Rule Definition
It is very important to define a connection pool to increase database access performances. Hibernate's own connection pooling algorithm is quite rudimentary. It is intended to help you get started and is not intended for use in a production system or even for performance testing. Use a third party pool for best performance and stability.

Remediation
Use a third party connection pool like: * c3p0 - http://sourceforge.net/projects/c3p0 - Distributed with Hibernate * Apache DBCP - http://jakarta.apache.org/commons/dbcp/ - Apache Pool * Proxool - http://proxool.sourceforge.net/ - JDBC Pooling Wrapper * a connection pool from an external vendor

Violation Code Sample

---> hibernate.cfg.xml
...
<hibernate-configuration>
    <session-factory name="java:comp/env/hibernate/SessionFactory">
       ...
        <property name="connection.pool_size">10</property> // VIOLATION
...

---> or in hibernate.properties
hibernate.connection.pool_size = 10 // VIOLATION

Fixed Code Sample

---> hibernate.cfg.xml
...
<hibernate-configuration>
    <!-- a SessionFactory instance listed as /jndi/name -->
    <session-factory
        name="java:comp/env/hibernate/SessionFactory">
        <!-- properties -->
        <property name="connection.datasource">my/first/datasource</property> // FIXED
     ...
    </session-factory>
</hibernate-configuration>

---> or in hibernate.properties
...
hibernate.connection.datasource = my/first/datasource
...

http://www.hibernate.org/hib_docs/reference/en/html/session-configuration.html http://www.informit.com/articles/article.asp?p=353736&seqNum=4&rl=1 Hibernate in Action (ISBN 1932394-15-X) p 45