code: public Collection<URI> loadFolder(final URI folderUri, final String pattern)
      {
          try {
              for (final MigrationLoader loader : loaders) {
                  if (loader.accept(folderUri)) {
                      return loader.loadFolder(folderUri, pattern);
                  }
              }
              return null;
          }
          catch (IOException ioe) {
              throw new MigratoryException(Reason.INTERNAL, ioe);
          }
      }
docs: Loads a collection of URIs from a given location. The resulting
  URIs may or may not loadable using this loader (e.g. a classpath folder
  can contain File or Jar URIs.