I am using a ComboPooledDataSource with a minimum pool size of 1.  I am calling DataSources.destroy(dataSource) to close the pool.  However, after this call returns, there is still an active connection to the database.  It appears that the connections in the pool are not closed when the pool is closed (at least not synchronously).  How can I force the pool to immediately close all connections to the database or block until they have all been closed?