java mysql hibernate connection-pooling c3p0

Something wrong with Hibernate DB connection pooler c3p0

since last post, did all the changes suggested but this problem still haunts me. Here's the error i get:

Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet successfully received from the server was 44,499,102 milliseconds ago.

here's my hibernate.cfg.xml

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
<session-factory>

    <property name="hibernate.connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</property>        
    <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>        
    <property name="connection.autoReconnect"> true</property>
    <property name="connection.autoReconnectForPools">true</property>
    <property name="connection.is-connection-validation-required">true</property>

    <property name="hibernate.c3p0.acquire_increment">5</property> 
    <property name="hibernate.c3p0.max_size">150</property>
    <property name="hibernate.c3p0.max_statements">0</property>
    <property name="hibernate.c3p0.min_size">10</property>
    <property name="hibernate.c3p0.timeout">100</property> <!-- seconds --> 
    <property name="hibernate.c3p0.idle_test_period">30</property> <!-- seconds --> 

    <property name="hibernate.connection.url">jdbc:mysql://!secret!autoReconnect=true</property>
    <property name="hibernate.connection.username">!secret!</property>
    <property name="hibernate.connection.password">!secret!</property>


    <!-- <property name="hibernate.connection.pool_size">10</property> -->

    <property name="show_sql">true</property>
    <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
    <property name="hibernate.hbm2ddl.auto">update</property>
    <property name="current_session_context_class">thread</property>

    <!-- Mapping files -->
    <mapping resource="mappings.hbm.xml"/>
</session-factory>
</hibernate-configuration>

and c3p0.properties

c3p0.preferredTestQuery=select 1 from dual
c3p0.maxConnectionAge=3600
c3p0.testConnectionOnCheckin=true
c3p0.testConnectionOnCheckout=true
c3p0.acquireRetryDelay=1000
c3p0.acquireRetryAttempts=30
c3p0.breakAfterAcquireFailure=false
c3p0.idleConnectionTestPeriod=100

Solution

As for me, you're incorrectly configured c3p0.

Properties like c3p0.preferredTestQuery must be located at c3p0.properties file from your classpath (e.g. WEB-INF/classes).

Below is my example of c3p0.properties file that work nice for Oracle:

c3p0.preferredTestQuery=SELECT 1 from dual
c3p0.maxConnectionAge=3600
c3p0.testConnectionOnCheckout=true
c3p0.acquireRetryDelay=1000
c3p0.acquireRetryAttempts=30
c3p0.breakAfterAcquireFailure=false