docs: @Pure
  	public static String basename(File filename) {
  		if (filename == null) {
  			return null;
  		}
  		final String largeBasename = filename.getName();
  		final int idx = largeBasename.lastIndexOf(getFileExtensionCharacter());
  		if (idx <= 0) {
  			return largeBasename;
  		}
  		return largeBasename.substring(0, idx);
  	}