org.apache.tomcat.dbcp.dbcp.SQLNestedException:

[bhallarahul]

hello everyone
i have wrote a code but it shows "org.apache.tomcat.dbcp.dbcp.SQLNestedException:" error
org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot create JDBC driver of class '' for connect URL 'null'
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1150)
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.getConnection(BasicDataSource.java:880)
at listener.MyContextListener.contextInitialized(Unknown Source)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:3972)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4467)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:791)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:771)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:526)
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1041)
at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:964)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:502)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1277)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:321)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:722)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443)
at org.apache.catalina.core.StandardService.start(StandardService.java:516)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:710)
at org.apache.catalina.startup.Catalina.start(Catalina.java:593)
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.createDataSource(BasicDataSource.java:1143)
... 26 more

package listener;

import java.sql.Connection;
import java.sql.SQLException;

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.sql.DataSource;

public class MyContextListener implements ServletContextListener {
	Connection conn=null;

	@Override
	public void contextDestroyed(ServletContextEvent arg) {
		// TODO Auto-generated method stub
		try {
			conn.close();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	}

	@Override
	public void contextInitialized(ServletContextEvent arg) {
		// TODO Auto-generated method stub
		Context ctx = null;
		try {
			ctx = new InitialContext();
		} catch (NamingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		DataSource ds = null;
		try {
			ds = (DataSource)ctx.lookup("java:comp/env/jdbc/TestMZ");

		} catch (NamingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
		if(ds!=null)
		{
			try {
				conn=ds.getConnection();
								
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		if(conn!=null)
		{
			arg.getServletContext().setAttribute("connection", conn);
		}
		
	}
}

context.xml
<?xml version="1.0" encoding="UTF-8"?>
<context>
<WatchedResource>WEB-INF/web.xml</WatchedResource>

<Resouce name="jdbc/TestMZ" auth="Container" type="javax.sql.DataSource"
maxActive="100" maxIdle="30" maxWait="1000"
username="rl" password="rl" driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/TestMZ"/>

</Context>
<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<display-name>usingJNDI</display-name>

<resource-ref>
<description>DB Connection</description>
<res-ref-name>jdbc/TestMZ</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
<listener>
<listener-class>listener.MyContextListener</listener-class>
</listener>

<servlet>
<description>
</description>
<display-name>DisplayData</display-name>
<servlet-name>DisplayData</servlet-name>
<servlet-class>
secure.DisplayData</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>DisplayData</servlet-name>
<url-pattern>/pages/display</url-pattern>
</servlet-mapping>

</web-app>

[stultuske]

you're getting a nullpointerexception in your contextInitialized method.
start with a System.out.println for your arg variable, to check if that passes what you think it is passing.
add to each
e.printStackTrace()
a precision:
System.out.println("error in first catch");
e.printStackTrace();
..
System.out.println("error in second catch");
e.printStackTrace();

and you'll quickly know where the error occurs, that 'll make it easier to improve the code.

[bhallarahul]

thnks for the reply. I already use what u said and error comes from line number 50 ie

conn=ds.getConnection();

[bhallarahul]

hello i solve above problem on my own
problem is in given statement :
"ds = (DataSource)ctx.lookup("java:comp/env/jdbc/TestMZ");"
i wrote env which is to be evn
thank you