I have created a two dimensional ArrayList by inserting one row at a time.

No - you haven't - that is NOT possible.

An ArrayList is a list of single instances.

Those instances can be another object class. And if that other class implements the Comparable interface then you can use Collections.sort for the list.

The Java Tutorials has trails that show how to use ALL of the basic Java functionality

https://docs.oracle.com/javase/tutorial/collections/interfaces/order.html

Object Ordering

A List l may be sorted as follows.Collections.sort(l); 

If the List consists of String elements, it will be sorted into alphabetical order. If it consists of Date elements, it will be sorted into chronological order. How does this happen? String and Date both implement the <a class="APILink" href="https://docs.oracle.com/javase/8/docs/api/java/lang/Comparable.html" target="_blank">Comparable</a> interface. Comparable implementations provide a natural ordering for a class, which allows objects of that class to be sorted automatically. The following table summarizes some of the more important Java platform classes that implement Comparable.

Implement the Comparable interface in the class that implements those 'rows'

If you try to sort a list, the elements of which do not implement Comparable, Collections.sort(list) will throw a ClassCastException. Similarly, Collections.sort(list, comparator) will throw a ClassCastException if you try to sort a list whose elements cannot be compared to one another using the comparator.