Hibernate version: 3.2.4.sp1

Name and version of the database you are using: MySQL 5.0.41-community-nt

Hibernate configuration (c3po part):
<property name="c3p0.min_size">5</property>
<property name="c3p0.max_size">10</property>
<property name="c3p0.timeout">300</property>
<property name="c3p0.max_statements">50</property>
<property name="c3p0.idle_test_period">3000</property>

Q1: When I set the debug level to at least DEBUG, when I close the SsessionFactory.close(), I get the following debug output:

Full stack trace of any exception that occurs:

14:57:07,2145p AbstractPoolBackedDataSource:417 - com.mchange.v2.c3p0.PoolBackedDataSource@12ad19e has been closed.
java.lang.Exception: DEBUG STACK TRACE for PoolBackedDataSource.close().
at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.close(AbstractPoolBackedDataSource.java:417)
at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.close(AbstractPoolBackedDataSource.java:429)
at com.mchange.v2.c3p0.DataSources.destroy(DataSources.java:359)
at com.mchange.v2.c3p0.DataSources.destroy(DataSources.java:335)
at org.hibernate.connection.C3P0ConnectionProvider.close(C3P0ConnectionProvider.java:182)
at org.hibernate.impl.SessionFactoryImpl.close(SessionFactoryImpl.java:803)
at hb.test.HibernateUtil.shutdown(HibernateUtil.java:27)
at Main.main(Main.java:14)
14:57:07,2245p NewPooledConnection:491 - com.mchange.v2.c3p0.impl.NewPooledConnection@1bbd23f closed by a client.
java.lang.Exception: DEBUG -- CLOSE BY CLIENT STACK TRACE
at com.mchange.v2.c3p0.impl.NewPooledConnection.close(NewPooledConnection.java:491)
at com.mchange.v2.c3p0.impl.NewPooledConnection.close(NewPooledConnection.java:191)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.destroyResource(C3P0PooledConnectionPool.java:470)
at com.mchange.v2.resourcepool.BasicResourcePool$1DestroyResourceTask.run(BasicResourcePool.java:964)
at com.mchange.v2.resourcepool.BasicResourcePool.destroyResource(BasicResourcePool.java:989)
at com.mchange.v2.resourcepool.BasicResourcePool.access$100(BasicResourcePool.java:32)
at com.mchange.v2.resourcepool.BasicResourcePool$5.run(BasicResourcePool.java:1174)
14:57:07,2245p C3P0PooledConnectionPool:476 - Successfully destroyed PooledConnection: com.mchange.v2.c3p0.impl.NewPooledConnection@1bbd23f
14:57:07,2245p BasicResourcePool:967 - Successfully destroyed resource: com.mchange.v2.c3p0.impl.NewPooledConnection@1bbd23f
14:57:07,2245p BasicResourcePool:962 - Preparing to destroy resource: com.mchange.v2.c3p0.impl.NewPooledConnection@16f0be8
14:57:07,2245p C3P0PooledConnectionPool:468 - Preparing to destroy PooledConnection: com.mchange.v2.c3p0.impl.NewPooledConnection@16f0be8
14:57:07,2345p NewPooledConnection:491 - com.mchange.v2.c3p0.impl.NewPooledConnection@16f0be8 closed by a client.
java.lang.Exception: DEBUG -- CLOSE BY CLIENT STACK TRACE
at com.mchange.v2.c3p0.impl.NewPooledConnection.close(NewPooledConnection.java:491)
at com.mchange.v2.c3p0.impl.NewPooledConnection.close(NewPooledConnection.java:191)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.destroyResource(C3P0PooledConnectionPool.java:470)
at com.mchange.v2.resourcepool.BasicResourcePool$1DestroyResourceTask.run(BasicResourcePool.java:964)
at com.mchange.v2.resourcepool.BasicResourcePool.destroyResource(BasicResourcePool.java:989)
at com.mchange.v2.resourcepool.BasicResourcePool.access$100(BasicResourcePool.java:32)
at com.mchange.v2.resourcepool.BasicResourcePool$5.run(BasicResourcePool.java:1174)
14:57:07,2345p C3P0PooledConnectionPool:476 - Successfully destroyed PooledConnection: com.mchange.v2.c3p0.impl.NewPooledConnection@16f0be8
14:57:07,2345p BasicResourcePool:967 - Successfully destroyed resource: com.mchange.v2.c3p0.impl.NewPooledConnection@16f0be8
14:57:07,2345p BasicResourcePool:962 - Preparing to destroy resource: com.mchange.v2.c3p0.impl.NewPooledConnection@19e8f17
14:57:07,2345p C3P0PooledConnectionPool:468 - Preparing to destroy PooledConnection: com.mchange.v2.c3p0.impl.NewPooledConnection@19e8f17
14:57:07,2445p NewPooledConnection:491 - com.mchange.v2.c3p0.impl.NewPooledConnection@19e8f17 closed by a client.
java.lang.Exception: DEBUG -- CLOSE BY CLIENT STACK TRACE
at com.mchange.v2.c3p0.impl.NewPooledConnection.close(NewPooledConnection.java:491)
at com.mchange.v2.c3p0.impl.NewPooledConnection.close(NewPooledConnection.java:191)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.destroyResource(C3P0PooledConnectionPool.java:470)
at com.mchange.v2.resourcepool.BasicResourcePool$1DestroyResourceTask.run(BasicResourcePool.java:964)
at com.mchange.v2.resourcepool.BasicResourcePool.destroyResource(BasicResourcePool.java:989)
at com.mchange.v2.resourcepool.BasicResourcePool.access$100(BasicResourcePool.java:32)
at com.mchange.v2.resourcepool.BasicResourcePool$5.run(BasicResourcePool.java:1174)
14:57:07,2445p C3P0PooledConnectionPool:476 - Successfully destroyed PooledConnection: com.mchange.v2.c3p0.impl.NewPooledConnection@19e8f17
14:57:07,2445p BasicResourcePool:967 - Successfully destroyed resource: com.mchange.v2.c3p0.impl.NewPooledConnection@19e8f17
14:57:07,2445p BasicResourcePool:962 - Preparing to destroy resource: com.mchange.v2.c3p0.impl.NewPooledConnection@164dbd5
14:57:07,2445p C3P0PooledConnectionPool:468 - Preparing to destroy PooledConnection: com.mchange.v2.c3p0.impl.NewPooledConnection@164dbd5
14:57:07,2445p NewPooledConnection:491 - com.mchange.v2.c3p0.impl.NewPooledConnection@164dbd5 closed by a client.
java.lang.Exception: DEBUG -- CLOSE BY CLIENT STACK TRACE
at com.mchange.v2.c3p0.impl.NewPooledConnection.close(NewPooledConnection.java:491)
at com.mchange.v2.c3p0.impl.NewPooledConnection.close(NewPooledConnection.java:191)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.destroyResource(C3P0PooledConnectionPool.java:470)
at com.mchange.v2.resourcepool.BasicResourcePool$1DestroyResourceTask.run(BasicResourcePool.java:964)
at com.mchange.v2.resourcepool.BasicResourcePool.destroyResource(BasicResourcePool.java:989)
at com.mchange.v2.resourcepool.BasicResourcePool.access$100(BasicResourcePool.java:32)
at com.mchange.v2.resourcepool.BasicResourcePool$5.run(BasicResourcePool.java:1174)
14:57:07,2445p C3P0PooledConnectionPool:476 - Successfully destroyed PooledConnection: com.mchange.v2.c3p0.impl.NewPooledConnection@164dbd5
14:57:07,2445p BasicResourcePool:967 - Successfully destroyed resource: com.mchange.v2.c3p0.impl.NewPooledConnection@164dbd5
14:57:07,2445p BasicResourcePool:962 - Preparing to destroy resource: com.mchange.v2.c3p0.impl.NewPooledConnection@3411a
14:57:07,2445p C3P0PooledConnectionPool:468 - Preparing to destroy PooledConnection: com.mchange.v2.c3p0.impl.NewPooledConnection@3411a
14:57:07,2545p NewPooledConnection:491 - com.mchange.v2.c3p0.impl.NewPooledConnection@3411a closed by a client.
java.lang.Exception: DEBUG -- CLOSE BY CLIENT STACK TRACE
at com.mchange.v2.c3p0.impl.NewPooledConnection.close(NewPooledConnection.java:491)
at com.mchange.v2.c3p0.impl.NewPooledConnection.close(NewPooledConnection.java:191)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.destroyResource(C3P0PooledConnectionPool.java:470)
at com.mchange.v2.resourcepool.BasicResourcePool$1DestroyResourceTask.run(BasicResourcePool.java:964)
at com.mchange.v2.resourcepool.BasicResourcePool.destroyResource(BasicResourcePool.java:989)
at com.mchange.v2.resourcepool.BasicResourcePool.access$100(BasicResourcePool.java:32)
at com.mchange.v2.resourcepool.BasicResourcePool$5.run(BasicResourcePool.java:1174)
14:57:07,2545p C3P0PooledConnectionPool:476 - Successfully destroyed PooledConnection: com.mchange.v2.c3p0.impl.NewPooledConnection@3411a
14:57:07,2545p BasicResourcePool:967 - Successfully destroyed resource: com.mchange.v2.c3p0.impl.NewPooledConnection@3411a

