code: private static LogAdapterFactory getAdapterFactory()
     {
        // double-checked locking
        if (_adapterFactory == null)
        {
           synchronized (Logger.class)
           {
              if (_adapterFactory == null)
              {
                 _adapterFactory = createAdapterFactory();
              }
           }
        }
        return _adapterFactory;
     }
docs: This method provides access to the {@link LogAdapterFactory}. It will obtain the {@link LogAdapterFactory} lazily
  using {@link #createAdapterFactory()}.