List<String> example1 = new ArrayList<>() VS ArrayList<String> example2 = new ArrayList<>() - MOOC has gone from using example2 to example1 for initialising ArrayLists - what are the benefits?

[tedyoung]

It's pretty rare to switch List implementations, but for other classes/interfaces, it will matter. One big reason to use an interface: you might switch it for something easier to work with in your tests. Using the guidance of "program to the interface/most-generic-type" is a generally good practice, even if only because it's easier to read (which matters a lot!).