Java Database Connectivity (JDBC)

Hi

I've been struggling for a few days with this now, so I think it's time to ask for help.

I have the following software installed:

Centos 4.6 i386 (Kernel 2.6.25)
JDK 6 Update 7
J2EE SDK 5.05
MySQL 5.0.51a

I have mostly default configuration and have copied the drivers (both mm.mysql-2.0.14-bin.jar & mysql-connector-java-3.0.17-ga-bin.jar) to /opt/SDK/lib.

Database name is userdb, is hosted on local machine, MySQL accepts both Unix & TCP/IP connections. Non-JDBC JSP pages work 100%.

I have the following file in /opt/SDK/domains/domain1/docroot/userlist.jsp (surrounding HTML removed):

Class.forName("org.gjt.mm.mysql.Driver").newInstance(); // have tried the other driver as well

String url="jdbc:mysql://localhost/userdb?user=useradm&password=removed";

out.println(url);

try {
Connection con = DriverManager.getConnection(url);
ResultSet rst = null;
Statement stmt = con.createStatement();
stmt.executeQuery("SELECT username FROM users");

while (rst.next()){
%>
<%= rst.getString("username") %>
<%
}
rst.close();
stmt.close();
con.close();
} finally { // removed the catch block for testing purposes
}

Get the following output when accessing http://localhost:8080/userlist.jsp:

HTTP Status 500 -
type Exception report
message
descriptionThe server encountered an internal error () that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: java.lang.NullPointerException
root cause
java.lang.NullPointerException
note The full stack traces of the exception and its root causes are available in the Sun Java System Application Server 9.1_02 logs.
Sun Java System Application Server 9.1_02

The stack trace contains the following:

[#|2008-07-25T15:42:30.223+0200|SEVERE|sun-appserver9.1|javax.enterprise.system.container.web|_ThreadID=16;_ThreadName=httpSSLWorkerThread-8080-0;_RequestID=d0d49393-9dc2-4f9d-92fe-3884cf057670;|StandardWrapperValve[jsp]: PWC1406: Servlet.service() for servlet jsp threw exception
java.lang.NullPointerException
at org.apache.jsp.userlist_jsp._jspService(userlist_jsp.java from :104)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:93)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:831)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:373)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:470)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:364)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:831)
at org.apache.catalina.core.ApplicationFilterChain.servletService(ApplicationFilterChain.java:411)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:290)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:271)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:202)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:632)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:577)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:94)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:206)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:632)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:577)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:571)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:1080)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:150)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:632)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:577)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:571)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:1080)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:272)
at com.sun.enterprise.web.connector.grizzly.DefaultProcessorTask.invokeAdapter(DefaultProcessorTask.java:637)
at com.sun.enterprise.web.connector.grizzly.DefaultProcessorTask.doProcess(DefaultProcessorTask.java:568)
at com.sun.enterprise.web.connector.grizzly.DefaultProcessorTask.process(DefaultProcessorTask.java:813)
at com.sun.enterprise.web.connector.grizzly.DefaultReadTask.executeProcessorTask(DefaultReadTask.java:341)
at com.sun.enterprise.web.connector.grizzly.DefaultReadTask.doTask(DefaultReadTask.java:263)
at com.sun.enterprise.web.connector.grizzly.DefaultReadTask.doTask(DefaultReadTask.java:214)
at com.sun.enterprise.web.connector.grizzly.TaskBase.run(TaskBase.java:265)
at com.sun.enterprise.web.connector.grizzly.ssl.SSLWorkerThread.run(SSLWorkerThread.java:106)

If someone can please advise me as to what I'm doing wrong, I would greatly appreciate it.

Thanks

Lionel