public class HibernateUtil {

    /** Holds reference to session factory */
    private static final SessionFactory sessionFactory;

    static {
        try {
            final Configuration configuration = new Configuration();
            sessionFactory = configuration.configure().buildSessionFactory();
        } catch (Throwable ex) {
            ex.printStackTrace();
            throw new ExceptionInInitializerError(ex);
        }
    }

    /**
     * Get session factory.
     *
     * @return session factory
     */
    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }
}

  <property name="hibernate.c3p0.min_size">5</property>
  <property name="hibernate.c3p0.max_size">20</property>
  <property name="hibernate.c3p0.timeout">300</property>
  <property name="hibernate.c3p0.max_statements">50</property>
  <property name="hibernate.c3p0.idle_test_period">3000</property>

<property name="c3p0.max_size">100</property>
<property name="c3p0.min_size">10</property>
<property name="c3p0.timeout">10</property> <!-- seconds -->
<property name="c3p0.acquireRetryAttempts">30</property>
<property name="c3p0.acquireIncrement">5</property>
<property name="c3p0.idleConnectionTestPeriod">300</property>
<property name="c3p0.initialPoolSize">20</property>
<property name="c3p0.maxPoolSize">100</property>
<property name="c3p0.maxIdleTime">300</property>
<property name="c3p0.maxStatements">50</property>
<property name="c3p0.minPoolSize">10</property>