Hibernate/Spring: Lots (thousands) of open connections the database
tcp6       0      0 ************:53547       ************:3306        TIME_WAIT   0          0           -
tcp6       0      0 ************:53595       ************:3306        TIME_WAIT   0          0           -
tcp6       0      0 ************:53645       ************:3306        TIME_WAIT   0          0           -
tcp6       0      0 ************:34986       ************:3306        TIME_WAIT   0          0           -
tcp6       0      0 ************:53669       ************:3306        TIME_WAIT   0          0           -
tcp6       0      0 ************:53710       ************:3306        TIME_WAIT   0          0           -
tcp6       0      0 ************:53757       ************:3306        TIME_WAIT   0          0           -
tcp6       0      0 ************:53716       ************:3306        TIME_WAIT   0          0           -
tcp6       0      0 ************:53627       ************:3306        TIME_WAIT   0          0           -
tcp6       0      0 ************:53752       ************:3306        TIME_WAIT   0          0           -
tcp6       0      0 ************:53505       ************:3306        TIME_WAIT   0          0           -
tcp6       0      0 ************:53549       ************:3306        TIME_WAIT   0          0           -
tcp6       0      0 ************:35185       ************:3306        TIME_WAIT   0          0           -
tcp6       0      0 ************:53604       ************:3306        TIME_WAIT   0          0           -
tcp6       0      0 ************:35331       ************:3306        TIME_WAIT   0          0           -
tcp6       0      0 ************:53488       ************:3306        TIME_WAIT   0          0           -
tcp6       0      0 ************:34938       ************:3306        TIME_WAIT   0          0           -
tcp6       0      0 ************:34987       ************:3306        TIME_WAIT   0          0           -
tcp6       0      0 ************:53695       ************:3306        TIME_WAIT   0          0           -
tcp6       0      0 ************:35380       ************:3306        TIME_WAIT   0          0           -
tcp6       0      0 ************:53651       ************:3306        TIME_WAIT   0          0           -

<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
    <property name="driverClassName">
        <value>com.mysql.jdbc.Driver</value>
    </property>
    <property name="url">
        <value>jdbc:mysql://************:3306/********</value>
    </property>
    <property name="username">
        <value>********</value>
    </property>
    <property name="password">
        <value>********</value>
    </property>
</bean>

<bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
        <property name="dataSource">
            <ref bean="dataSource" />
        </property>
        <property name="configLocation">
            <value>WEB-INF/hibernate.hbm.xml</value>
        </property>
        <property name="configurationClass">
            <value>org.hibernate.cfg.AnnotationConfiguration</value>
        </property>
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</prop>
                <prop key="hibernate.jdbc.batch_size">0</prop>
                <prop key="hibernate.show_sql">false</prop>
                <prop key="hibernate.bytecode.provider">cglib</prop>
                <prop key="hibernate.hbm2ddl.auto">update</prop>
            </props>
        </property>
        <property name="eventListeners">
            <map>
                <entry key="save-update" value-ref="saveUpdateEventListener" />
            </map>
        </property>
    </bean>

    <bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
        <property name="sessionFactory" ref="sessionFactory" />
    </bean>

Hibernate will obtain and pool connections using java.sql.DriverManager if you set the following properties:

Table 3.1. Hibernate JDBC Properties

Property name                       Purpose
hibernate.connection.driver_class   JDBC driver class
hibernate.connection.url            JDBC URL
hibernate.connection.username       database user
hibernate.connection.password       database user password
hibernate.connection.pool_size      maximum number of pooled connections