Question

I have a really strange issue when using hibernate to connect to a MySQLDB and add data.

This is the error I get:

JDBC Driver class not found:
com.mysql.jdbc.Driver

This is how my hibernate.cfg.xml looks like

<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/fpa-webapp</property>
        <property name="hibernate.dialect">org.hibernate.dialect.MySQLInnoDBDialect</property>
        <property name="hibernate.connection.username">root</property>
        <property name="hibernate.connection.password"></property>
        <property name="hbm2ddl.auto">update</property>
        <property name="hibernate.show_sql">true</property>
        <property name="hibernate.format_sql">true</property>
    </session-factory>
</hibernate-configuration>

I dont understand why I see a 500 Error when I navigate to the application; it says that the driver is not found.

HTTP ERROR 500

Problem accessing /fpa-webapp/.
Reason:

Exception constructing service 'ValueEncoderSource': Error invoking

service builder method
org.apache.tapestry5.services.TapestryModule.buildValueEncoderSource(Map,
InvalidationEventHub) (at
TapestryModule.java:2287) (for service
‘ValueEncoderSource’): Error invoking
service contribution method
org.apache.tapestry5.hibernate.HibernateModule.contributeValueEncoderSource(MappedConfiguration,
boolean, HibernateSessionSource,
Session, TypeCoercer, PropertyAccess,
LoggerSource): Exception constructing
service ‘HibernateSessionSource’:
Error invoking service builder method
org.apache.tapestry5.hibernate.HibernateCoreModule.buildHibernateSessionSource(Logger,
List, RegistryShutdownHub) (at
HibernateCoreModule.java:123) (for
service ‘HibernateSessionSource’):
JDBC Driver class not found:
com.mysql.jdbc.Driver

I’m sure the driver is in the class path.

What it could be?

Answer 1

Your driver is not on the classpath.

There are two ways to ensure it’s on the classpath:

1. Add it to the global lib directory. For Tomcat this is TOMCAT_HOME/lib.
2. Include it in the war.

It depends on your requirements which you use.

If you’re going to use Tomcat to manage the connection pool, you’ll need to add it to the TOMCAT_HOME/lib and instead of defining your datasource directly in the hibernate configuration, you’ll reference it via jndi.