Connection Pool setting for JPA

Make sure that the following is set in the persistence.xml file

<!-- Important -->

<property name="hibernate.connection.provider_class"

  value="org.hibernate.connection.C3P0ConnectionProvider" />

<property name="hibernate.c3p0.max_size" value="100" />

<property name="hibernate.c3p0.min_size" value="0" />

<property name="hibernate.c3p0.acquire_increment" value="1" />

<property name="hibernate.c3p0.idle_test_period" value="300" />

<property name="hibernate.c3p0.max_statements" value="0" />

<property name="hibernate.c3p0.timeout" value="100" />

Ensure that the connection provider is set and all properties of connection pool are prefixed with "hibernate.

The easy way to verify is that you should see from the log files the following statements

INFO: Initializing c3p0-0.9.1 [built 16-January-2007 14:46:42; debug? true; trace: 10]

com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource getPoolManager

INFO: Initializing c3p0 pool... com.mchange.v2.c3p0.PoolBackedDataSource@f3a94e12 [     connectionPoolDataSource ->