code: public void removeSessionProvider(Object key)
     {
        if (providers.containsKey(key))
        {
           getSessionProvider(key).close();
           providers.remove(key);
        }
  
        if (systemProviders.containsKey(key))
        {
           systemProviders.get(key).close();
           systemProviders.remove(key);
        }
     }
docs: /*
  (non-Javadoc)
  @see
  org.exoplatform.services.jcr.ext.app.SessionProviderService#removeSessionProvider(java.lang
  .Object)