Whay does this exactly happen? It's worth noticing that everything is correctly saved and read frmo the database in the meantime.

Q2: In the log output when Hibernate start, I see these:
15:05:32,8115p C3P0ConnectionProvider:210 - Both hibernate-style property 'hibernate.c3p0.max_size' and c3p0-style property 'c3p0.max_size' have been set in hibernate.properties. Hibernate-style property 'hibernate.c3p0.max_size' will be used and c3p0-style property 'c3p0.max_size' will be ignored!
15:05:32,8115p C3P0ConnectionProvider:210 - Both hibernate-style property 'hibernate.c3p0.min_size' and c3p0-style property 'c3p0.min_size' have been set in hibernate.properties. Hibernate-style property 'hibernate.c3p0.min_size' will be used and c3p0-style property 'c3p0.min_size' will be ignored!
15:05:32,8115p C3P0ConnectionProvider:210 - Both hibernate-style property 'hibernate.c3p0.timeout' and c3p0-style property 'c3p0.timeout' have been set in hibernate.properties. Hibernate-style property 'hibernate.c3p0.timeout' will be used and c3p0-style property 'c3p0.timeout' will be ignored!
15:05:32,8115p C3P0ConnectionProvider:210 - Both hibernate-style property 'hibernate.c3p0.idle_test_period' and c3p0-style property 'c3p0.idle_test_period' have been set in hibernate.properties. Hibernate-style property 'hibernate.c3p0.idle_test_period' will be used and c3p0-style property 'c3p0.idle_test_period' will be ignored!
15:05:32,8115p C3P0ConnectionProvider:210 - Both hibernate-style property 'hibernate.c3p0.max_statements' and c3p0-style property 'c3p0.max_statements' have been set in hibernate.properties. Hibernate-style property 'hibernate.c3p0.max_statements' will be used and c3p0-style property 'c3p0.max_statements' will be ignored!

Why does this happen? I only use c3po-style properties, and why are they said to be ignored? I don't even have a hibernate.properties file with those hibernate-style settings.