait</name>
>   <value>10000</value>
>  </parameter>
>
> </ResourceParams>
> </Context>
>
> </Host>
> </Engine>
> </Service>
>
>
> *******************************************************
> Web XML  :-  Tomcat/webapps/root/WEB-INF
> *******************************************************
>   <description>PostgreSQL Test App</description>
>     <resource-ref>
>        <description>postgreSQL Datasource example</description>
>        <res-ref-name>jdbc/PersonalDb</res-ref-name>
>        <res-type>javax.sql.DataSource</res-type>
>        <res-auth>Container</res-auth>
>    </resource-ref>
>
>
>
> *******************************************************
> My Class File
> *******************************************************
>
>   public void init() {
>     try{
>       Context ctx = new InitialContext();
>       if(ctx == null )
>           throw new Exception("Boom - No Context");
>       status = "checking CTX";
>
>       DataSource ds =
> (DataSource)ctx.lookup("java:comp/env/jdbc/PersonalDb");
>       status = "Completing Lookup of CTX";
>
>       if (ds != null)
>         {
>          status = "Creating Connection";
>          Connection conn = ds.getConnection();   <----- FAILS HERE
>          status = "Created Connection";
>          if(conn != null)
>            {
>             foo = "Got Connection "+conn.toString();
>             Statement stmt = conn.createStatement();
>             ResultSet rst =
>                 stmt.executeQuery(
>                   "select Id, FieldOne, DateStamp from
> Public.testOne");
>             status = "Completing Select";
>             if(rst.next())
>             {
>                foo=rst.getString(2);
>                bar=rst.getInt(3);
>             }
>             status = "Looped through Resultset";
>             conn.close();
>            }
>         }
>       else {status = "Fell into Else";}
>     }catch(Exception e) {
>       e.printStackTrace();
>         status = status + ", now in exception block :-" +
> e.toString();
>
>     }
>  }
>
> *******************************************************
> Class Files in Tomcat/common/lib
> *******************************************************
> activation.jar
> ant.jar
> collections-2.1.jar
> commons-collections.jar
> commons-dbcp-1.0.jar
> commons-dbcp.jar
> commons-logging-api.jar
> commons-pool.jar
> jasper-compiler.jar
> jasper-runtime.jar
> jdbc2_0-stdext.jar
> jndi.jar
> jta.jar
> mail.jar
> naming-common.jar
> naming-factory.jar
> naming-resources.jar
> pg73jdbc3.jar
> pool-1.0.1.jar
> postgresql.jar    (Copy of  pg73jdbc3.jar)
> servlet.jar
>
>
>
>
>
--
Dave Cramer <Dave@micro-automation.net>

You've probably checked this, but on the offchance you haven't, are you
explicitly pointing to the postgres jdbc jar file in your classpath?
eg
CLASSPATH=$CLASSPATH:.:...whatever...:/usr/local/Tomcat/common/lib/pg73jdbc3.jar

Ron

CRAIG GOLBY wrote:

