Read and write arrayList of Objects by using HashMap

I want to write and read 'HashMap' to file.

My 'HashMap' is:

Map<String, ArrayList<Descipline>> mapDis = new HashMap<String, ArrayList<Descipline>>();

and I write to file like this:

String root = Environment.getExternalStorageDirectory().toString();

        Properties properties = new Properties();

        for (Map.Entry<String, ArrayList<Descipline>> entry : mapDis.entrySet()){
            properties.put(entry.getKey(), entry.getValue());
        }

        properties.store(new FileOutputStream(root + "/myMap.txt"), null);

But I don't know how to read it.

 Map<String, ArrayList<Descipline>> load = new HashMap<String, ArrayList<Descipline>>();

        Properties properties1 = new Properties();

        properties1.load(new FileInputStream(root + "/myMap.txt"));

        for (String key : properties1.stringPropertyNames()){
            //something will be here to read file
        }