code: @SuppressWarnings("resource")
  	public static AsyncWork<Properties, Exception> loadPropertiesFile(
  		File file, Charset charset, byte priority, boolean closeSynchronous, Listener<Properties> onDone
  	) {
  		FileIO.ReadOnly input = new FileIO.ReadOnly(file, priority);
  		return loadPropertiesFile(
  			input, charset, priority,
  			closeSynchronous ? IO.OperationType.SYNCHRONOUS : IO.OperationType.ASYNCHRONOUS,
  			onDone);
  	}
docs: Load properties from a file.