> Help, I am tearing my hair out.
>
> I am a newbie to Linux and Tomcat, and am therefore amazed that I have
> got as far as I have, that said I now seem to be stuck in front of a
> brick wall, with no ladder !!
>
> Tomcat 4.1.24 is running on ServerOne (Red Hat 9), it is currently
> serving out a couple of very basic JSP's and seems to be working quite
> well. ServerOne also has J2SDK 1.4.1_03 installed.  PostgreSQL 7.3 is
> running on ServerTwo (Red Hat 9).  Have also installed pgAdminIII on
> both a Windows Laptop and ServerTwo.  The Laptop version works fine,
> if a little unstable, so TCP/IP connectivity is working fine.
>
> Within PostgreSQL I have created a new Db called "PersonalDb", within
> the public Schema I have created a table called "testOne".  TestOne
> has three columns, Id, FieldOne and DateStamp, and there are currently
> 2 rows of data within the table
>
> Sample of code used is below, along with a list of the Jar files in
> common/lib.
>
> I have read through so many mailing lists now and tried so many things
> that I dont know what I have and havent done, am fairly sure that it
> is either a configuration issue or a missing file so will no doubt
> kick myself when I find out the answer.
>
> Any assistance would be greatly appreciated.
>
> Regards
>
>
> Craig
>
>
> *******************************************************
> Server XML :- Tomcat/conf
> *******************************************************
> <Context path="/DBTest"
>          docBase="DBTest"
>          debug="5"
>          reloadable="true"
>          crossContext="true">
>
> <Logger className="org.apache.catalina.logger.FileLogger"
>         prefix="localhost_DBTest_log." suffix=".txt"
>         timestamp="true"/>
>
> <Resource name="jdbc/PersonalDb"
>           type="javax.sql.DataSource"
>           auth="Container"/>
>
> <ResourceParams name="jdbc/PersonalDb">
>  <parameter>
>   <name>factory</name>
>   <value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
>  </parameter>
>
>  <parameter>
>   <name>driverClassName</name>
>   <value>org.postgresql.Driver</value>
>  </parameter>
>
>  <parameter>
>   <name>url</name>
>   <value>jdbc:postgresql://ServerTwo:5432/PersonalDb</value>
>  </parameter>
>
>  <parameter>
>   <name>username</name>
>   <value>myUser</value>
>  </parameter>
>
>  <parameter>
>   <name>password</name>
>   <value>myPassword</value>
>  </parameter>
>
>  <parameter>
>   <name>maxActive</name>
>   <value>10</value>
>  </parameter>
>
>  <parameter>
>   <name>maxIdle</name>
>   <value>30</value>
>  </parameter>
>
>  <parameter>
>   <name>maxWait</name>
>   <value>10000</value>
>  </parameter>
>
> </ResourceParams>
> </Context>
>
> </Host>
> </Engine>
> </Service>
>
>
> *******************************************************
> Web XML  :-  Tomcat/webapps/root/WEB-INF
> *******************************************************
>   <description>PostgreSQL Test App</description>
>     <resource-ref>
>        <description>postgreSQL Datasource example</description>
>        <res-ref-name>jdbc/PersonalDb</res-ref-name>
>        <res-type>javax.sql.DataSource</res-type>
>        <res-auth>Container</res-auth>
>    </resource-ref>
>
>
> *******************************************************
> My Class File
> *******************************************************
>
>   public void init() {
>     try{
>       Context ctx = new InitialContext();
>       if(ctx == null )
>           throw new Exception("Boom - No Context");
>       status = "checking CTX";
>
>       DataSource ds =
> (DataSource)ctx.lookup("java:comp/env/jdbc/PersonalDb");
>       status = "Completing Lookup of CTX";
>
>       if (ds != null)
>         {
>          status = "Creating Connection";
>          Connection conn = ds.getConnection();   <----- FAILS HERE
>          status = "Created Connection";
>          if(conn != null)
>            {
>             foo = "Got Connection "+conn.toString();
>             Statement stmt = conn.createStatement();
>             ResultSet rst =
>                 stmt.executeQuery(
>                   "select Id, FieldOne, DateStamp from Public.testOne");
>             status = "Completing Select";
>             if(rst.next())
>             {
>                foo=rst.getString(2);
>                bar=rst.getInt(3);
>             }
>             status = "Looped through Resultset";
>             conn.close();
>            }
>         }
>       else {status = "Fell into Else";}
>     }catch(Exception e) {
>       e.printStackTrace();
>         status = status + ", now in exception block :-" + e.toString();
>
>     }
>  }
> *******************************************************
> Class Files in Tomcat/common/lib
> *******************************************************
> activation.jar
> ant.jar
> collections-2.1.jar
> commons-collections.jar
> commons-dbcp-1.0.jar
> commons-dbcp.jar
> commons-logging-api.jar
> commons-pool.jar
> jasper-compiler.jar
> jasper-runtime.jar
> jdbc2_0-stdext.jar
> jndi.jar
> jta.jar
> mail.jar
> naming-common.jar
> naming-factory.jar
> naming-resources.jar
> pg73jdbc3.jar
> pool-1.0.1.jar
> postgresql.jar    (Copy of  pg73jdbc3.jar)
> servlet.jar
>
>
>
>
>

I hadnt, but I have now.

