Sorting ArrayList of Arraylist<String> 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
2. Contacts Name
3. Contacts Adress
4. Contacts Number

Now I want to sort the complete ArrayList of the on the basis of Contact Name Parameter.

Means I want to access the outer Arraylist and the inner ArrayList present on each index of outer Arraylist should be sorted according to contact Name.

Comparator / Comparable Interfaces not likely to help me.

Collection.sort can't help me

Sorting Arraylist of Arraylist of Bean. I have read this post but it is for ArrayList of ArrayList<Object>. How to figure out this problem?

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<String>> list;
Collections.sort(list, new Comparator<List<String>> () {
    @Override
    public int compare(List<String> a, List<String> 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).