Initialization of an ArrayList in one line

Question

I wanted to create a list of options for testing purposes. At first, I did this:

ArrayList places = new ArrayList();
places.add(\         


        

Answer 1

It would be simpler if you were to just declare it as a List - does it have to be an ArrayList?

List places = Arrays.asList("Buenos Aires", "Córdoba", "La Plata");

Or if you have only one element:

List places = Collections.singletonList("Buenos Aires");

This would mean that places is immutable (trying to change it will cause an UnsupportedOperationException exception to be thrown).

To make a mutable list that is a concrete ArrayList you can create an ArrayList from the immutable list:

ArrayList places = new ArrayList<>(Arrays.asList("Buenos Aires", "Córdoba", "La Plata"));