The command used was

CLASSPATH=/usr/local/tomcat/bin/bootstrap.jar:/usr/src/Java/j2sdk1.4.1_0
3/lib/tools.jar:/usr/local/tomcat/common/lib/servlet.jar:/usr/local/tomc
at/common/lib/pg73jdbc3.jar

Which resulted in

.
.
CATALINA_HOME=/usr/local/tomcat
CLASSPATH=/usr/local/tomcat/bin/bootstrap.jar:/usr/src/Java/j2sdk1.4.1_0
3/lib/tools.jar:/usr/local/tomcat/common/lib/servlet.jar:/usr/local/tomc
at/common/lib/pg73jdbc3.jar
COLORS=/etc/DIR_COLORS.xterm
.
.

Unfortunately it made no difference to the problem

Thanks anyway


-----Original Message-----
From: Ron [mailto:rstpierre@syscor.com]
Sent: 26 September 2003 18:36
Cc: CRAIG GOLBY; pgsql-jdbc

You've probably checked this, but on the offchance you haven't, are you
explicitly pointing to the postgres jdbc jar file in your classpath?
eg
CLASSPATH=$CLASSPATH:.:...whatever...:/usr/local/Tomcat/common/lib/pg73j
dbc3.jar

Ron

CRAIG GOLBY wrote:

> Help, I am tearing my hair out.
>
> I am a newbie to Linux and Tomcat, and am therefore amazed that I have

> got as far as I have, that said I now seem to be stuck in front of a
> brick wall, with no ladder !!
>
> Tomcat 4.1.24 is running on ServerOne (Red Hat 9), it is currently
> serving out a couple of very basic JSP's and seems to be working quite

> well. ServerOne also has J2SDK 1.4.1_03 installed.  PostgreSQL 7.3 is
> running on ServerTwo (Red Hat 9).  Have also installed pgAdminIII on
> both a Windows Laptop and ServerTwo.  The Laptop version works fine,
> if a little unstable, so TCP/IP connectivity is working fine.
>
> Within PostgreSQL I have created a new Db called "PersonalDb", within
> the public Schema I have created a table called "testOne".  TestOne
> has three columns, Id, FieldOne and DateStamp, and there are currently
> 2 rows of data within the table
>
> Sample of code used is below, along with a list of the Jar files in
> common/lib.
>
> I have read through so many mailing lists now and tried so many things

> that I dont know what I have and havent done, am fairly sure that it
> is either a configuration issue or a missing file so will no doubt
> kick myself when I find out the answer.
>
> Any assistance would be greatly appreciated.
>
> Regards
>
>
> Craig
>
>
> *******************************************************
> Server XML :- Tomcat/conf
> *******************************************************
> <Context path="/DBTest"
>          docBase="DBTest"
>          debug="5"
>          reloadable="true"
>          crossContext="true">
>
> <Logger className="org.apache.catalina.logger.FileLogger"
>         prefix="localhost_DBTest_log." suffix=".txt"
>         timestamp="true"/>
>
> <Resource name="jdbc/PersonalDb"
>           type="javax.sql.DataSource"
>           auth="Container"/>
>
> <ResourceParams name="jdbc/PersonalDb">  <parameter>
>   <name>factory</name>
>   <value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
>  </parameter>
>
>  <parameter>
>   <name>driverClassName</name>
>   <value>org.postgresql.Driver</value>
>  </parameter>
>
>  <parameter>
>   <name>url</name>
>   <value>jdbc:postgresql://ServerTwo:5432/PersonalDb</value>
>  </parameter>
>
>  <parameter>
>   <name>username</name>
>   <value>myUser</value>
>  </parameter>
>
>  <parameter>
>   <name>password</name>
>   <value>myPassword</value>
>  </parameter>
>
>  <parameter>
>   <name>maxActive</name>
>   <value>10</value>
>  </parameter>
>
>  <parameter>
>   <name>maxIdle</name>
>   <value>30</value>
>  </parameter>
>
>  <parameter>
>   <name>maxWait</name>
>   <value>10000</value>
>  </parameter>
>
> </ResourceParams>
> </Context>
>
> </Host>
> </Engine>
> </Service>
>
>
> *******************************************************
> Web XML  :-  Tomcat/webapps/root/WEB-INF
> *******************************************************
>   <description>PostgreSQL Test App</description>
>     <resource-ref>
>        <description>postgreSQL Datasource example</description>
>        <res-ref-name>jdbc/PersonalDb</res-ref-name>
>        <res-type>javax.sql.DataSource</res-type>
>        <res-auth>Container</res-auth>
>    </resource-ref>
>
>
> *******************************************************
> My Class File
> *******************************************************
>
>   public void init() {
>     try{
>       Context ctx = new InitialContext();
>       if(ctx == null )
>           throw new Exception("Boom - No Context");
>       status = "checking CTX";
>
>       DataSource ds =
> (DataSource)ctx.lookup("java:comp/env/jdbc/PersonalDb");
>       status = "Completing Lookup of CTX";
>
>       if (ds != null)
>         {
>          status = "Creating Connection";
>          Connection conn = ds.getConnection();   <----- FAILS HERE
>          status = "Created Connection";
>          if(conn != null)
>            {
>             foo = "Got Connection "+conn.toString();
>             Statement stmt = conn.createStatement();
>             ResultSet rst =
>                 stmt.executeQuery(
>                   "select Id, FieldOne, DateStamp from
Public.testOne");
>             status = "Completing Select";
>             if(rst.next())
>             {
>                foo=rst.getString(2);
>                bar=rst.getInt(3);
>             }
>             status = "Looped through Resultset";
>             conn.close();
>            }
>         }
>       else {status = "Fell into Else";}
>     }catch(Exception e) {
>       e.printStackTrace();
>         status = status + ", now in exception block :-" +
> e.toString();
>
>     }
>  }
> *******************************************************
> Class Files in Tomcat/common/lib
> *******************************************************
> activation.jar
> ant.jar
> collections-2.1.jar
> commons-collections.jar
> commons-dbcp-1.0.jar
> commons-dbcp.jar
> commons-logging-api.jar
> commons-pool.jar
> jasper-compiler.jar
> jasper-runtime.jar
> jdbc2_0-stdext.jar
> jndi.jar
> jta.jar
> mail.jar
> naming-common.jar
> naming-factory.jar
> naming-resources.jar
> pg73jdbc3.jar
> pool-1.0.1.jar
> postgresql.jar    (Copy of  pg73jdbc3.jar)
> servlet.jar
>
>
>
>
>

