Good catch but I think this needs some more investigation. Back in the days Thomas added the DisposableBean call to SimpleMongoDbFactory. Your suggested patch makes a lot of sense but I would like to clean up the behaviour in SimpleMongoDbFactory as must not call close to Mongo instances configured from the outside. Beyond that we should move the setup of the Mongo instance to an afterPropertiesSet() method inside MongoFactoryBean to improve symmetrie for bootstrap and shutdown of the factory class.

I'll include your patch into a fix I'll commit against the original JIRA ticket.

Fixed and deployed to both 1.0.x and 1.1.x branches. Thanks for the contribution!