code: @SuppressWarnings("unchecked")
      @Override
      public <T extends OverlayContainer> T createOverlay(Class<T> overlayType, ArtifactContainer b) {
  
          //We don't use osgi to find overlay impls, as that's not required for now.
          //Instead we use a quick if/else block to handle the request.
          if (overlayType.equals(OverlayContainer.class)) {
              //we now only support the DirBasedOverlay, the in-memory one has been retired.
              //the naming and interfaces have been fixed up so that OverlayContainer now offers
              //the ability of the DirectoryBased one.
              return (T) new DirectoryBasedOverlayContainerImpl(b, this);
          }
  
          return null;
      }
docs: {@inheritDoc}