On 26/09/2003 17:29 CRAIG GOLBY wrote:
> [snip]
>   public void init() {
>     try{
>       Context ctx = new InitialContext();
>       if(ctx == null )
>           throw new Exception("Boom - No Context");
>       status = "checking CTX";
>
>       DataSource ds =
> (DataSource)ctx.lookup("java:comp/env/jdbc/PersonalDb");
>       status = "Completing Lookup of CTX";
>
>       if (ds != null)
>         {
>          status = "Creating Connection";
>          Connection conn = ds.getConnection();   <----- FAILS HERE

With a NullPointerException I presume? Try

       DataSource ds =
(DataSource)ctx.lookupLink("java:comp/env/jdbc/PersonalDb");

And rememeber that the JDBC driver _must_ be in common/lib and _must not_
be in the classpath.

HTH

--
Paul Thomas
+------------------------------+---------------------------------------------+
| Thomas Micro Systems Limited | Software Solutions for the Smaller
Business |
| Computer Consultants         |
http://www.thomas-micro-systems-ltd.co.uk   |
+------------------------------+---------------------------------------------+

On 27/09/2003 10:23 Paul Thomas wrote:
>
> With a NullPointerException I presume? Try
>
>       DataSource ds =
> (DataSource)ctx.lookupLink("java:comp/env/jdbc/PersonalDb");
>
> And rememeber that the JDBC driver _must_ be in common/lib and _must
> not_ be in the classpath.

Whoops! Actually looking at source code instead relying on memory, that
should be something like

        InitialContext cxt = new InitialContext();
        Context ctx2 = (Context)ctx.lookup("java:comp/env");
        DataSource ds = (DataSource)ctx2.lookupLink("jdbc/PersonalDb");

Which is the only way I could find which worked on Tomcat 4.1.12. I've
just retried this on 4.1.24

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

and that works too so whatever the problem was on the older version seems
to have been fixed.

--
Paul Thomas
+------------------------------+---------------------------------------------+
| Thomas Micro Systems Limited | Software Solutions for the Smaller
Business |
| Computer Consultants         |
http://www.thomas-micro-systems-ltd.co.uk   |
+------------------------------+---------------------------------------------+