How can I initialise a static Map?

Question

How would you initialise a static Map in Java?

Method one: static initialiser
Method two: instance initialiser (anonymous subclass) or some other m

Answer 1

If you want unmodifiable map, finally java 9 added a cool factory method of to Map interface. Similar method is added to Set, List as well.

Map unmodifiableMap = Map.of("key1", "value1", "key2", "value2");