How to Initialize ArrayList Java with Values

There are multiple ways in which one can initialize an ArrayList in Java with values, just like Arrays, let us take a look at a few of them.

Using an Arrays.asList()

If you already have an array that is declared and initialized, you can create Initialize an ArrayList using it.

String[] countriesArray = {"USA","China","Canada","Japan","Australia"};
List<String> arrayList = new ArrayList<>(Arrays.asList(countriesArray));

You can do this in one step as well,

List<String> arrayList = new ArrayList&ly;>(Arrays.asList("USA","China","Canada","Japan","Australia"));

Java 8: Using the Stream.of(T values) method:

ArrayList<String> arrayList = new ArrayList<>(
      Stream.of("Australia", "India", "Sweden").collect(Collectors.toList())
  );

Java 9: Using the List.of(Element elements) method.

ArrayList<String> arrayList = new ArrayList<>(List.of("Apple", "Banana", "Orange"));

Java 10: Using the List.copyOf() method.

ArrayList countriesList = new ArrayList<>(Arrays.asList("Canada", "UK", "France"));
ArrayList newList = new ArrayList<>(List.copyOf(countriesList));

Using Java clone() method

ArrayList<String> cityList = new ArrayList<>(Arrays.asList("NYC", "Austin", "Chicago"));
ArrayList<String> cityListClone = (ArrayList<String>) cityList.clone();