C3P0: Tried to check-in a foreign resource!

Earlier today I encountered the following stack trace whilst using C3P0 and Hibernate:

com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool - An Exception occurred while trying to check a PooledConection into a ResourcePool.
com.mchange.v2.resourcepool.ResourcePoolException: ResourcePool [BROKEN!]: Tried to check-in a foreign resource!
	at com.mchange.v2.resourcepool.BasicResourcePool.checkinResource(BasicResourcePool.java:657)
	at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$ConnectionEventListenerImpl.doCheckinResource(C3P0PooledConnectionPool.java:636)
	at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$ConnectionEventListenerImpl.connectionClosed(C3P0PooledConnectionPool.java:630)
	at com.mchange.v2.c3p0.util.ConnectionEventSupport.fireConnectionClosed(ConnectionEventSupport.java:55)
	at com.mchange.v2.c3p0.impl.NewPooledConnection.fireConnectionClosed(NewPooledConnection.java:510)
	at com.mchange.v2.c3p0.impl.NewPooledConnection.markClosedProxyConnection(NewPooledConnection.java:381)
	at com.mchange.v2.c3p0.impl.NewProxyConnection.close(NewProxyConnection.java:1246)
	at org.hibernate.connection.C3P0ConnectionProvider.closeConnection(C3P0ConnectionProvider.java:92)
	at org.hibernate.jdbc.ConnectionManager.closeConnection(ConnectionManager.java:474)
	at org.hibernate.jdbc.ConnectionManager.aggressiveRelease(ConnectionManager.java:429)
	at org.hibernate.jdbc.ConnectionManager.afterTransaction(ConnectionManager.java:316)
	at org.hibernate.jdbc.JDBCContext.afterNontransactionalQuery(JDBCContext.java:268)
	at org.hibernate.impl.SessionImpl.afterOperation(SessionImpl.java:444)
	at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1153)
	at org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)

Apologies for the scroll bars… but hopefully this is indexed neatly by Google to help others!

After a bit of investigation it turned out this was due to a multi-threading issue and the solution can be summarised quite neatly:

never shut down Hibernate before all threads have finished what they’re doing (if they are using Hibernate)

Otherwise, you may get the above exception (or an equally unhelpful exception).

This entry was posted on Wednesday, March 25th, 2009 at 2:34 pm and is filed under Coding / Tech. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

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