If you suddenly receive a warning stating “unclosed connection, forgot to call close() on your Session” from Hibernate, and you are utilizing OpenSessionInViewFilter to manage your Hibernate sessions, it is crucial to verify that the filter mapping of OpenSessionInViewFilter in web.xml precedes any other filter mappings, such as Acegi Security Filters. This is particularly important because those other mappings might trigger database operations depending on the Hibernate session. If there is no open session, they will likely open one, potentially leaving it open. Normally, it is the responsibility of OpenSessionInViewFilter to close Hibernate sessions at the end of the response.
Just a simple reminder!