JackRabbit Repository Clean Up

[Bilikiss Kola-Abiola]

I've been doing some work using jackrabbit and I use RepositoryImpl to
initialize and shutdown my repository. I always explicitly call
repository.shutdown() but I've noticed that sometimes there is still a lock
on the repository.
To start the repository I call
        RepositoryConfig repConf = RepositoryConfig.create
(CONFIG_FILE,DIRECTORY);
        repository = RepositoryImpl.create(repConf);
        session = repository.login(context.getCredentials());

and I shut down with
 ( (RepositoryImpl)repository).shutdown();

Any thoughts on this? Is there something I'm doing wrong?
Thanks