docs: @Pure
  	public static String[] extensions(URL filename) {
  		if (filename == null) {
  			return new String[0];
  		}
  		final String largeBasename = largeBasename(filename);
  		final String[] parts = largeBasename.split(Pattern.quote(Character.toString(getFileExtensionCharacter())));
  		if (parts.length <= 1) {
  			return new String[0];
  		}
  		final String[] result = new String[parts.length - 1];
  		for (int i = 0; i < result.length; ++i) {
  			result[i] = decodeHTMLEntities(parts[i + 1]);
  		}
  		return result;
  	}