code: @Override
      public synchronized void onFileDelete(File file) {
          // The file is already deleted, so we can't open it.
          // So we use the source.
          Set<FileWebJarLib> copy = new LinkedHashSet<>(libs);
          List<FileWebJarLib> toRemove = new ArrayList<>();
          for (FileWebJarLib lib : copy) {
              if (lib.source != null && lib.source.equals(file.getName())) {
                  // Found, remove it.
                  libs.remove(lib);
                  toRemove.add(lib);
                  // Delete the directory
                  FileUtils.deleteQuietly(lib.root);
              }
          }
  
          controller.removeWebJarLibs(toRemove);
      }
docs: An accepted file was deleted. We remove the contained libraries from the list and delete the directory in
  which the library was contained.
  <p>
  We can't open it to find the contained web jars,
  to we need to use the 'source' we set when the {@link org.wisdom.resources.FileWebJarLib} instances were created.
  
  @param file the file