Another problem which may cause this kind of exception is that your JDBC driver doesn’t exists in the classpath …
<!DOCTYPE hibernate-configuration PUBLIC “-//Hibernate/Hibernate Configuration DTD 3.0//EN” “http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd”> <hibernate-configuration> <session-factory> <!– datasource config –> <property name=”connection.url”>jdbc:mysql://localhost:3306/db?useUnicode=true&characterEncoding=UTF-8&autoReconnect=true</property> <property name=”hibernate.dialect”>org.hibernate.dialect.MySQL5InnoDBDialect</property> <property name=”connection.driver_class”>com.mysql.jdbc.Driver</property> <property name=”connection.username”>user</property> <property name=”connection.password”>pass</property> <!– c3p0 config http://www.hibernate.org/214.html –> <property name=”connection.provider_class”>org.hibernate.connection.C3P0ConnectionProvider</property> <property name=”hibernate.c3p0.acquire_increment”>1</property> <property name=”hibernate.c3p0.idle_test_period”>60</property> <property name=”hibernate.c3p0.min_size”>1</property> <property name=”hibernate.c3p0.max_size”>2</property> <property name=”hibernate.c3p0.max_statements”>50</property> <property name=”hibernate.c3p0.timeout”>0</property> <property name=”hibernate.c3p0.acquireRetryAttempts”>1</property> <property name=”hibernate.c3p0.acquireRetryDelay”>250</property> <property name=”hibernate.show_sql”>true</property> <property name=”hibernate.use_sql_comments”>true</property> <property name=”hibernate.transaction.factory_class”>org.hibernate.transaction.JDBCTransactionFactory</property> <property name=”hibernate.current_session_context_class”>thread</property> … Read more
You’ve done good research. I’d say, go ahead with BoneCP. Some years ago I would have suggested c3p0, but it has currently some open and unresolved issues as well. Too bad, actually. The BoneCP author is by the way also active here at SO.
You can monitor your connection pool(s) via JMX. From the documentation: Configuring and Managing c3p0 via JMX If JMX libraries and a JMX MBeanServer are available in your environment (they are include in JDK 1.5 and above), you can inspect and configure your c3p0 datasources via a JMX administration tool (such as jconsole, bundled with … Read more
C3PO and DBCP development have stalled mostly because they are mature. I have seen both of these drivers be able to support hundreds of transactions per second. The Tomcat pool is a reworked & updated DBCP driver. MyBatis 3.0 also contains it’s own pooling implementation which, based on code inspection, seems solid. Finally, there’s BoneCP … Read more
DBCP is out of date and not production grade. Some time back we conducted an in-house analysis of the two, creating a test fixture which generated load and concurrency against the two to assess their suitability under real life conditions. DBCP consistently generated exceptions into our test application and struggled to reach levels of performance … Read more