Create Map in Java

Question

I\'d like to create a map that contains entries consisting of (int, Point2D)

How can I do this in Java?

I tried the following unsuc

Answer 1

Java 9

public static void main(String[] args) {
    Map<Integer,String> map = Map.ofEntries(entry(1,"A"), entry(2,"B"), entry(3,"C"));
}

Answer 2

Map<Integer, Point2D> hm = new HashMap<Integer, Point2D>();

Answer 3

There is even a better way to create a Map along with initialization:

Map<String, String> rightHereMap = new HashMap<String, String>()
{
    {
        put("key1", "value1");
        put("key2", "value2");
    }
};

For more options take a look here How can I initialise a static Map?

Answer 4

I use such kind of a Map population thanks to Java 9. In my honest opinion, this approach provides more readability to the code.

  public static void main(String[] args) {
    Map<Integer, Point2D.Double> map = Map.of(
        1, new Point2D.Double(1, 1),
        2, new Point2D.Double(2, 2),
        3, new Point2D.Double(3, 3),
        4, new Point2D.Double(4, 4));
    map.entrySet().forEach(System.out::println);
  }

Answer 5

Map <Integer, Point2D.Double> hm = new HashMap<Integer, Point2D>();
hm.put(1, new Point2D.Double(50, 50));