Question

I have searched on google and stackoverflow for this problem there are several questions but not resulting to particular solution and reason behind the cause. I am doing a project in JSF with context for my project defined in C:\apache-tomcat-6.0.32\conf\Catalina\localhost\.

Also my in my web.xml I have following configuration:

<context-param>
    <description>Database server name</description>
    <param-name>DATABASE</param-name>
    <param-value>MYSQL</param-value>
</context-param>
<resource-ref>
    <description>DB Connection</description>
    <res-ref-name>jdbc/MySqlDS</res-ref-name>
    <res-type>javax.sql.DataSource</res-type>
    <res-auth>Container</res-auth>
</resource-ref>

Now The context file for this project is as follows:

<Context path="/SMS" debug="5" reloadable="true" crossContext="true">
    <Resource name="jdbc/MySqlDS" auth="Container"
        type="javax.sql.DataSource" removeAbandoned="true"
        removeAbandonedTimeout="30" maxActive="100"
        maxIdle="30" maxWait="10000" username="root"
        password=""
        driverClassName="com.mysql.jdbc.Driver"
        url="jdbc:mysql://localhost:3306/rosebud"/>
</Context>

The code in my controller is :

InitialContext initialContext = new InitialContext();
Context envContext  = (Context)initialContext.lookup("java:/comp/env");
javax.sql.DataSource ds = (javax.sql.DataSource) envContext.lookup("jdbc/MySqlDS"); 
java.sql.Connection conn = ds.getConnection();

Here is my stacktrace:

org.apache.tomcat.dbcp.dbcp.SQLNestedException:
Cannot create JDBC driver of class ”
for connect URL ‘null’ at
org.apache.tomcat.dbcp.dbcp.BasicDataSource.createConnectionFactory(BasicDataSource.java:1452)
at
org.apache.tomcat.dbcp.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1371)
at
org.apache.tomcat.dbcp.dbcp.BasicDataSource.getConnection(BasicDataSource.java:1044)
at
com.isys.common.navigation.dao.mysql.TmpNavDAOMySql.getConnection(TmpNavDAOMySql.java:91)
at
com.isys.common.navigation.dao.mysql.TmpNavDAOMySql.populateModels(TmpNavDAOMySql.java:114)
at
com.isys.common.navigation.dao.mysql.TmpNavDAOMySql.populateNavModules(TmpNavDAOMySql.java:19)
at
com.isys.common.navigation.dao.mysql.TmpNavDAOMySqlImpl.populateNavModules(TmpNavDAOMySqlImpl.java:11)
at
com.isys.common.navigation.controller.TmpNavGenerator.init(TmpNavGenerator.java:12)
at
org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1173)
at
org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:993)
at
org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4420)
at
org.apache.catalina.core.StandardContext.start(StandardContext.java:4733)
at
org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)
at
org.apache.catalina.core.StandardHost.start(StandardHost.java:840)
at
org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)
at
org.apache.catalina.core.StandardEngine.start(StandardEngine.java:463)
at
org.apache.catalina.core.StandardService.start(StandardService.java:525)
at
org.apache.catalina.core.StandardServer.start(StandardServer.java:754)
at
org.apache.catalina.startup.Catalina.start(Catalina.java:595)
at
sun.reflect.NativeMethodAccessorImpl.invoke0(Native
Method) at
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown
Source) at
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown
Source) at
java.lang.reflect.Method.invoke(Unknown
Source) at
org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:289)
at
org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)
Caused by:
java.lang.NullPointerException at
sun.jdbc.odbc.JdbcOdbcDriver.getProtocol(Unknown
Source) at
sun.jdbc.odbc.JdbcOdbcDriver.knownURL(Unknown
Source) at
sun.jdbc.odbc.JdbcOdbcDriver.acceptsURL(Unknown
Source) at
java.sql.DriverManager.getDriver(Unknown
Source) at
org.apache.tomcat.dbcp.dbcp.BasicDataSource.createConnectionFactory(BasicDataSource.java:1437)
… 24 more

The configuration works fine if I run tomcat from outside eclipse but fails when ran from inside eclipse. What might be the cause?

Answer 1

Look at the root cause of the exception:

Caused by: java.lang.NullPointerException
    at sun.jdbc.odbc.JdbcOdbcDriver.getProtocol(Unknown Source)
    at sun.jdbc.odbc.JdbcOdbcDriver.knownURL(Unknown Source)
    at sun.jdbc.odbc.JdbcOdbcDriver.acceptsURL(Unknown Source)
    at java.sql.DriverManager.getDriver(Unknown Source)
    at org.apache.tomcat.dbcp.dbcp.BasicDataSource.createConnectionFactory(BasicDataSource.java:1437)
    ... 24 more

This NPE is clearly a bug in the Sun JDBC ODBC bridge driver. It should have handled it more gracefully or have thrown a more self-explaining exception.

But it is at its own a bigger problem that the Tomcat datasource manager is using the Sun JDBC ODBC bridge driver instead of the MySQL JDBC driver which you specified in the driverClassName of the <Resource>! This means that the <Resource> is not correctly been found/interpreted by Tomcat at all. You should be placing the context.xml file in the /META-INF folder of your webapp. Or you should be putting the <Resource> inside the <Context> of the tomcat/conf/context.xml file.