Hibernate version: 3.2.5ga, hibernate-c3p0 3.3.0ga
c3p0 version: 0.9.1.2
Tomcat version: 6.0.18

Hibernate.cfg.xml mapping:
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hibernate.connection.datasource">java:comp/env/jdbc/TESTDB</property>
<property name="hibernate.connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</property>

context.xml

<context>
<ResourceLink name="jdbc/TESTDB" global="jdbc/TESTDB" type="javax.sql.DataSource" />
</context>

Global resource in server.xml
<Resource auth="Container"
description="DB Connection"
driverClass="org.gjt.mm.mysql.Driver"
maxPoolSize="4" minPoolSize="2" acquireIncrement="1"
name="jdbc/TESTDB" user="rp_dbo" password="darmis"
factory="org.apache.naming.factory.BeanFactory"
type="com.mchange.v2.c3p0.ComboPooledDataSource"
jdbcUrl="jdbc:mysql://localhost:3306/testdb" />


Stacktrace:

15:18:19,460 INFO C3P0ConnectionProvider:81 - C3P0 using driver: null at URL: null
15:18:19,460 INFO C3P0ConnectionProvider:82 - Connection properties: {}
15:18:19,460 INFO C3P0ConnectionProvider:85 - autocommit mode: false
15:18:19,460 WARN C3P0ConnectionProvider:88 - No JDBC Driver class was specified by property hibernate.connection.driver_class

Problem:
When configureing Hibernate to use C3P0ConnectionProvider instead of default connectionprovider it seems like Hibernate does not find my configured datasource.

If I remove C3P0ConnectionProvider from my hibernate configuration file, hibernate will find my resource and my test application can handle database transactions. When I try to use C3P0 by adding hibernate.connection.provicer_class C3P0ConnectionProvider it fails to find my datasource.

If I use C3P0ConnectionProvider and configure my datasource with driver_class, url, username and password in my hibernate config file. Hibernate will use C3P0 and it all works fine. So it seems like C3P0ConnectionProvider cannot be configured to use datasource configured in tomcat.

Any idea what i’m doing wrong?

If you have a DataSource in JNDI there's no need to tell Hibernate to use C3P0. By providing the C3P0 configuration, you're telling Hibernate to manage an instance of C3P0 and it is trying to do so, but missing other key configuration. Remove hibernate.connection.provider_class and you'll be OK (if you have a DataSource already). If not, then remove the .datasource property and configure C3P0 as per the Hibernate manual.

Thank you!

That makes sense. I have now configured C3P0 properties in my resource definition in tomcat (server.xml). Hibernate automatic detects that my JNDI resource is configured with C3P0 without C3P0ConnectionProvider.

My connection pool works fine now. Thank you cbredsen!