Sorting ArrayList of Arraylist in java

Question

I have an ArrayList of ArrayList of String.

In Outer ArrayList on each index each Inner ArrayList has four items have four parameters.

1. Contacts Id

Answer 1

Assuming your Lists in your List has Strings in the order id, name, address and number (i.e. name is at index 1), you can use a Comparator, as follows:

List> list;
Collections.sort(list, new Comparator> () {
    @Override
    public int compare(List a, List b) {
        return a.get(1).compareTo(b.get(1));
    }
});

Incidentally, it matters not that you are using ArrayList: It is good programming practice to declare variables using the abstract type, i.e. List (as I have in this code).