如何在 Java 中初始化二维字符串 ArrayList

Question

How to create a 2D ArrayList<ArrayList<String>> like

competition = [["A", "B"], 
["B", "C"],
["C", "A"]]

how can I declare it initialized during declaration? or the only way to do it as following

 ArrayList<ArrayList<String>> competitions = new ArrayList<>();

        ArrayList<String> x = new ArrayList<>();
        x.add("A");
        x.add("B");

        ArrayList<String> y = new ArrayList<>();
        y.add("B");
        y.add("C");

        ArrayList<String> z = new ArrayList<>();
        z.add("C");
        z.add("A");

competitions.add(x);
competitions.add(y);
competitions.add(z);

Answer 1

If I understand well you are trying to create an arrayList from an Array ou can do it with

new ArrayList<>(Arrays.asList(array));

Answer 2

You can use something like that if I understand your need:

List<List<String>> list = Arrays.asList(
           Arrays.asList("A", "B"),
           Arrays.asList("B", "C"),
           Arrays.asList("C", "A")
);

EDIT:

List<List<String>> list = new ArrayList<>(Arrays.asList(
            new ArrayList<>(Arrays.asList("A", "B")),
            new ArrayList<>(Arrays.asList("B", "C")),
            new ArrayList<>(Arrays.asList("C", "A"))
));