A string array is serializable. So you can serialize it on a file
FileOutputStream fout = openFileOutput(FILENAME, Context.MODE_APPEND);
ObjectOutputStream oos = new ObjectOutputStream(fout);
oos.writeObject(pup);
oos.close();
and read back this way:
FileInputStream fin = openFileInput(FILENAME, Context.MODE_APPEND);
ObjectInputStream ois = new ObjectInputStream(fin);
String[] pup = (String[]) ois.readObject();
ois.close()