Following are some possible reasons why Hibernate might not be closing connections:
 

o You are forgetting to call Session.close().
This is the most common cause. Consider carefully how you are handling sessions.
Are you sure you create only one Session per transaction? Are you certain you close the
Session even if an exception occurs (ie. in a finally block). Hibernate issues a warning
in the log when an unclosed session is garbage collected, so
looking there is a good place to start.

Session s = sf.openSession();
 try {
 // do some work
s.connection().commit();
 } catch (Exception e) {
 s.connection().rollback();
 } finally {
 s.close().close(); //close the session and user-supplied JDBC connection
}
 

o Hibernate is doing connection pooling.

Which ConnnectionProvider are you using? If its not DatasourceConnectionProvider, then
it is probably doing connection pooling. This can cause problems in certain environments.
Pooling may be disabled for DriverManagerConnectionProvider by setting
hibernate.connection.pool_size=0 in hibernate.properties.

Back to top