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

Java 9 has the following method to create an immutable list:

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

which is easily adapted to create a mutable list, if required:

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

Similar methods are available for Set and Map.