Hibernate will be connecting to the database on behalf of your application, so it needs to know how to obtain connections. For this tutorial we will be using a standalone connection pool (as opposed to a javax.sql.DataSource ). Hibernate comes with support for two third-party open source JDBC connection pools: c3p0 and proxool .
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>