Error while getting a Connection from a Datasource

Question

hi all, m using netbeans to design a web app. it got to the point of connecting to a mysql database, i tried to follow the recommendation of using a datasource instead, and i edited the META-INF\context.xml and
WEB-INF\web.xml as follows respectively.
Here is a copy of context.xml
<?xml version="1.0" encoding="UTF-8"?>
<Context path="/MyOnlineStore">
<Resource name="jdbc/StoreDB"
type="javax.sql.DataSource"
auth="Container"
/>
<ResourceParams name="jdbc/StoreDB">
<parameter>
<name>username</name>
<value>root</value>
</parameter>
<parameter>
<name>password</name>
<value>stephanie</value>
</parameter>
<parameter>
<name>driverClassName</name>
<value>com.mysql.jdbc.Driver</value>
</parameter>
<parameter>
<name>url</name>
<value>jdbc:mysql://localhost:3306/mystore?autoReconnect=true</value>
</parameter>
</ResourceParams>
</Context>
and here is a copy of web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<servlet-name>controller</servlet-name>
<servlet-class>com.obinna.servlets.ControllerServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>controller</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>controller</servlet-name>
<url-pattern>/controller</url-pattern>
</servlet-mapping>
<session-config>
<session-timeout>
30
</session-timeout>
</session-config>
<welcome-file-list>
<welcome-file>controller</welcome-file>
</welcome-file-list>
<resource-ref>
<res-ref-name>jdbc/StoreDB</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
</web-app>
and here is a fragment of a helper class i use to retrieve connections
public class StoreJDBCHelper {
private DataSource _dataSource;
public StoreJDBCHelper() throws NamingException
Context context = new InitialContext();
Context applicationEnv = (Context)context.lookup("java:comp/env");
_dataSource = (DataSource)applicationEnv.lookup("jdbc/StoreDB");
public Connection getConnection() throws SQLException
return _dataSource.getConnection();
each time i call getConnection() from another class i get this exception
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 com.obinna.processingcommands.StoreJDBCHelper.getConnection(StoreJDBCHelper.java:33)
at com.obinna.processingcommands.CategoryProcessingCommand.getCategoryDB(CategoryProcessingCommand.java:85)
at com.obinna.processingcommands.CategoryProcessingCommand.getOrCreateCategory(CategoryProcessingCommand.java:58)
at com.obinna.processingcommands.CategoryProcessingCommand.execute(CategoryProcessingCommand.java:47)
at com.obinna.servlets.ControllerServlet.processRequest(ControllerServlet.java:63)
at com.obinna.servlets.ControllerServlet.doPost(ControllerServlet.java:90)
at com.obinna.servlets.ControllerServlet.doGet(ControllerServlet.java:78)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:390)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.lang.NullPointerException
at sun.jdbc.odbc.JdbcOdbcDriver.getProtocol(JdbcOdbcDriver.java:507)
at sun.jdbc.odbc.JdbcOdbcDriver.knownURL(JdbcOdbcDriver.java:476)
at sun.jdbc.odbc.JdbcOdbcDriver.acceptsURL(JdbcOdbcDriver.java:307)
at java.sql.DriverManager.getDriver(DriverManager.java:253)
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1143)
... 25 more
please what can i do.
thanks.

Answer 1

Caused by: java.lang.NullPointerException
at sun.jdbc.odbc.JdbcOdbcDriver.getProtocol(JdbcOdbcDriver.java:507)
at sun.jdbc.odbc.JdbcOdbcDriver.knownURL(JdbcOdbcDriver.java:476)
at sun.jdbc.odbc.JdbcOdbcDriver.acceptsURL(JdbcOdbcDriver.java:307)
at java.sql.DriverManager.getDriver(DriverManager.java:253)
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1143)
... 25 moreDBCP is trying to create a datasource for you. It has the MySQL JDBC URL which you specified (jdbc:mysql://localhost:3306/mystore?autoReconnect=true) and is trying to find a matching driver. It scans all drivers which are loaded and registered in the DriverManager. The JDBC-ODBC bridge driver is apparently also loaded somehow and while testing the MySQL URL on this driver, the driver is throwing a NullPointerException while getting the protocol.
This look like one more bug in the JDBC-ODBC bridge -which is already soo full of unfixed bugs-. So to get this problem solved either remove the JDBC-ODBC bridge driver from your application, or upgrade it to a newer version without this bug (if any exist), or change the Tomcat resource configuration that no one datasource is actually using the JDBC-ODBC bridge driver, so that this driver won't get loaded and registered by the DriverManager.